All practice questions

Question 6681Question →

An electric heating element made of a wire with resistivity $1.0 \times 10^{-6}\,\Omega\cdot\text{m}$ and a uniform cross-sectional area of $5.0 \times 10^{-7}\,\text{m}^2$ carries a steady current of $4.0\,\text{A}$ when connected to a $240\,\text{V}$ direct-current supply. What is the length of the wire?

15\,\text{m}

30\,\text{m}

60\,\text{m}

120\,\text{m}

Show answer & explanation

Answer: $30\,\text{m}$

Answer

30\,\text{m}

By applying Ohm's Law (

R = \frac{V}{I}

), the total resistance of the heating element is found to be

60\,\Omega

. Substituting this along with resistivity

\rho = 1.0 \times 10^{-6}\,\Omega\cdot\text{m}

and cross-sectional area

A = 5.0 \times 10^{-7}\,\text{m}^2

into the resistivity equation

R = \frac{\rho L}{A}

yields

L = \frac{R A}{\rho} = 30\,\text{m}

.

Step-by-Step Solution

1

Calculate the electrical resistance of the wire using Ohm's Law.

R = \frac{V}{I} = \frac{240\,\text{V}}{4.0\,\text{A}} = 60\,\Omega

The resistance must be determined from the operational potential difference and current before finding the geometric dimensions.

2

Relate resistance to length, cross-sectional area, and resistivity using

R = \frac{\rho L}{A}

.

60\,\Omega = \frac{(1.0 \times 10^{-6}\,\Omega\cdot\text{m}) \times L}{5.0 \times 10^{-7}\,\text{m}^2}

The resistance of a uniform conductor is directly proportional to its length and inversely proportional to its cross-sectional area.

3

Solve the equation for the wire length

L

.

L = \frac{60 \times 5.0 \times 10^{-7}}{1.0 \times 10^{-6}} = 30\,\text{m}

Rearranging the formula gives

L = \frac{R A}{\rho}

to isolate the required length.

Key Concept

Relationship between potential difference, current, resistance, and wire dimensions (

R = \frac{V}{I} = \frac{\rho L}{A}

)

Question 6682Question →

A $14.3\text{ g}$ sample of washing soda crystals, hydrated sodium trioxocarbonate(IV) ( $\text{Na}_2\text{CO}_3 \cdot 10\text{H}_2\text{O}$ ), is completely dissolved in water. Calculate the total number of moles of oxygen atoms present in this sample. [Relative atomic masses: $\text{Na} = 23$ , $\text{C} = 12$ , $\text{O} = 16$ , $\text{H} = 1$ ]

Show answer & explanation

Answer: 0.65

Answer

The total number of moles of oxygen atoms present in the sample is 0.65 mol.

The molar mass of

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

is

286\text{ g/mol}

. A mass of

14.3\text{ g}

corresponds to

\frac{14.3}{286} = 0.05\text{ mol}

of the compound. Since each formula unit contains 13 oxygen atoms (3 from the trioxocarbonate anion and 10 from the water of crystallization), the total moles of oxygen atoms present is

0.05 \times 13 = 0.65\text{ mol}

.

Step-by-Step Solution

1

Calculate the molar mass of

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

.

Molar mass =

286\text{ g/mol}

.

Summing the atomic masses of all constituent atoms, including the 10 water molecules of crystallization:

(2 \times 23) + 12 + (3 \times 16) + 10 \times (18) = 286\text{ g/mol}

.

2

Calculate the number of moles of

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

present in the sample.

Moles of compound =

0.05\text{ mol}

.

Dividing the given sample mass by its molar mass:

\frac{14.3\text{ g}}{286\text{ g/mol}} = 0.05\text{ mol}

.

3

Determine the stoichiometric ratio of oxygen atoms per mole of hydrated compound.

13 moles of O atoms per 1 mole of

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

.

Each formula unit contains 3 oxygen atoms from the trioxocarbonate group and 10 oxygen atoms from the ten water of crystallization molecules (

3 + 10 = 13

).

4

Multiply the moles of compound by the number of oxygen atoms per formula unit.

Total moles of O atoms =

0.65\text{ mol}

.

Calculating total oxygen moles:

0.05\text{ mol} \times 13 = 0.65\text{ mol}

.

Key Concept

The Mole Concept, Molar Mass, and Stoichiometric Ratios in Hydrated Salts

Question 6683Question →

The financial extract of Chief Adebayo's enterprise at the end of the trading year shows the following balances:

- Fixtures and Fittings: $\text{₦}650,000$
- Motor Vehicles: $\text{₦}1,200,000$
- Inventory: $\text{₦}350,000$
- Trade Debtors: $\text{₦}180,000$
- Cash at Bank: $\text{₦}120,000$
- Trade Creditors: $\text{₦}220,000$
- Accrued Expenses: $\text{₦}30,000$

What is the capital employed of the business?

