Tüm alıştırma soruları

Soru 3201Soru →

A geologist analyzes a cross-section of undisturbed sedimentary rock containing three horizontal layers: shale at the bottom, sandstone in the middle, and limestone at the top. A vertical basalt dike cuts through both the shale and sandstone layers, but terminates directly beneath the limestone layer. Based on relative dating principles, which of the following statements correctly describes the relative age of the basalt dike?

It is older than both the shale and sandstone layers because igneous magma originates from deep below the crust.

It is younger than the sandstone layer but older than the limestone layer.

It is younger than the limestone layer because igneous intrusions always postdate every sedimentary layer in a formation.

It is the exact same age as the limestone layer because igneous intrusions and overlying strata solidify simultaneously.

Cevabı ve açıklamayı göster

Cevap: It is younger than the sandstone layer but older than the limestone layer.

Cevap

The basalt dike is younger than the sandstone layer but older than the limestone layer.

According to the principle of cross-cutting relationships, an igneous intrusion is younger than any rock layers it cuts through. Because the basalt dike cuts through the shale and sandstone, it is younger than both of those units. Furthermore, because the dike does not penetrate the limestone layer above it, the limestone must have been deposited on top of the eroded dike at a later time, making the dike older than the limestone.

Adım Adım Çözüm

1

Apply the Principle of Cross-Cutting Relationships to the penetrated layers

The basalt dike is younger than both the shale and sandstone layers.

A geologic feature (such as an igneous intrusion or fault) that cuts across rock layers must be younger than the rocks it disrupts.

2

Apply the Law of Superposition to the unpenetrated overlying layer

The limestone layer is younger than the basalt dike.

Because the basalt dike stops beneath the limestone and does not alter or cut it, the limestone was deposited horizontally on top after the dike intruded and cooled.

3

Synthesize the chronological sequence

Chronological order from oldest to newest: Shale

\rightarrow

Sandstone

\rightarrow

Basalt Dike

\rightarrow

Limestone.

Combining relative dating principles places the dike between the deposition of the sandstone and the limestone.

Anahtar Kavram

Principle of Cross-Cutting Relationships and the Law of Superposition in Relative Dating

Tahmini Süre:1m 0s

Soru 3202Soru →

An atom is composed of a central core and surrounding subatomic particles. Match each atomic structure component on the left with its defining physical property and role on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Proton matches with the positively charged particle defining atomic number; Neutron matches with the neutral particle in the nucleus contributing to mass; Electron matches with the negatively charged particle orbiting outside the nucleus; Atomic nucleus matches with the dense central core containing nearly all atomic mass.

Each subatomic entity is matched according to its fundamental physical characteristics: protons are positively charged and determine atomic number; neutrons are uncharged nucleons that contribute to mass number; electrons are negative particles that orbit the nucleus; and the nucleus is the dense core where nearly all atomic mass is located.

Adım Adım Çözüm

1

Identify the charge, location, and function of a proton

Protons are positively charged (

+1

) nucleons whose count equals the atomic number (

Z

).

Every unique chemical element is defined by its unique number of protons.

2

Identify the charge, location, and function of a neutron

Neutrons are neutral (

0

charge) nucleons that contribute to the atom's total mass number (

A

).

Neutrons provide nuclear stability and mass without affecting net nuclear charge.

3

Identify the charge, location, and function of an electron

Electrons are negatively charged (

-1

) particles located in electron shells surrounding the nucleus.

Electrons balance positive nuclear charge in neutral atoms and determine bonding behavior.

4

Identify the structural definition and mass distribution of the atomic nucleus

The atomic nucleus is the dense central region containing all protons and neutrons.

Because protons and neutrons are roughly

1836

times more massive than electrons, nearly all mass is located at the center.

Anahtar Kavram

Subatomic particle properties, charges, and atomic architecture

Tahmini Süre:45s

Soru 3203Soru →

When clear aqueous solutions of silver nitrate (

AgNO_3

) and sodium chloride (

NaCl

) are mixed, an insoluble white solid of silver chloride (

AgCl

) immediately forms and precipitates out of the solution, leaving dissolved sodium nitrate (

NaNO_3

):

AgNO_3 + NaCl \rightarrow AgCl + NaNO_3

Which type of chemical reaction is represented by this process?

