All practice questions

Question 12981Question →

Match each sodium compound listed on the left with its corresponding characteristic property, industrial preparation process, or commercial application on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Sodium peroxide matches with acting as an oxygen generator in breathing apparatus; Sodium hydroxide matches with industrial manufacture via brine electrolysis in a mercury cathode cell; Sodium hydrogentrioxocarbonate(IV) matches with thermal decomposition releasing carbon dioxide gas; Sodium trioxocarbonate(IV) decahydrate matches with efflorescence in dry atmosphere to form a monohydrate powder.

Each sodium compound is paired correctly according to its fundamental chemical behavior or industrial utility: Sodium peroxide reacts with carbon dioxide to regenerate oxygen; Sodium hydroxide is manufactured via the chlor-alkali process in Castner-Kellner mercury cells; Sodium hydrogentrioxocarbonate(IV) undergoes thermal decomposition to release carbon dioxide; and Sodium trioxocarbonate(IV) decahydrate loses hydration water through efflorescence.

Step-by-Step Solution

1

Analyze the chemical property and application of sodium peroxide (

\text{Na}_2\text{O}_2

).

Sodium peroxide reacts with carbon dioxide according to the equation

2\text{Na}_2\text{O}_2 + 2\text{CO}_2 \rightarrow 2\text{Na}_2\text{CO}_3 + \text{O}_2

, releasing oxygen gas.

This property makes it effective as an oxygen rebreather component.

2

Identify the industrial preparation method for sodium hydroxide (

\text{NaOH}

).

Sodium hydroxide is produced by electrolyzing concentrated brine (

\text{NaCl}_{(aq)}

) in a Castner-Kellner cell containing a mercury cathode.

Sodium ions discharge at the mercury cathode forming an amalgam, which reacts with water to yield pure

\text{NaOH}

.

3

Examine the thermal stability of sodium hydrogentrioxocarbonate(IV) (

\text{NaHCO}_3

).

Heating

\text{NaHCO}_3

causes decomposition:

2\text{NaHCO}_3 \xrightarrow{\Delta} \text{Na}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2

.

Alkali metal hydrogentrioxocarbonates decompose upon gentle heating to liberate carbon dioxide gas.

4

Determine the effect of air exposure on hydrated sodium trioxocarbonate(IV) (

\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O}

).

Exposure to dry air leads to the loss of nine water molecules:

\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O} \rightarrow \text{Na}_2\text{CO}_3\cdot \text{H}_2\text{O} + 9\text{H}_2\text{O}

.

This spontaneous loss of water of crystallization to the atmosphere is termed efflorescence.

Key Concept

Properties, Preparation, and Uses of Major Sodium Compounds

Question 12982Question →

A state government with a fixed capital expenditure allocation of $\text{N}800\text{ million}$ must choose between two mutually exclusive development projects: constructing a regional specialist hospital costing $\text{N}800\text{ million}$ or building an agricultural processing export terminal costing $\text{N}750\text{ million}$ that is projected to generate substantial trade revenues. If the government selects and constructs the regional specialist hospital, what is the real cost (opportunity cost) of this decision?

The foregone agricultural processing export terminal and the trade benefits it would have yielded.

The total monetary expenditure of

\text{N}800\text{ million}

incurred to build the specialist hospital.

The

\text{N}50\text{ million}

unspent balance remaining from the allocated capital budget.

An inward contraction of the state's Production Possibility Curve caused by capital expenditure.

Show answer & explanation

Answer: The foregone agricultural processing export terminal and the trade benefits it would have yielded.

Answer

The foregone agricultural processing export terminal and the trade benefits it would have yielded.

In economics, scarcity forces decision-makers to choose among competing alternatives. The real cost (opportunity cost) of choosing one option is the satisfied need or benefit of the next best alternative that is sacrificed. By choosing to build the hospital, the government gives up the opportunity to build the agricultural processing export terminal and capture its trade benefits.

Step-by-Step Solution

1

Identify the fundamental economic problem presented in the scenario.

The state government faces scarcity of capital resources (

\text{N}800\text{ million}

available) and must make a choice between competing projects.

Scarcity necessitates choice, which gives rise to opportunity cost.

2

Distinguish between money cost and real (opportunity) cost.

The money cost is the financial outlay of

\text{N}800\text{ million}

. The real cost is the alternative project sacrificed.

Economic analysis defines real cost as the benefit of the next best alternative sacrificed when a choice is made.

3

Determine the specific opportunity cost of selecting the hospital project.

Selecting the hospital means completely forfeiting the construction and economic revenues of the agricultural processing export terminal.

The export terminal represents the next best alternative option sacrificed due to limited financial capital.