₦2,100,000

₦2,250,000

₦2,500,000

₦2,750,000

Show answer & explanation

Answer: ₦2,250,000

Answer

₦2,250,000

Capital Employed is defined as Fixed Assets plus Working Capital (or Total Assets minus Current Liabilities). Fixed Assets equal

\text{₦}1,850,000

and Working Capital equals

\text{₦}400,000

(

\text{₦}650,000 - \text{₦}250,000

), yielding

\text{₦}2,250,000

.

Step-by-Step Solution

1

Calculate Total Fixed Assets

Fixtures and Fittings (₦650,000) + Motor Vehicles (₦1,200,000) = ₦1,850,000

Identify long-term assets used in generating revenue.

2

Calculate Current Assets

Inventory (₦350,000) + Trade Debtors (₦180,000) + Cash at Bank (₦120,000) = ₦650,000

Sum all short-term liquid assets.

3

Calculate Current Liabilities

Trade Creditors (₦220,000) + Accrued Expenses (₦30,000) = ₦250,000

Sum all short-term obligations.

4

Calculate Working Capital

Current Assets (₦650,000) - Current Liabilities (₦250,000) = ₦400,000

Working capital is net short-term asset position.

5

Calculate Capital Employed

Fixed Assets (₦1,850,000) + Working Capital (₦400,000) = ₦2,250,000

Capital employed represents total net assets invested in the enterprise.

Key Concept

Capital Employed Calculation

Estimated Time:1m 30s

Question 6684Question →

A $5.00\text{ g}$ sample of hydrated copper(II) tetraoxosulfate(VI), $\text{CuSO}_4 \cdot x\text{H}_2\text{O}$ , was heated strongly in a crucible until all water of crystallization was driven off, leaving an anhydrous residue of mass $3.20\text{ g}$ . What is the value of $x$ in the formula of the hydrated salt? $[\text{Cu} = 64, \text{S} = 32, \text{O} = 16, \text{H} = 1]$

2

3

5

10

Show answer & explanation

Answer: $5$

Answer

The value of

x

in the hydrated salt formula is

5

.

Heating the hydrated salt drives off all water of crystallization. The mass of water lost is

5.00\text{ g} - 3.20\text{ g} = 1.80\text{ g}

. Converting both the anhydrous salt (

3.20\text{ g}

) and water (

1.80\text{ g}

) to moles using their respective molar masses (

160\text{ g/mol}

and

18\text{ g/mol}

) yields

0.020\text{ mol}

of

\text{CuSO}_4

and

0.100\text{ mol}

of

\text{H}_2\text{O}

. The mole ratio

0.100 / 0.020

simplifies to

5

, making

5

the correct value for

x

.

Step-by-Step Solution

1

Calculate the mass of water of crystallization driven off.

\text{Mass of H}_2\text{O} = 5.00\text{ g} - 3.20\text{ g} = 1.80\text{ g}

The loss in mass upon heating equals the mass of water lost from the hydrated salt.

2

Determine the molar masses of anhydrous

\text{CuSO}_4

and

\text{H}_2\text{O}

.

M(\text{CuSO}_4) = 64 + 32 + (4 \times 16) = 160\text{ g/mol}

and

M(\text{H}_2\text{O}) = (2 \times 1) + 16 = 18\text{ g/mol}

Molar masses are required to convert the masses of salt and water into mole amounts.

3

Calculate the number of moles of anhydrous

\text{CuSO}_4

and

\text{H}_2\text{O}

.

n(\text{CuSO}_4) = \frac{3.20}{160} = 0.020\text{ mol}

and

n(\text{H}_2\text{O}) = \frac{1.80}{18} = 0.100\text{ mol}

Moles are obtained by dividing mass by molar mass (

n = m / M

).

4

Determine the stoichiometric ratio

x = \frac{n(\text{H}_2\text{O})}{n(\text{CuSO}_4)}

.

x = \frac{0.100\text{ mol}}{0.020\text{ mol}} = 5

The mole ratio gives the number of water molecules of crystallization bound per mole of anhydrous salt.

Key Concept

Determination of Water of Crystallization by Gravimetric Analysis

Question 6685Question →

Read the prose extract below:

"As the drought worsened, the old village chief looked at his parched fields and declared to his council that a leader must lose his life to truly save it, and that their present poverty was their greatest wealth."