Single replacement reaction

Double replacement reaction

Decomposition reaction

Physical phase change

Cevabı ve açıklamayı göster

Cevap: Double replacement reaction

Cevap

Double replacement reaction

In a double replacement (or double displacement) reaction, two ionic compounds in aqueous solution exchange partner ions to form two new compounds. Here, silver cations (

Ag^+

) combine with chloride anions (

Cl^-

) to form an insoluble solid precipitate of silver chloride (

AgCl

), while sodium ions (

Na^+

) and nitrate ions (

NO_3^-

) remain in solution as sodium nitrate (

NaNO_3

).

Adım Adım Çözüm

1

Analyze the reactants and products in the chemical equation.

The reaction begins with two aqueous ionic compounds, silver nitrate (

AgNO_3

) and sodium chloride (

NaCl

), and produces two distinct compounds, solid silver chloride (

AgCl

) and aqueous sodium nitrate (

NaNO_3

).

Identifying the number and chemical nature of reactant and product species is essential to determining the reaction archetype.

2

Track how the ions rearrange during the reaction.

The silver cation (

Ag^+

) switches partners from nitrate (

NO_3^-

) to chloride (

Cl^-

), while the sodium cation (

Na^+

) switches from chloride to nitrate.

Observing a mutual exchange of ion partners between two compounds confirms that an ion-exchange process has taken place.

3

Match the observed ion exchange with standard chemical reaction classifications.

A reaction of the general form

AB + CD \rightarrow AD + CB

in which two ionic compounds exchange ions to form a precipitate is classified as a double replacement (double displacement) reaction.

Classifying the reaction distinguishes it from synthesis, decomposition, single replacement, and physical state transitions.

Anahtar Kavram

Double replacement reactions occur when the cations and anions of two aqueous ionic compounds exchange places, frequently driven by the formation of an insoluble solid precipitate, a gas, or water.

Tahmini Süre:1m 0s

Soru 3204Soru →

A materials technician is evaluating the fundamental characteristics of several substances used in mechanical systems. Match each material property with its correct scientific definition.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Ductility matches the ability of a solid to be drawn into wires under tensile stress; Viscosity matches the internal resistance of a fluid to flow; Flammability matches the chemical capacity of a substance to ignite and combust; Solubility matches the capacity of a solute to dissolve in a solvent.

Each property is accurately paired with its distinct physical or chemical behavior: ductility refers to tensile elongation into wire, viscosity measures fluid friction against flow, flammability measures chemical reactivity in combustion, and solubility determines dissolution capacity in a solvent.

Adım Adım Çözüm

1

Identify mechanical physical properties of solids

Ductility represents tensile deformation into wires, distinguishing it from malleability (hammering into sheets).

Tensile stress applied to ductile metals allows elongation without brittle fracture.

2

Identify fluid transport physical properties

Viscosity represents fluid shear resistance and thickness.

Internal intermolecular friction governs how quickly or slowly fluids like motor oil or water flow.

3

Differentiate chemical properties from physical properties

Flammability involves chemical transformation through combustion.

Burning produces new chemical substances (carbon dioxide, water vapor, ash), making flammability a chemical property.

4

Identify mixture and dissolution characteristics

Solubility represents the maximum solute concentration in a solvent without altering chemical identities.

Dissolving is a physical process where solute particles disperse evenly within solvent molecules.

Anahtar Kavram

Classification and definitions of characteristic physical and chemical properties of matter

Tahmini Süre:1m 0s

Soru 3205Soru →

A $400\text{ kg}$ patrol boat accelerates uniformly from rest to a speed of $18\text{ m/s}$ in $6\text{ seconds}$ across calm water. If a constant hydrodynamic resistance force of $300\text{ N}$ opposes the motion, what forward thrust force must the boat's engine produce?

1,200\text{ N}

1,500\text{ N}

900\text{ N}

4,200\text{ N}

Cevabı ve açıklamayı göster

Cevap: $1,500\text{ N}$

Cevap

The boat's engine must produce a forward thrust of

1,500\text{ N}

.

To find the total thrust, first determine the acceleration from the velocity change (

18\text{ m/s} \div 6\text{ s} = 3\text{ m/s}^2

). Using Newton's Second Law (

F = ma

), the net forward force required is

400\text{ kg} \times 3\text{ m/s}^2 = 1,200\text{ N}

. Because

300\text{ N}

of water resistance opposes the boat, the engine must supply enough forward force to overcome drag plus provide the net accelerating force:

1,200\text{ N} + 300\text{ N} = 1,500\text{ N}

.