Key Concept

Difference between Money Cost and Opportunity Cost in Resource Allocation

Question 12983Question →

Two long, parallel straight wires separated by a distance of $0.10\text{ m}$ carry currents of $5.0\text{ A}$ and $8.0\text{ A}$ in opposite directions. What is the magnitude and nature of the magnetic force per unit length exerted between the two wires? (Take $\mu_0 = 4\pi \times 10^{-7}\text{ T m A}^{-1}$ )

8.0 \times 10^{-5}\text{ N m}^{-1}

, repulsive

8.0 \times 10^{-5}\text{ N m}^{-1}

, attractive

4.0 \times 10^{-5}\text{ N m}^{-1}

, repulsive

4.0 \times 10^{-5}\text{ N m}^{-1}

, attractive

Show answer & explanation

Answer: $8.0 \times 10^{-5}\text{ N m}^{-1}$ , repulsive

Answer

The magnetic force per unit length is

8.0 \times 10^{-5}\text{ N m}^{-1}

and the nature of the force is repulsive.

The magnetic force per unit length between two parallel conductors carrying currents

I_1

and

I_2

separated by distance

d

is given by

\frac{F}{L} = \frac{\mu_0 I_1 I_2}{2\pi d}

. Substituting

I_1 = 5.0\text{ A}

,

I_2 = 8.0\text{ A}

,

d = 0.10\text{ m}

, and

\mu_0 = 4\pi \times 10^{-7}\text{ T m A}^{-1}

yields

\frac{F}{L} = 8.0 \times 10^{-5}\text{ N m}^{-1}

. Furthermore, conductors carrying currents in opposite directions exert a repulsive force on each other.

Step-by-Step Solution

1

Identify the given parameters and formula for force per unit length between two parallel conductors.

Given

I_1 = 5.0\text{ A}

,

I_2 = 8.0\text{ A}

,

d = 0.10\text{ m}

, and

\mu_0 = 4\pi \times 10^{-7}\text{ T m A}^{-1}

. Formula:

\frac{F}{L} = \frac{\mu_0 I_1 I_2}{2\pi d}

.

The magnetic field produced by one current-carrying conductor exerts a force on the second parallel conductor.

2

Substitute the values into the formula and evaluate the magnitude of the force per unit length.

$\frac{F}{L} = \frac{(4\pi \times 10^{-7}) \times 5.0 \times 8.0}{2\pi \times 0.10} = \frac{2 \times 10^{-7} \times 40.0}{0.10} = 8.0 \times 10^{-5}\text{ N m}^{-1}$.

Simplifying

\frac{4\pi}{2\pi} = 2

allows direct scalar computation.

3

Determine the direction/nature of the magnetic force based on current direction.

Since the currents flow in opposite directions, the magnetic forces between the conductors are repulsive.

By the right-hand grip rule and magnetic force laws, parallel currents in opposite directions experience mutual repulsion.

Key Concept

Magnetic force per unit length between parallel current-carrying conductors

Question 12984Question →

A deuteron of mass $2m_p$ and charge $e$ , and an $\alpha$ -particle of mass $4m_p$ and charge $2e$ , are accelerated from rest through potential differences of $V_d$ and $V_\alpha$ respectively. If both particles acquire equal de Broglie wavelengths, what is the ratio of their accelerating potential differences, $\frac{V_d}{V_\alpha}$ ?

4 : 1

1 : 4

2 : 1

16 : 1

Show answer & explanation

Answer: $4 : 1$

Answer

The ratio of the accelerating potential differences

\frac{V_d}{V_\alpha}

is

4 : 1

.

Using the de Broglie wavelength equation

\lambda = \frac{h}{\sqrt{2mqV}}

, setting

\lambda_d = \lambda_\alpha

gives

m_d q_d V_d = m_\alpha q_\alpha V_\alpha

. Substituting

m_d = 2m_p

,

q_d = e

,

m_\alpha = 4m_p

, and

q_a = 2e

yields

2 V_d = 8 V_\alpha

, which simplifies directly to

\frac{V_d}{V_\alpha} = 4 : 1

.

Step-by-Step Solution

1

Express the de Broglie wavelength in terms of particle mass, charge, and accelerating potential difference.

\lambda = \frac{h}{p} = \frac{h}{\sqrt{2mqV}}

Kinetic energy gained by a charged particle in an electric field is

E_k = qV

, and momentum is

p = \sqrt{2mE_k} = \sqrt{2mqV}

.

2

Set the de Broglie wavelengths of the deuteron and

\alpha

-particle equal to each other.

\frac{h}{\sqrt{2 m_d q_d V_d}} = \frac{h}{\sqrt{2 m_\alpha q_\alpha V_\alpha}} \implies m_d q_d V_d = m_\alpha q_\alpha V_\alpha

Equal wavelengths mean their denominators in the de Broglie expression must be equal.