Which literary device is prominently demonstrated in the chief's declaration?

Paradox

Oxymoron

Metaphor

Assonance

Show answer & explanation

Answer: Paradox

Answer

The literary device prominently demonstrated in the chief's declaration is Paradox.

The expression presents a complete statement ('a leader must lose his life to truly save it') that seems logically contradictory at first glance, but conveys a deeper philosophical truth about leadership and self-sacrifice. This structural and thematic contradiction is the definition of a paradox.

Step-by-Step Solution

1

Analyze the chief's declaration in the prose extract.

The statement asserts that 'a leader must lose his life to truly save it' and 'their present poverty was their greatest wealth.'

Identifying the key stylistic construction is essential to classifying the literary device.

2

Evaluate the relationship between the ideas presented in the assertion.

The claims seem contradictory and logically impossible on a literal level, yet they convey a profound philosophical truth regarding sacrifice and resilience.

Distinguishing between superficial contradiction and deeper thematic truth is the defining characteristic of a paradox.

3

Differentiate paradox from related literary terms such as oxymoron.

While an oxymoron juxtaposes contradictory terms side by side (e.g., 'painful pleasure'), a paradox spans a full clause or sentence expressing a complex truth.

This confirms that the device used across the full sentence structure is a paradox.

Key Concept

Literary Devices in Prose: Paradox vs. Oxymoron

Estimated Time:1m 0s

Question 6686Question →

Read the following dialogue snippet from a dramatic text:

LEAD CHARACTER: I shall press forward with my ambition, regardless of the divine portents or the warnings of the elders!
COMPANION: Yet consider the modesty of our origins and the peril of defying the decrees of heaven; true wisdom lies in moderation.

In this dramatic interaction, how does the companion function as a character type?

tragic hero whose internal flaw drives the central dramatic crisis

foil whose cautious attitude accentuates the lead character's hubris

antagonist who directly opposes and plots against the lead character

stock character designed primarily to provide lighthearted comic relief

Show answer & explanation

Answer: foil whose cautious attitude accentuates the lead character's hubris

Answer

foil whose cautious attitude accentuates the lead character's hubris

In dramatic literature, a foil is a character whose qualities contrast sharply with those of another character (usually the protagonist) to highlight specific traits. Here, the companion's cautious and moderate posture directly accentuates the lead character's excessive ambition and hubris.

Step-by-Step Solution

1

Analyze the dialogue of both characters in the excerpt.

The lead character expresses excessive pride and disregard for warnings (hubris), while the companion advocates moderation and respect for divine order.

Character types are determined by their dramatic function and relation to other figures in the scene.

2

Determine the structural relationship between the lead character and the companion.

By juxtaposing the companion's restraint against the lead character's arrogance, the playwright sharpens the audience's perception of the lead character's tragic trait.

A character who highlights another character's traits through direct contrast functions as a foil.

Key Concept

Character Foil in Drama

Estimated Time:1m 0s

Question 6687Question →

Match each wave phenomenon on the left with its accurate wave classification and propagation mechanism on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Sound waves in air correspond to longitudinal mechanical waves requiring a material medium. Light waves traveling through a vacuum correspond to transverse electromagnetic waves needing no material medium. Ripples on a stretched string correspond to transverse mechanical waves with perpendicular particle vibration. Primary seismic P-waves correspond to longitudinal body waves with parallel particle movement.

Sound in air and seismic P-waves are longitudinal mechanical waves because medium particles vibrate parallel to the direction of propagation. Light is a transverse electromagnetic wave because it propagates via perpendicular field oscillations without needing a material medium. Waves on a string are transverse mechanical waves because string segments vibrate perpendicular to the length of the string.

Step-by-Step Solution

1

Analyze medium dependence

Sound, string waves, and seismic P-waves require a material medium (mechanical waves), whereas light waves travel through a vacuum (electromagnetic waves).

Waves are broadly categorized as mechanical or non-mechanical (electromagnetic) based on whether they require a physical medium for propagation.

2

Analyze particle motion relative to wave propagation

Sound and P-waves oscillate parallel to propagation (longitudinal); light waves and string vibrations oscillate perpendicular to propagation (transverse).

Direction of medium displacement relative to energy transmission determines whether a wave is transverse or longitudinal.

3

Match each physical scenario to its unique classification pair

Match sound wave to longitudinal mechanical, light to transverse electromagnetic, string wave to transverse mechanical, and seismic P-wave to longitudinal body wave.

Synthesize medium dependence and displacement direction for each specific physical system.