Adım Adım Çözüm

1

Calculate the acceleration of the patrol boat using kinematic relations.

a = \frac{v_f - v_i}{t} = \frac{18\text{ m/s} - 0\text{ m/s}}{6\text{ s}} = 3\text{ m/s}^2

Uniform acceleration is defined as the change in velocity divided by the elapsed time.

2

Determine the net horizontal force required to accelerate the boat using Newton's Second Law.

F_{\text{net}} = m \cdot a = 400\text{ kg} \times 3\text{ m/s}^2 = 1,200\text{ N}

The net force acting on any mass is directly proportional to its acceleration (

F = ma

).

3

Apply the net force equation along the horizontal axis to solve for engine thrust.

F_{\text{thrust}} - F_{\text{resistance}} = F_{\text{net}} \implies F_{\text{thrust}} = 1,200\text{ N} + 300\text{ N} = 1,500\text{ N}

The engine thrust must overcome the backward resistive drag while providing the remaining force needed for forward acceleration.

Anahtar Kavram

Newton's Second Law and Net Force in One Dimension

Tahmini Süre:1m 0s

Soru 3206Soru →

A quartermaster is distributing supplies to a unit. The unit requires $4\frac{3}{4}$ pallets of rations. If $2\frac{1}{4}$ pallets have already been delivered, how many more pallets are needed?

Cevabı ve açıklamayı göster

Cevap: 2.5

Cevap

2.5

To find how many more pallets are needed, subtract the amount already delivered (

2\frac{1}{4}

) from the total required (

4\frac{3}{4}

). Subtracting the whole numbers gives

4 - 2 = 2

. Subtracting the fractions gives

\frac{3}{4} - \frac{1}{4} = \frac{2}{4}

, which simplifies to

\frac{1}{2}

. The remaining amount is

2\frac{1}{2}

pallets, which can be expressed as the decimal

2.5

.

Adım Adım Çözüm

1

Identify the total pallets required and the amount already delivered.

Total =

4\frac{3}{4}

pallets, Delivered =

2\frac{1}{4}

pallets.

Understanding the given values is necessary to determine the remaining balance.

2

Set up a subtraction equation to find the remaining pallets needed.

4\frac{3}{4} - 2\frac{1}{4}

Subtracting the part that has been delivered from the required total gives the remaining amount.

3

Subtract the whole numbers and the fractions.

4 - 2 = 2

and

\frac{3}{4} - \frac{1}{4} = \frac{2}{4}

.

Since the fractions already have a common denominator, they can be subtracted directly.

4

Simplify the fraction and convert to a decimal format.

\frac{2}{4}

simplifies to

\frac{1}{2}

. The mixed number

2\frac{1}{2}

equals

2.5

.

Numeric answers are typically expressed as decimals.

Anahtar Kavram

Subtracting mixed numbers with like denominators

Tahmini Süre:45s

Soru 3207Soru →

A neutral atom of sodium has an atomic number of $11$ and a mass number of $23$ . What is the total number of neutrons present in the nucleus of this atom?

11

12

23

34

Cevabı ve açıklamayı göster

Cevap: $12$

Cevap

12

neutrons

The mass number (

23

) is the total count of protons and neutrons in the nucleus, and the atomic number (

11

) is the number of protons. Subtracting the atomic number from the mass number (

23 - 11 = 12

) yields the exact number of neutrons.

Adım Adım Çözüm

1

Identify the number of protons and the total nucleon count from the given values.

Atomic number (

Z

) =

11

(protons), Mass number (

A

) =

23

(protons + neutrons)

The atomic number defines the number of protons, whereas the mass number represents the sum of protons and neutrons in the nucleus.

2

Calculate the number of neutrons by subtracting the atomic number from the mass number.

\text{Number of neutrons} = 23 - 11 = 12

Subtracting the proton count from the total mass number yields the quantity of neutrons.

Anahtar Kavram

The number of neutrons in an atom is calculated by subtracting the atomic number (number of protons) from the mass number (total protons and neutrons).