3

Substitute the given values for mass and charge into the equality.

(2m_p)(e) V_d = (4m_p)(2e) V_\alpha \implies 2 m_p e V_d = 8 m_p e V_\alpha

Deuteron has mass

2m_p

and charge

e

;

\alpha

-particle has mass

4m_p

and charge

2e

.

4

Solve for the ratio

\frac{V_d}{V_\alpha}

.

\frac{V_d}{V_\alpha} = \frac{8}{2} = 4

Simplifying the algebraic equation by cancelling common terms

m_p

and

e

.

Key Concept

De Broglie Wavelength of Accelerated Charged Particles

Question 12985Question →

In angiosperms, the mature female gametophyte (embryo sac) completely lacks archegonia, whereas gymnosperms typically develop distinct multicellular archegonia within their female gametophytes.

True

False

Show answer & explanation

Answer: True

Answer

True. Gymnosperms form multicellular archegonia inside the female gametophyte to produce egg cells, whereas angiosperms possess a reduced female gametophyte (embryo sac) that completely lacks archegonia.

The statement accurately reflects an essential evolutionary distinction between seed plant divisions: gymnosperm ovules house female gametophytes with defined archegonia, whereas angiosperm embryo sacs have lost archegonial structures altogether.

Step-by-Step Solution

1

Examine the female reproductive structures in gymnosperms.

Gymnosperm female gametophytes differentiate into multicellular archegonia, each containing an egg cell.

Archegonia are ancestral gametangia retained in lower vascular plants and most gymnosperm lineages.

2

Examine the female gametophyte structure in angiosperms.

Angiosperms develop a highly reduced 8-nucleate, 7-celled embryo sac containing an egg apparatus (egg cell and synergids) without any archegonial structure.

Evolutionary trends in spermatophytes involve progressive reduction of the gametophyte phase, culminating in the total absence of archegonia in angiosperms.

Key Concept

Structural differences in female gametophytes and presence of archegonia between Gymnosperms and Angiosperms

Estimated Time:1m 0s

Question 12986Question →

Complete the statement below regarding the scope of economic analysis.

Fill in the blanks below

The branch of economics that examines the decision-making of individual units such as consumers and firms is known as economics, whereas the branch that deals with aggregate economic performance such as general price levels and total national output is called economics.

Show answer & explanation

Answer

The statement is completed using 'micro' (or 'microeconomics') for blank 1, and 'macro' (or 'macroeconomics') for blank 2.

Microeconomics focuses on individual decision-makers (such as individual consumers, workers, households, and single firms) and specific market price determination. In contrast, macroeconomics looks at aggregate economic variables including national income, aggregate demand, total employment, and inflation across the broader economy.

Step-by-Step Solution

1

Analyze the first part of the statement focusing on individual economic decision-making units.

Individual units like households, buyers, and firms fall under microeconomics.

Microeconomics studies small-scale economic behavior and individual market interactions.

2

Analyze the second part of the statement focusing on economy-wide aggregates.

Aggregates such as national output, gross domestic product, and general price level fall under macroeconomics.

Macroeconomics studies the structure, performance, and decision-making of an entire economy.

Key Concept

Branches of Economic Analysis (Microeconomics vs. Macroeconomics)

Estimated Time:1m 0s

Question 12987Question →

In a physics experiment to determine the acceleration due to gravity $g$ using a free-fall apparatus, the distance of fall is measured as $h = (2.00 \pm 0.04)\text{ m}$ and the duration of fall is measured as $t = (0.50 \pm 0.01)\text{ s}$ . Given that $g = \frac{2h}{t^2}$ , what is the percentage error in the calculated value of $g$ ?

Show answer & explanation

Answer: 6

Answer

The percentage error in the calculated value of

g

is 6%.

For a physical quantity defined by

g = \frac{2h}{t^2}

, the maximum percentage error is determined by adding the percentage error in

h

to twice the percentage error in

t

. The percentage error in

h

is

\frac{0.04}{2.00} \times 100\% = 2\%

and in

t

is

\frac{0.01}{0.50} \times 100\% = 2\%

. Therefore, the total percentage error in

g

is

2\% + 2(2\%) = 6\%

.

Step-by-Step Solution

1

Calculate the percentage error in the distance measurement

h

2%

The fractional error in height is

\frac{\Delta h}{h} = \frac{0.04}{2.00} = 0.02

, which corresponds to

2\%

.

2

Calculate the percentage error in the time measurement

t

2%

The fractional error in time is

\frac{\Delta t}{t} = \frac{0.01}{0.50} = 0.02

, which corresponds to

2\%

.