Key Concept

Classification of waves based on material medium dependence (mechanical vs. electromagnetic) and particle oscillation direction (transverse vs. longitudinal).

Question 6688Question →

A galvanometer has an internal resistance of $20\text{ }\Omega$ and produces a full-scale deflection for a current of $15\text{ mA}$ . What resistance of the multiplier, in ohms ( $\Omega$ ), is required to convert this galvanometer into a voltmeter capable of measuring a maximum potential difference of $30\text{ V}$ ?

Show answer & explanation

Answer: 1980

Answer

The required multiplier resistance is

1980\text{ }\Omega

.

To convert a galvanometer into a voltmeter, a multiplier resistor

R_m

is connected in series. The maximum potential difference

V

across the combination is given by

V = I_g(R_g + R_m)

. Substituting

V = 30\text{ V}

,

I_g = 0.015\text{ A}

, and

R_g = 20\text{ }\Omega

yields

R_m = 1980\text{ }\Omega

.

Step-by-Step Solution

1

Convert current from milliamperes to amperes.

I_g = 15\text{ mA} = 0.015\text{ A}

.

Standard electrical formulas require current in amperes.

2

Apply the relationship between voltage range, galvanometer current, internal resistance, and multiplier resistance.

V = I_g(R_g + R_m)

, where

V = 30\text{ V}

,

I_g = 0.015\text{ A}

, and

R_g = 20\text{ }\Omega

.

A multiplier resistor is connected in series with the galvanometer so that the total potential difference is distributed across both components.

3

Rearrange the equation and compute

R_m

.

R_m = \frac{30}{0.015} - 20 = 2000 - 20 = 1980\text{ }\Omega

.

Subtracting the internal resistance of the galvanometer from the total required resistance yields the necessary multiplier resistance.

Key Concept

Galvanometer conversion to a voltmeter using a series multiplier resistor

Estimated Time:1m 30s

Question 6689Question →

A laboratory mixture consists of an organic solute dissolved in water. A chemist decides to isolate the organic solute by solvent extraction using ethoxyethane (diethyl ether). Arrange the following procedural steps in the correct logical sequence from first to last to complete this separation using a separating funnel.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct logical sequence is: first, close the stopcock and introduce the aqueous mixture and ethoxyethane into the funnel; second, stopper, invert, shake, and periodically vent internal pressure; third, mount the funnel on a stand and allow the immiscible layers to settle completely; fourth, remove the stopper and carefully drain the lower aqueous layer followed by collecting the upper organic layer.

The correct procedural order follows standard chemical laboratory protocol: loading reagents, mixing/partitioning with pressure venting, phase settling via density separation, and step-by-step draining under atmospheric pressure.

Step-by-Step Solution

1

Ensure the stopcock is closed and add both liquid phases into the separating funnel.

Both liquids are safely contained inside the funnel without draining prematurely.

Solvent extraction requires bringing the solute-containing mixture into contact with the extraction solvent.

2

Stopper the funnel, invert it, shake thoroughly, and open the stopcock repeatedly while inverted.

Interfacial contact area is maximized for solute partitioning, and excess vapor pressure is safely released.

Agitation allows the solute to dissolve into the organic phase, while venting avoids dangerous pressure buildup from volatile solvents.

3

Place the funnel back on a retort stand and let it rest undisturbed.

The mixture separates into two distinct liquid layers based on density and immiscibility.

Static resting is necessary for the dispersed droplets of the two immiscible liquids to coalesce into continuous phases.

4

Unstopper the funnel and open the stopcock to drain the bottom aqueous layer into a flask, then separate the upper ethoxyethane layer.

The two liquids are cleanly separated into individual collection vessels.

Unstoppering equalizes atmospheric pressure to prevent a vacuum lock during draining.

Key Concept

Solvent Extraction and Separating Funnel Manipulation

Question 6690Question →

Arrange the following atomic subshells in order of increasing energy according to the Aufbau principle ( $(n+l)$ rule):

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct order of increasing orbital energy is

3s \rightarrow 3p \rightarrow 4s \rightarrow 3d

.

By applying the

(n+l)

rule (Madelung's rule) derived from the Aufbau principle, subshells fill in order of increasing

(n+l)

energy sum. Calculating these values yields:

3s

(

3+0=3

),

3p

(

3+1=4

),

4s

(

4+0=4

), and

3d

(

3+2=5

). For subshells with equal sums (

3p

and

4s

), the one with the smaller principal quantum number

n

is lower in energy (

3p

with

n=3

is lower than

4s

with

n=4

). Therefore, the correct sequence from lowest to highest energy is

3s \rightarrow 3p \rightarrow 4s \rightarrow 3d

.