Tahmini Süre:35s

Soru 3208Soru →

Chemical compounds are commonly identified by both everyday names and standard IUPAC chemical formulas. Match each common chemical substance on the left with its correct chemical formula and characteristic reaction property on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Calcium carbonate matches with

CaCO_3

(carbonate salt releasing

CO_2

), Sodium hydroxide matches with

NaOH

(strong base used in drain cleaners), Hydrochloric acid matches with

HCl

(strong acid in gastric juices), and Methane matches with

CH_4

(combustible hydrocarbon producing

CO_2

and

H_2O

).

Each substance is accurately paired with its standard chemical formula and defining chemical reaction property: calcium carbonate (

CaCO_3

) produces carbon dioxide when acidified, sodium hydroxide (

NaOH

) acts as an alkaline cleaner, hydrochloric acid (

HCl

) serves as stomach acid and an industrial pickling agent, and methane (

CH_4

) combusts cleanly to produce carbon dioxide and water.

Adım Adım Çözüm

1

Identify the chemical identity and formula of limestone / calcium carbonate.

Limestone is composed of calcium (

Ca^{2+}

) and carbonate (

CO_3^{2-}

), giving the formula

CaCO_3

, which reacts with acids to form

CO_2

.

Matching common chemical names to their constituent ions and chemical behavior establishes the correct pair.

2

Identify the formula and basic nature of lye / sodium hydroxide.

Lye is sodium hydroxide (

NaOH

), a well-known strong base used in cleaning agents.

Recognizing alkali metals bonded to hydroxide ions identifies basic cleaning compounds.

3

Determine the composition and biological occurrence of muriatic acid.

Muriatic acid is an industrial name for hydrochloric acid (

HCl

), which is also secreted in the stomach to aid digestion.

Connecting mineral acid formulas to biological and commercial contexts confirms the match.

4

Classify natural gas / methane and its combustion behavior.

Methane is

CH_4

, an alkane hydrocarbon that combusts with

O_2

to generate carbon dioxide and water vapor.

Hydrocarbon oxidation is a fundamental reaction pattern in General Science.

Anahtar Kavram

Nomenclature, formulas, and fundamental chemical behaviors of common inorganic and organic compounds

Tahmini Süre:1m 0s

Soru 3209Soru →

A technician places a $500\text{ g}$ sample of liquid water into a sealed, airtight chamber and cools it until it freezes completely into solid ice. Which of the following statements correctly describes the changes in the sample's mass and volume?

The mass increases because solid ice is heavier than liquid water, while the volume remains constant.

The mass remains unchanged, but the volume decreases as the molecules pack closer together.

The mass remains unchanged, but the volume increases due to the expansion of water upon freezing.

The mass decreases because freezing triggers a chemical reaction that consumes matter, reducing the volume.

Cevabı ve açıklamayı göster

Cevap: The mass remains unchanged, but the volume increases due to the expansion of water upon freezing.

Cevap

The mass remains unchanged, but the volume increases due to the expansion of water upon freezing.

Freezing is a physical phase change that does not alter the chemical identity or quantity of matter in a closed system, so mass is strictly conserved at

500\text{ g}

. Unlike most liquids that contract upon solidifying, water uniquely expands upon freezing due to hydrogen bonding forming a spacious hexagonal crystal lattice, causing its volume to increase.

Adım Adım Çözüm

1

Evaluate the effect of freezing on the sample's mass in a sealed system.

The mass remains exactly

500\text{ g}

.

According to the Law of Conservation of Mass, the total quantity of matter in a closed system cannot change during a physical phase change.

2

Determine the effect of crystallization on the volume of water.

The volume of the water sample increases.

Water exhibits anomalous expansion upon freezing; hydrogen bonding locks water molecules into an open hexagonal lattice that takes up more space than the liquid phase.

3

Combine the mass and volume findings to identify the correct physical behavior.

Mass is conserved while volume increases (and density decreases).

Freezing is a physical process where mass stays constant while the physical arrangement of molecules increases the overall volume.

Anahtar Kavram

Conservation of mass during physical phase changes and the anomalous expansion of water upon freezing.

Tahmini Süre:1m 0s

Soru 3210Soru →

A customer buys a set of tires with an original total price of $\$600$ . The store offers a $20\%$ discount on the tires. After the discount is applied, a $5\%$ sales tax is added to the discounted price. What is the final total amount the customer pays?

\$126

\$510

\$504

\$609

Cevabı ve açıklamayı göster

Cevap: $\$504$

Cevap

The correct answer is

\$504

.