3

Apply the power-law error propagation rule to find the maximum percentage error in

g

6%

For

g = \frac{2h}{t^2}

, the total relative error is

\frac{\Delta g}{g} = \frac{\Delta h}{h} + 2\frac{\Delta t}{t} = 2\% + 2(2\%) = 6\%

, since the exponent of

t

is 2.

Key Concept

Error propagation in physical formulas involving powers and quotients

Estimated Time:2m 0s

Question 12988Question →

A furniture manufacturer expands its output of wooden tables, resulting in an increased requirement for skilled carpenters. What type of demand is demonstrated by the demand for carpenters?

Derived demand

Joint demand

Competitive demand

Composite demand

Show answer & explanation

Answer: Derived demand

Answer

Derived demand

Derived demand arises when the demand for a good or service (such as skilled labour) is determined by the demand for the final commodity it produces. In this scenario, carpenters are hired because there is demand for wooden tables.

Step-by-Step Solution

1

Analyze the economic relationship between wooden tables and carpenters.

Carpenters provide factor labour required for manufacturing wooden tables.

Classifying the demand type requires establishing whether demand for the input is dependent on demand for the final output.

2

Apply the definition of derived demand.

Demand for carpenters increases as a direct consequence of the rise in production of wooden tables.

Derived demand occurs when a resource or factor of production is wanted solely because it helps produce another commodity.

Key Concept

Derived Demand

Estimated Time:1m 0s

Question 12989Question →

A simple pendulum has a period of oscillation of $1.6\text{ s}$ on the surface of the Earth, where the acceleration due to gravity is $10.0\text{ m/s}^2$ . What is the period of oscillation of this pendulum when placed on a moon where the acceleration due to gravity is $2.5\text{ m/s}^2$ ?

Show answer & explanation

Answer: 3.2

Answer

The period of oscillation of the pendulum on the moon is

3.2\text{ s}

.

The period of a simple pendulum is given by

T = 2\pi \sqrt{\frac{l}{g}}

. Because the length

l

is constant, period is inversely proportional to the square root of acceleration due to gravity (

T \propto \frac{1}{\sqrt{g}}

). Reducing the local gravity from

10.0\text{ m/s}^2

to

2.5\text{ m/s}^2

decreases gravity by a factor of 4, which increases the period by a factor of

\sqrt{4} = 2

. Multiplying the initial period of

1.6\text{ s}

by 2 yields

3.2\text{ s}

.

Step-by-Step Solution

1

Relate the period of oscillation of a simple pendulum to gravitational acceleration.

The period formula is

T = 2\pi \sqrt{\frac{l}{g}}

, showing that

T

is inversely proportional to

\sqrt{g}

.

The length of the pendulum

l

remains unchanged.

2

Formulate a ratio comparing the pendulum's period on the moon to its period on Earth.

\frac{T_{moon}}{T_{earth}} = \sqrt{\frac{g_{earth}}{g_{moon}}}

Dividing the two equations cancels the constant terms

2\pi

and

\sqrt{l}

.

3

Substitute the known numerical values and solve for

T_{moon}

.

T_{moon} = 1.6 \times \sqrt{\frac{10.0}{2.5}} = 1.6 \times 2.0 = 3.2\text{ s}

The ratio of gravities is 4, whose square root is 2, doubling the initial period.

Key Concept

Dependence of Simple Pendulum Period on Gravitational Acceleration

Estimated Time:1m 30s

Question 12990Question →

Match each classical trade theory or economic principle on the left with its corresponding foundational premise or proponent on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Absolute Advantage Theory matches Adam Smith's absolute labor cost approach; Comparative Advantage Theory matches David Ricardo's relative opportunity cost model; Opportunity Cost Theory of Trade matches Gottfried Haberler's production possibility curve framework; Limits to Terms of Trade matches the domestic cost ratios boundary.

Each theory is paired correctly with its originator or core economic premise: Adam Smith established absolute advantage based on absolute cost efficiency; David Ricardo formulated comparative advantage based on relative cost ratios; Gottfried Haberler introduced the opportunity cost curve model; and the limits to the terms of trade are set by internal opportunity cost ratios.

Step-by-Step Solution

1

Identify the proponent and core assumption of Absolute Advantage.

Adam Smith proposed that countries should specialize in goods where they possess absolute labor cost advantages.

This establishes the historical origin of free trade theory.

2

Identify the proponent and core assumption of Comparative Advantage.

David Ricardo showed that mutual gains from trade occur whenever relative opportunity costs differ between nations.

This extends Smith's model to cases where one country is more efficient in all lines of production.

3

Identify Haberler's contribution to trade theory.