Step-by-Step Solution

1

Determine the

(n+l)

value for each subshell

For

3s

:

3+0 = 3

. For

3p

:

3+1 = 4

. For

4s

:

4+0 = 4

. For

3d

:

3+2 = 5

.

According to the Aufbau principle and the

(n+l)

rule, orbitals fill in order of increasing

(n+l)

energy values.

2

Compare subshells with identical

(n+l)

values

Both

3p

and

4s

have

(n+l) = 4

. Since

3p

has a smaller principal quantum number (

n=3

compared to

n=4

),

3p

is lower in energy than

4s

.

When two orbitals have the same

(n+l)

value, the orbital with the lower principal quantum number

n

has lower energy.

3

Sequence the subshells from lowest to highest energy

The final sequence is

3s < 3p < 4s < 3d

.

Sorting by

(n+l)

sum first, then by

n

value for ties, yields the correct Aufbau order.

Key Concept

Aufbau Principle and the (n+l) Rule

Question 6691Question →

An inclined plane is set at an angle of $30^\circ$ to the horizontal. An effort of $320\text{ N}$ applied parallel to the plane is used to push a load of $480\text{ N}$ up the incline at a constant speed. What is the efficiency of the inclined plane expressed as a percentage?

Show answer & explanation

Answer: 75%; 75; 75 percent

Answer

The efficiency of the inclined plane is

75\%

.

For an inclined plane inclined at

30^\circ

to the horizontal, the velocity ratio (VR) is given by

\text{VR} = \frac{1}{\sin 30^\circ} = 2

. The mechanical advantage (MA) is

\text{MA} = \frac{\text{Load}}{\text{Effort}} = \frac{480\text{ N}}{320\text{ N}} = 1.5

. Dividing MA by VR and multiplying by

100\%

yields an efficiency of

\left(\frac{1.5}{2}\right) \times 100\% = 75\%

.

Step-by-Step Solution

1

Determine the Velocity Ratio (VR) of the inclined plane from its angle of inclination

VR = \frac{1}{\sin 30^\circ} = \frac{1}{0.5} = 2

For an inclined plane with inclination angle \theta, the velocity ratio is equal to \frac{1}{\sin \theta}.

2

Calculate the Mechanical Advantage (MA)

MA = \frac{\text{Load}}{\text{Effort}} = \frac{480\text{ N}}{320\text{ N}} = 1.5

Mechanical advantage is defined as the ratio of load to effort force.

3

Calculate the efficiency of the machine

\text{Efficiency} = \frac{\text{MA}}{\text{VR}} \times 100\% = \frac{1.5}{2} \times 100\% = 75\%

Efficiency is the ratio of mechanical advantage to velocity ratio expressed as a percentage.

Key Concept

Efficiency of an Inclined Plane

Question 6692Question →

A major feature that distinguishes a department store from a chain store (multiple shops) is that a department store

operates under one roof with distinct sections specializing in different lines of goods.

sells a single line of standardized merchandise across numerous branch locations.

derives cost reductions solely from industry-wide localization rather than internal scale.

bypasses the wholesaler strictly to act as a primary agricultural producer.

Show answer & explanation

Answer: operates under one roof with distinct sections specializing in different lines of goods.

Answer

Operating under one roof with distinct sections specializing in different lines of goods is the defining feature of a department store.

Department stores are large-scale retail businesses organized into distinct departments in a single building, offering a wide assortment of merchandise under one roof. In contrast, chain stores consist of multiple retail outlets located in different areas owned by a single firm, usually specializing in one line of products.

Step-by-Step Solution

1

Identify the defining structural characteristics of a department store.

Department stores consist of multiple departments under one roof, each operating as a specialized unit for a specific commodity line.

This single-location, multi-department structure contrasts with chain stores which operate identical branches in different geographical locations.

2

Compare department store features with chain store features.

Chain stores specialize in a single line or narrow range of goods across multiple geographic branches, whereas department stores offer wide variety under one roof.

This structural difference isolates the core distinguishing feature between the two large-scale retail formats.

Key Concept

Distinguishing Features of Large-Scale Retail Outlets

Question 6693Question →

What is the total number of ions present in a $9.5\text{ g}$ sample of pure magnesium chloride ( $\text{MgCl}_2$ )? $[\text{Mg} = 24, \text{Cl} = 35.5, N_A = 6.02 \times 10^{23}\text{ mol}^{-1}]$

1.81 \times 10^{23}

6.02 \times 10^{22}

1.20 \times 10^{23}

2.24 \times 10^{23}

Show answer & explanation

Answer: $1.81 \times 10^{23}$

Answer

1.81 \times 10^{23}

ions

The sample contains

0.1\text{ mol}

of

\text{MgCl}_2

. Because each formula unit of

\text{MgCl}_2

dissociates into 3 ions (

1\text{ Mg}^{2+}

and

2\text{ Cl}^-

), there are

0.3\text{ mol}

of total ions. Multiplying

0.3\text{ mol}

by Avogadro's constant (

6.02 \times 10^{23}

) yields

1.81 \times 10^{23}

ions.

Step-by-Step Solution

1

Calculate the molar mass of magnesium chloride (

\text{MgCl}_2

)

Molar mass

= 24 + 2(35.5) = 95\text{ g/mol}

Molar mass is required to convert the given mass into moles.

2

Determine the number of moles of

\text{MgCl}_2

in

9.5\text{ g}

Moles

= 9.5\text{ g} / 95\text{ g/mol} = 0.1\text{ mol}

Applying the mole formula:

\text{moles} = \text{mass} / \text{molar mass}

.

3

Determine the total moles of ions released upon dissociation

\text{MgCl}_2 \rightarrow \text{Mg}^{2+} + 2\text{Cl}^-

, giving 3 moles of ions per mole of salt. Total ion moles

= 0.1 \times 3 = 0.3\text{ mol}

Each formula unit of magnesium chloride contains one magnesium ion and two chloride ions.

4

Calculate the total number of individual ions using Avogadro's constant

Total ions

= 0.3 \times 6.02 \times 10^{23} = 1.806 \times 10^{23} \approx 1.81 \times 10^{23}

ions

Multiplying the total moles of ions by Avogadro's constant yields particle count.

Key Concept

The Mole Concept and Avogadro's Constant applied to Ionic Dissociation

Estimated Time:1m 30s

Question 6694Question →

The transformation of iron(II) ions to iron(III) ions in aqueous solution is represented by the ionic half-equation:

\text{Fe}^{2+}_{(aq)} \rightarrow \text{Fe}^{3+}_{(aq)} + e^-

Which of the following statements correctly explains this chemical change in terms of classical and modern redox concepts?

It is an oxidation process because iron(II) loses an electron, resulting in an increase in oxidation state from

+2

to

+3

, which expands beyond classical oxygen-addition definitions.

It is a reduction process because iron(II) loses a negatively charged electron, which decreases its net oxidation state.

It is an oxidation process because uncombined elemental iron must be formed with a non-zero oxidation state before becoming iron(III).

It is a reduction process because classical redox definitions require the addition of oxygen atoms for any oxidation to take place.

Show answer & explanation

Answer: It is an oxidation process because iron(II) loses an electron, resulting in an increase in oxidation state from $+2$ to $+3$ , which expands beyond classical oxygen-addition definitions.

Answer

The transformation is an oxidation process because iron(II) loses an electron, resulting in an increase in its oxidation number from

+2

to

+3

.

The correct option accurately applies the modern definition of redox. Loss of electrons (

e^-

) increases the charge/oxidation state of iron from

+2

to

+3

, which defines oxidation regardless of whether oxygen is present.

Step-by-Step Solution

1

Analyze the given ionic half-equation

Iron(II) ion (

\text{Fe}^{2+}

) releases one electron (

e^-

) to become iron(III) ion (

\text{Fe}^{3+}

).

Determining electron movement is key to applying modern redox definitions.

2

Apply modern redox definitions (electron transfer and oxidation number)

Loss of electrons corresponds to oxidation. The oxidation number increases from

+2

to

+3

.

By definition, oxidation is loss of electrons (OIL) and increase in oxidation state.

3

Compare with classical redox definitions

Classical definitions restricted oxidation to oxygen gain or hydrogen loss, whereas modern electron theory accounts for ion conversions without oxygen.

Modern definitions generalize redox behavior to non-oxygen reactions.

Key Concept

Modern vs Classical Redox Concepts: Oxidation as Electron Loss and Oxidation State Increase

Question 6695Question →

Match each corporate security or stock market concept associated with a Public Limited Company on the left with its defining legal or financial characteristic on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Ordinary Shares match equity capital with variable dividends and voting rights; Cumulative Preference Shares match entitlement to carried-forward unpaid dividend arrears; Debentures match long-term loan capital with fixed interest paid to creditors; Stock Exchange Listing matches formal admission of corporate securities to public trading.