Gottfried Haberler reformulated comparative advantage using the opportunity cost concept derived from production possibility frontiers.

This removed the restrictive assumption of the labor theory of value.

4

Determine the condition for mutually beneficial terms of trade.

The terms of trade must fall between the domestic opportunity cost ratios of both trading countries.

If the exchange rate falls outside these bounds, at least one nation would experience a net loss from trade.

Key Concept

Foundational Theories of International Trade and Terms of Trade Limits

Question 12991Question →

Biological variations in living organisms manifest through distinct phenotypic patterns and underlying genetic mechanisms. Pair each genetic scenario or population trait feature on the left with its correct classification or descriptive feature on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Human body mass and adult height pairs with continuous variation controlled by polygenes and modified by environmental factors; Human Rhesus factor status and ABO blood group pairs with discontinuous variation controlled by monogenic inheritance independent of environmental influence; Frequency curve displaying a smooth, continuous spectrum pairs with graphical profile typical of quantitative inheritance within a population; Histogram featuring separate, distinct bars pairs with graphical profile typical of qualitative inheritance within a population.

Continuous variation involves quantitative traits such as height and body mass, governed by multiple genes (polygenes) and environmental conditions, producing a smooth distribution curve. Discontinuous variation involves qualitative traits such as blood groups, controlled by major single genes (monogenes), producing discrete, non-overlapping categories represented by separate bars on a histogram.

Step-by-Step Solution

1

Analyze polygenic traits and environmental influence.

Human body mass and height vary continuously across a spectrum and respond to environmental factors like diet.

Multiple additive genes working together with environmental conditions produce a continuous range of phenotypes.

2

Identify traits governed by single genes producing distinct categories.

Blood groups (ABO and Rhesus factor) are strictly categorical without intermediate types.

Monogenic inheritance causes discontinuous phenotypic classes that are immune to environmental modifications.

3

Correlate graph types with quantitative and qualitative variation.

A smooth curve depicts quantitative variation, while isolated bars depict qualitative variation.

Quantitative traits span a continuous spectrum forming a bell curve, whereas qualitative traits yield clear-cut distinct categories.

Key Concept

Distinction between continuous (polygenic, quantitative) and discontinuous (monogenic, qualitative) variation

Estimated Time:1m 30s

Question 12992Question →

Which of the following diagnostic anatomical features distinguishes members of the phylum Coelenterata (Cnidaria) from other lower invertebrate phyla such as Porifera, Platyhelminthes, and Nematoda?

Possession of specialized stinging cells called cnidocytes (nematocysts) embedded in a diploblastic body wall

Possession of flame cells (protonephridia) dedicated to osmoregulation and nitrogenous waste removal

Possession of flagellated collar cells (choanocytes) that line an internal water canal system

Possession of a fluid-filled pseudocoelom that acts as a hydrostatic skeleton

Show answer & explanation

Answer: Possession of specialized stinging cells called cnidocytes (nematocysts) embedded in a diploblastic body wall

Answer

The possession of specialized stinging cells called cnidocytes (nematocysts) embedded in a diploblastic body wall is unique to members of the phylum Coelenterata.

Coelenterates (such as Hydra, Obelia, and jellyfish) are characterized by a diploblastic body wall containing specialized stinging cells called cnidocytes (or nematocysts). These cells function in paralyzing prey and providing defensive mechanisms, a feature absent in Porifera, Platyhelminthes, and Nematoda.

Step-by-Step Solution

1

Analyze the structural organization of Coelenterata (Cnidaria)

Coelenterates are tissue-grade, diploblastic organisms (outer ectoderm and inner endoderm) exhibiting radial symmetry.

Identifying the level of cellular and tissue organization narrows down characteristic features.

2

Identify specialized cell types specific to Coelenterata

Cnidocytes (containing stinging capsules called nematocysts) are present on tentacles and body epidermis for prey capture and defense.

Cnidocytes are unique diagnostic cells found exclusively in Coelenterata.

3

Compare with diagnostic structures of neighboring lower invertebrate phyla

Choanocytes belong to Porifera, flame cells belong to Platyhelminthes, and a pseudocoelom belongs to Nematoda.

Distinguishing distinct specialized structures eliminates wrong choices linked to other lower invertebrate phyla.

Key Concept

Diagnostic features of lower invertebrate phyla (Coelenterata vs. Porifera, Platyhelminthes, and Nematoda)

Estimated Time:1m 0s

Question 12993Question →

Ammonia ( $\text{NH}_3$ ) is manufactured in bulk for agricultural fertilizers, whereas phenolphthalein is synthesized in small quantities as a high-purity laboratory indicator. Which of the following correctly describes the industrial classification and manufacturing method for each chemical?