Ordinary shares grant variable dividends and voting privileges. Cumulative preference shares guarantee that missed dividends carry forward to future years. Debentures are loan certificates earning fixed interest. Stock listing enables formal public trading of company securities on the stock market.

Step-by-Step Solution

1

Analyze Ordinary Shares

Ordinary shares represent equity capital bearing variable dividends depending on profits, carrying ultimate risk and voting control.

Equity holders are residual owners of the business.

2

Analyze Cumulative Preference Shares

Unpaid fixed dividends in lean financial years accumulate as arrears and must be settled in subsequent profitable years before equity dividends.

The cumulative feature protects preference share dividend claims across financial periods.

3

Analyze Debentures

Debentures represent borrowed debt capital providing fixed interest regardless of company profits, creating a creditor relationship.

Debentures are loan certificates, not equity ownership shares.

4

Analyze Stock Exchange Listing

Listing refers to the official quote and admission of public limited company shares to public trading on the stock exchange.

Public companies must meet strict stock market listing requirements to facilitate public share trading.

Key Concept

Characteristics of Public Limited Company Securities and Stock Listing Requirements

Question 6696Question →

A resistance thermometer has a resistance of $5.0\,\Omega$ at $0^\circ\text{C}$ and $5.8\,\Omega$ at $40^\circ\text{C}$ . What is the temperature coefficient of resistance of the material in $\text{K}^{-1}$ ?

Show answer & explanation

Answer: 0.004

Answer

The temperature coefficient of resistance of the material is

0.004\,\text{K}^{-1}

(or

4.0 \times 10^{-3}\,\text{K}^{-1}

).

The temperature coefficient of resistance is calculated using

\alpha = \frac{R_T - R_0}{R_0 \Delta T}

. Substituting

R_0 = 5.0\,\Omega

,

R_T = 5.8\,\Omega

, and

\Delta T = 40\,\text{K}

yields

\alpha = \frac{0.8}{200} = 0.004\,\text{K}^{-1}

.

Step-by-Step Solution

1

Identify the relationship between resistance and temperature.

R_T = R_0(1 + \alpha \Delta T)

, with

R_0 = 5.0\,\Omega

,

R_T = 5.8\,\Omega

, and

\Delta T = 40^\circ\text{C}

.

The resistance of metallic conductors varies linearly with temperature for moderate temperature changes.

2

Rearrange the expression to isolate the temperature coefficient

\alpha

.

\alpha = \frac{R_T - R_0}{R_0 \Delta T}

Isolating

\alpha

allows direct computation from the given resistance values and temperature interval.

3

Calculate the numerical value of

\alpha

.

\alpha = \frac{5.8 - 5.0}{5.0 \times 40} = \frac{0.8}{200} = 0.004\,\text{K}^{-1}

Dividing the change in resistance by the product of initial resistance and temperature change gives the fractional resistance change per unit temperature change.

Key Concept

Temperature dependence of electrical resistance and temperature coefficient of resistance.

Question 6697Question →

Match each credit instrument or form of credit listed in Column A with its corresponding legal feature or operational description in Column B.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The correct pairings are: Bill of Exchange corresponds to the unconditional order in writing addressed by a creditor to a debtor; Promissory Note corresponds to the unconditional written promise made by a debtor to pay a creditor; Letter of Credit corresponds to the financial document issued by a bank guaranteeing payment in foreign trade; and Hire Purchase corresponds to the credit trading system where legal title remains with the seller until the final instalment is paid.

Each instrument and form of credit is matched to its essential legal definition: a Bill of Exchange is an order drawn by a creditor instructing payment; a Promissory Note is a promise issued by a debtor to pay; a Letter of Credit is a bank guarantee supporting international trade; and Hire Purchase restricts legal ownership transfer until the completion of all agreed instalments.

Step-by-Step Solution

1

Analyze the operational mechanism of a Bill of Exchange.

Identify it as an order to pay drawn by the creditor.

A bill of exchange involves three parties where the drawer orders the drawee to pay a specified sum.

2

Analyze the operational mechanism of a Promissory Note.

Identify it as a promise to pay made by the debtor.

A promissory note involves two primary parties where the maker promises payment to the payee.

3

Analyze the function of a Letter of Credit in commercial transactions.

Identify it as a bank guarantee facilitating international trade.

The importer's bank issues this document to guarantee payment to the exporter upon presentation of shipping documents.

4

Distinguish legal ownership transfer under Hire Purchase.

Identify that title stays with the vendor until the final instalment.

Unlike standard deferred payment or credit sales, hire purchase retains ownership with the seller while granting immediate physical possession to the buyer.

Key Concept

Forms and Instruments of Credit

Question 6698Question →

Unlike department stores, which operate multiple distinct sections selling diverse categories of goods under a single roof, multiple shops (chain stores) consist of numerous branch outlets under centralized management that specialize in selling a standardized line of similar merchandise.

True

False

Show answer & explanation

Answer: True

Answer

The statement is True. Department stores offer a wide range of product lines divided into departments under one roof, whereas multiple shops (chain stores) operate scattered branch outlets selling a standardized or uniform range of products under centralized control.

The statement accurately differentiates between two major forms of large-scale retailing. Department stores feature decentralized product departments under one roof, whereas chain stores feature decentralized locations with a centralized, uniform product offering.

Step-by-Step Solution

1

Analyze the operational structure of a department store

A department store is a large retail establishment divided into distinct departments (e.g., clothing, electronics, cosmetics), offering wide product variety under one roof.

Understanding the physical setup and product variety of department stores establishes the baseline for comparison.

2

Analyze the operational structure of multiple shops (chain stores)

Chain stores consist of multiple retail outlets located in different areas, controlled by a head office, selling similar or standardized goods (e.g., shoe chains, book chains).

Identifying the multi-branch and specialized nature of chain stores highlights their distinction from single-roof multi-department stores.

3

Compare the two retail formats against the given statement

The statement correctly contrasts the single-roof departmentalized structure of department stores with the multi-location specialized product structure of chain stores.

Confirming the accuracy of the comparison determines the true/false evaluation.

Key Concept

Distinction between Department Stores and Multiple Shops (Chain Stores)

Question 6699Question →

Match each poetic structural form on the left with its correct structural description on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Villanelle pairs with the 19-line fixed form with two refrains; Sestina pairs with the 39-line unrhymed form featuring rotating end-words; Terza Rima pairs with interlocking tercets rhyming aba bcb cdc; Ottava Rima pairs with the eight-line stanza rhyming abababcc.

Each poetic structural term is matched to its definitive organizational traits: the Villanelle by its 19-line two-refrain structure, the Sestina by its 39-line end-word rotation pattern, Terza Rima by its interlocking aba bcb tercets, and Ottava Rima by its eight-line abababcc stanzaic organization.

Step-by-Step Solution

1

Analyze the line count and refrain structure of fixed poetic forms.

Identify that 19 lines with five tercets and one quatrain defines a Villanelle, while 39 lines with rotating end-words defines a Sestina.

Line count and refrain patterns are the defining structural features of these French and Provençal fixed forms.

2

Examine the stanzaic rhyme patterns of the remaining forms.

Identify that interlocking tercets (aba bcb cdc) corresponds to Terza Rima, while an eight-line stanza rhyming abababcc corresponds to Ottava Rima.

Terza rima relies on chain-rhyming across tercets, whereas ottava rima is a discrete eight-line stanza closing with a rhyming couplet.

Key Concept

Poetic Structure and Fixed Forms

Estimated Time:1m 30s

Question 6700Question →

Match each prose extract below to the dominant literary device or stylistic technique it demonstrates.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The extract describing the river roaring like a beast matches Simile; the extract mentioning cruel kindness matches Oxymoron; the extract describing the wardrobe guarding secrets matches Personification; and the extract stating a reminder was given a thousand times matches Hyperbole.

Each prose extract demonstrates a specific figurative device based on its structural elements: explicit comparative word 'like' indicates a simile; adjacent opposite words indicate an oxymoron; non-human object performing human action indicates personification; and deliberate quantitative exaggeration indicates hyperbole.

Step-by-Step Solution

1

Examine extract 1: 'The river rushed through the narrow gorge, roaring like a caged beast desperate for freedom.'

Identified explicit comparison using the connector 'like'.

A direct comparison using 'like' or 'as' is the defining characteristic of a simile.

2

Examine extract 2: 'The warden offered the prisoner a cruel kindness...'

Identified side-by-side placement of opposing terms ('cruel' and 'kindness').

Juxtaposing two contradictory words in a single phrase forms an oxymoron.

3

Examine extract 3: 'The ancient mahogany wardrobe stood silent in the corner, guarding the forgotten secrets...'

Identified human behavior attributed to a non-human item.

Giving human characteristics or actions (guarding secrets) to an object (wardrobe) is personification.

4

Examine extract 4: 'The merchant reminded his stubborn apprentice a thousand times...'

Identified deliberate overstatement for effect.

Exaggerating an action's frequency to an extreme degree ('a thousand times') creates hyperbole.

Key Concept

Literary Devices and Figurative Diction in Prose

Answer

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