Ammonia is a heavy chemical produced by a continuous process, while phenolphthalein is a fine chemical produced by a batch process.

Ammonia is a fine chemical produced by a continuous process, while phenolphthalein is a heavy chemical produced by a batch process.

Ammonia is a heavy chemical produced by a batch process, while phenolphthalein is a fine chemical produced by a continuous process.

Both ammonia and phenolphthalein are heavy chemicals produced by continuous industrial processes.

Show answer & explanation

Answer: Ammonia is a heavy chemical produced by a continuous process, while phenolphthalein is a fine chemical produced by a batch process.

Answer

Ammonia is classified as a heavy chemical produced by a continuous process, while phenolphthalein is classified as a fine chemical produced by a batch process.

Heavy chemicals are inorganic or organic substances manufactured on a massive scale (high tonnage) using continuous processes because of their low unit cost and continuous industrial demand (e.g., ammonia, tetraoxosulfate(VI) acid, sodium hydroxide). Fine chemicals are specialized chemicals made in relatively small quantities with high purity levels using batch processes (e.g., pharmaceuticals, dyes, analytical indicators like phenolphthalein).

Step-by-Step Solution

1

Analyze the scale of production and usage for Ammonia (NH3)

Ammonia is produced in thousands of tonnes per day as a fundamental starting material for fertilizers and nitric acid.

Chemicals produced in high volume and low unit cost for broad industrial utility are classified as heavy chemicals, and high demand necessitates a continuous process.

2

Analyze the scale of production and usage for Phenolphthalein

Phenolphthalein is produced in small quantities to meet precise purity specifications for acid-base titrations.

Chemicals manufactured in low volume, high purity, and high unit price for specialized applications are classified as fine chemicals, which are typically made in batch processes.

3

Match both substances to the correct operational processes

Ammonia = Heavy chemical (Continuous process); Phenolphthalein = Fine chemical (Batch process).

This correctly pairs chemical category with the corresponding mode of plant operation.

Key Concept

Classification of Heavy and Fine Chemicals

Question 12994Question →

Match each physical characteristic of money on the left with its corresponding economic definition on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Portability matches with the ability to be carried conveniently from one location to another; Divisibility matches with the capability of being broken down into smaller denominations without loss of value; Homogeneity matches with uniformity in quality, appearance, and value across all units; Durability matches with resistance to physical wear and tear.

Portability ensures money can be easily carried for transactions; Divisibility ensures transactions of all sizes can be settled with exact change; Homogeneity guarantees equal purchasing power across identical notes; and Durability preserves physical usability over time.

Step-by-Step Solution

1

Identify the core definition of each money attribute

Portability relates to transportability, Divisibility relates to sub-units, Homogeneity relates to uniformity, and Durability relates to physical persistence.

Each characteristic addresses a specific limitation of commodity or barter currencies.

2

Pair each characteristic with its exact defining description

All 4 characteristics matched to their precise functional definitions.

Matching each term with its standard economic property ensures conceptual accuracy.

Key Concept

Essential Characteristics of Money

Question 12995Question →

Match each industrialization strategy or policy instrument with its corresponding economic feature or primary objective.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Import Substitution Strategy matches with replacing imported manufactured goods; Export Promotion Strategy matches with encouraging domestic manufacturing targeted at international markets; Protective Tariffs match with imposing duties to shield domestic infant industries; Export Subsidies match with providing financial assistance to lower export production costs.

Each industrial term accurately corresponds to its core definition: Import Substitution aims to replace foreign imports with local products; Export Promotion builds manufacturing capacity for international sales; Protective Tariffs shield infant industries by raising import costs; and Export Subsidies assist exporters in competing globally.

Step-by-Step Solution

1

Differentiate between inward-looking and outward-looking industrial development strategies.

Import substitution is an inward-looking strategy aimed at satisfying domestic demand locally, while export promotion is an outward-looking strategy focused on international sales.

This establishes the fundamental objective of each strategy.

2

Identify the trade policy tools associated with domestic protection versus export expansion.

Protective tariffs raise import costs to safeguard local producers, while export subsidies financially support producers aiming for overseas markets.

This links policy instruments directly to their intended operational mechanisms.

Key Concept

Industrial Sector: Manufacturing, Import Substitution, and Export Promotion

Question 12996Question →

An electric immersion heater rated at $500\text{ W}$ is used to heat a liquid of mass $0.40\text{ kg}$ from an initial temperature of $25^\circ\text{C}$ to its boiling point at $75^\circ\text{C}$ , and then vaporize half of the liquid at constant temperature. If the specific heat capacity of the liquid is $2500\text{ J kg}^{-1}\text{ K}^{-1}$ and its specific latent heat of vaporization is $5.0 \times 10^5\text{ J kg}^{-1}$ , what is the total time required for this process?

300\text{ s}

500\text{ s}

200\text{ s}

10,100\text{ s}

Show answer & explanation

Answer: $300\text{ s}$

Answer

The total time required for the process is

300\text{ s}

.

The correct response combines the energy needed for thermal elevation to the boiling point (

50,000\text{ J}

) with the energy required for vaporizing half the mass at constant temperature (

100,000\text{ J}

), yielding a total energy of

150,000\text{ J}

. Dividing this total energy by the

500\text{ W}

power rating yields exactly

300\text{ s}

.

Step-by-Step Solution

1

Calculate the sensible heat (

Q_1

) required to heat

0.40\text{ kg}

of liquid from

25^\circ\text{C}

to

75^\circ\text{C}

.

Q_1 = m c \Delta T = 0.40\text{ kg} \times 2500\text{ J kg}^{-1}\text{ K}^{-1} \times (75 - 25)\text{ K} = 50,000\text{ J}

.

Before phase change can occur, the liquid must first reach its boiling point.

2

Calculate the latent heat (

Q_2

) required to vaporize half of the liquid mass (

m_{\text{vap}} = 0.20\text{ kg}

).

Q_2 = m_{\text{vap}} L_v = 0.20\text{ kg} \times 5.0 \times 10^5\text{ J kg}^{-1} = 100,000\text{ J}

.

Phase change at the boiling point occurs at constant temperature and depends strictly on latent heat.

3

Sum the total heat energy (

Q_{\text{total}}

) and compute time (

t

) using heater power (

P = 500\text{ W}

).

Q_{\text{total}} = Q_1 + Q_2 = 150,000\text{ J}

, so

t = \frac{Q_{\text{total}}}{P} = \frac{150,000\text{ J}}{500\text{ W}} = 300\text{ s}

.

Thermal power is defined as energy supplied per unit time (

P = \frac{Q}{t}

).

Key Concept

Latent Heat and Energy Balance in Phase Transitions

Estimated Time:2m 30s

Question 12997Question →

In economic analysis, domestic trade differs significantly from international trade across several structural dimensions. Match each dimension of trade distinction on the left with its correct defining characteristic on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Currency and Payment Mechanism matches with 'Subject to exchange rate fluctuations and foreign currency regulation'; Mobility of Factors of Production matches with 'Restricted by international border controls, immigration laws, and cultural differences'; Trade Barriers and Commercial Policies matches with 'Involves tariffs, quotas, embargoes, and customs inspections imposed by sovereign states'; and Documentation and Transport Expenses matches with 'Requires bills of lading, consular invoices, marine insurance, and cross-border freight handling'.

Each feature correctly pairs a core economic distinction between domestic trade and international trade with its defining economic manifestation. Currency mechanisms involve foreign exchange, factor mobility faces international restrictions, commercial policies introduce tariffs and quotas across borders, and international transportation requires specialized legal shipping documents.

Step-by-Step Solution

1

Analyze the payment differences between internal and foreign trade.

Identify that currency differences and foreign exchange rates are specific to international trade.

Domestic trade uses a single domestic legal tender, while international trade involves multiple foreign currencies.

2

Examine how factors of production move between regions versus across sovereign nations.

Recognize that factor mobility (labor, capital) is high within domestic borders but restricted across international boundaries.

Immigration laws, passport controls, and sovereign regulations limit international factor movement.

3

Evaluate the regulatory and commercial policy tools applied to trade.

Connect commercial policies (tariffs, quotas, embargoes) specifically to sovereign cross-border trade.

Governments do not place tariffs on goods moving between domestic states or towns.

4

Compare transport costs and legal documentation requirements.

Associate complex paperwork like bills of lading and consular invoices with international shipping.

Long-distance ocean/air transport and foreign customs clearance demand specialized international documentation.

Key Concept

Distinction Between Domestic and International Trade

Estimated Time:1m 30s

Question 12998Question →

If two solid blocks are manufactured from the exact same uniform metal but one has twice the mass of the other, the block with the larger mass will have a higher heat capacity, even though both blocks have the same specific heat capacity.

True

False

Show answer & explanation

Answer: True

Answer

The statement is true because specific heat capacity is an intensive property depending solely on the material, while heat capacity is an extensive property proportional to mass.

Specific heat capacity (

c

) is a characteristic property of a substance (

\text{J kg}^{-1}\text{ K}^{-1}

) and is independent of sample size. Heat capacity (

C = mc

) measures total thermal energy required per unit temperature rise (

\text{J K}^{-1}

) and scales directly with mass. Therefore, a larger mass of the same metal has a higher heat capacity while maintaining an identical specific heat capacity.

Step-by-Step Solution

1

Define specific heat capacity and identify its nature.

Specific heat capacity (

c = \frac{Q}{m\Delta T}

) is an intensive property, meaning it remains constant for any sample of the same material regardless of mass.

Intensive properties do not depend on the quantity of matter present.

2

Define heat capacity and relate it to mass and specific heat capacity.

Heat capacity (

C = \frac{Q}{\Delta T} = mc

) is an extensive property and is directly proportional to mass (

m

).

Extensive properties scale with the size or mass of the system.

3

Compare the two blocks.

Since both blocks are made of the same metal,

c

is identical for both. However, because

C = mc

, the block with greater mass has a higher heat capacity.

Doubling mass doubles total heat capacity while leaving specific heat capacity unchanged.

Key Concept

Distinction between Intensive (Specific Heat Capacity) and Extensive (Heat Capacity) Thermal Properties

Question 12999Question →

On a warm day, the saturated vapour pressure of water at an ambient temperature of $25^\circ\text{C}$ is $24\text{ mmHg}$ . If the actual partial pressure of water vapour in the air at this temperature is $18\text{ mmHg}$ , what is the relative humidity of the atmosphere?

75\%

133\%

25\%

43\%

Show answer & explanation

Answer: $75\%$

Answer

The relative humidity of the atmosphere is

75\%

.

The relative humidity is defined as the ratio of the partial vapour pressure of water present in the air to the saturated vapour pressure at the ambient temperature, expressed as a percentage. Dividing

18\text{ mmHg}

by

24\text{ mmHg}

yields

0.75

, which equals

75\%

.

Step-by-Step Solution

1

Identify the formula for relative humidity.

\text{Relative Humidity} = \left(\frac{\text{Partial Vapour Pressure}}{\text{Saturated Vapour Pressure at same temp}}\right) \times 100\%

Relative humidity measures how close atmospheric air is to saturation at a given temperature.

2

Substitute the given values into the formula.

\text{Relative Humidity} = \left(\frac{18\text{ mmHg}}{24\text{ mmHg}}\right) \times 100\%

The partial pressure is

18\text{ mmHg}

and the saturated vapour pressure is

24\text{ mmHg}

.

3

Calculate the final percentage.

\text{Relative Humidity} = 0.75 \times 100\% = 75\%

Simplifying

\frac{18}{24}

gives

\frac{3}{4}

, which corresponds to

0.75

or

75\%

.

Key Concept

Relative humidity is the ratio of the actual mass (or partial pressure) of water vapour in a given volume of air to the maximum mass (or saturated vapour pressure) of water vapour that the same volume of air can hold at that same temperature, expressed as a percentage.

Question 13000Question →

In a free market economy, a permanent shift in consumer preference occurs from print newspapers to digital news platforms. Under the automatic operation of the price mechanism, how are productive resources reallocated between these two industries?

Declining prices and profits in print journalism signal capital and labor to migrate toward the more profitable digital news sector.

A central planning board issues directives instructing print publishing firms to transfer their equipment and workforce to digital media organizations.

The state provides production subsidies to print publishers to maintain employment equality across both sectors.

Resources remain permanently locked in print journalism because the high initial monetary cost of printing machinery cannot be recovered.

Show answer & explanation

Answer: Declining prices and profits in print journalism signal capital and labor to migrate toward the more profitable digital news sector.

Answer

Declining prices and profits in print journalism signal capital and labor to migrate toward the more profitable digital news sector.

In a pure free market economy (capitalism), resource allocation is directed by the price mechanism driven by consumer sovereignty and the profit motive. When consumer preferences shift from print to digital news, falling demand for print newspapers drives down prices and profitability in print publishing. Conversely, strong demand for digital news pushes up revenue potential in digital media. These relative price and profit changes act as signals to self-interested producers to cut back on print publishing and redirect capital, labor, and entrepreneurship toward the expanding digital news sector.

Step-by-Step Solution

1

Analyze the consumer demand shift

Demand for print newspapers falls while demand for digital news rises.

Consumer preference changes directly alter market demand curves in a capitalist economy.

2

Evaluate the price and profit signals

Prices and revenue in print media decline, resulting in lower profits or losses, whereas digital platforms experience rising prices and profit margins.

The price mechanism uses relative prices and profit motives as signals to producers.

3

Determine factor mobility and resource reallocation

Profit-seeking firms and resource owners shift productive factors away from print media into digital news platforms without central coordination.

In a free market system, resources naturally flow to sectors with higher relative profitability.

Key Concept

Price Mechanism and Resource Allocation in Free Market Capitalism

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Answer

Step-by-Step Solution

Key Concept