The correct final amount is found by first subtracting the discount from the original price, then adding the tax to the new subtotal. A

20\%

discount on

\$600

saves

\$120

, making the sale price

\$480

. A

5\%

tax on

\$480

adds

\$24

, resulting in a final total of

\$504

.

Adım Adım Çözüm

1

Calculate the amount of the discount.

The discount is

\$120

.

The discount is

20\%

of the original

\$600

price (

0.20 \times 600 = 120

).

2

Calculate the discounted sale price.

The sale price is

\$480

.

Subtract the discount amount from the original price (

600 - 120 = 480

).

3

Calculate the amount of the sales tax.

The sales tax is

\$24

.

The tax is

5\%

of the discounted sale price (

0.05 \times 480 = 24

).

4

Calculate the final total amount.

The final total is

\$504

.

Add the sales tax to the discounted sale price (

480 + 24 = 504

).

Anahtar Kavram

Calculating successive percentages involving discounts and taxes.

Soru 3211Soru →

In the study of classical mechanics, different physical quantities and forces describe how objects move and interact. Match each mechanical concept with its correct physical definition.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Displacement matches with the straight-line vector from starting to final position; Average speed matches with total path distance divided by elapsed time; Normal force matches with the perpendicular support force exerted by a surface; Unbalanced force matches with a non-zero net force causing a change in velocity.

Each concept correctly aligns with its precise definition in classical kinematics and dynamics: displacement measures the net position vector, average speed measures scalar distance over time, the normal force provides perpendicular support, and an unbalanced force produces net acceleration.

Adım Adım Çözüm

1

Identify the spatial vector measurement between two points.

Displacement represents the straight-line path and direction from initial to final position.

Unlike total distance, displacement depends only on the starting and ending positions.

2

Identify the scalar measure of motion rate.

Average speed equals total path distance divided by time elapsed.

Speed is scalar and does not take direction into account.

3

Identify the perpendicular contact force.

Normal force is the perpendicular push provided by a surface supporting a mass.

In physics, 'normal' means perpendicular to the contact plane.

4

Identify the cause of mechanical acceleration.

An unbalanced force produces a non-zero net force that accelerates an object.

Balanced forces maintain constant velocity (equilibrium), whereas unbalanced forces change motion.

Anahtar Kavram

Kinematic vector and scalar quantities alongside contact and net forces in mechanics

Tahmini Süre:1m 0s

Soru 3212Soru →

An uncharged atom of chlorine has $17$ electrons and $18$ neutrons in its structure. What is the mass number of this chlorine atom?

Cevabı ve açıklamayı göster

Cevap: 35

Cevap

The mass number of the chlorine atom is

35

.

For an uncharged atom, the number of protons equals the number of electrons (

17

). The mass number is the sum of protons and neutrons (

17 + 18 = 35

).

Adım Adım Çözüm

1

Determine the number of protons in the atom

17

protons

In any electrically neutral atom, the number of positively charged protons is equal to the number of negatively charged electrons.

2

Add the number of protons and neutrons together

17 + 18 = 35

The mass number (

A

) of an atom is defined as the total number of protons plus neutrons located in its nucleus.

Anahtar Kavram

The mass number of an atom is the sum of its protons and neutrons. In a neutral atom, the number of protons equals the number of electrons.

Tahmini Süre:45s

Soru 3213Soru →

When white light passes through a prism, it disperses into different colors of the visible spectrum. What is the correct order of the following colors of visible light when arranged from lowest wave frequency to highest wave frequency?

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence from lowest frequency to highest frequency is Red light, Yellow light, Green light, Violet light.

In the visible light spectrum, colors progress in order of decreasing wavelength and increasing frequency according to the sequence Red, Orange, Yellow, Green, Blue, Indigo, and Violet (ROYGBIV). Red light has the longest wavelength and lowest frequency, followed by yellow light, green light, and finally violet light, which has the shortest wavelength and highest frequency.

Adım Adım Çözüm

1

Recall the order of the visible light spectrum from longest wavelength to shortest wavelength.

The standard sequence of visible light colors is Red, Orange, Yellow, Green, Blue, Indigo, and Violet (ROYGBIV).

Visible light wavelengths decrease progressively from red light (~700 nm) to violet light (~400 nm).

2

Determine the relationship between wavelength and frequency using the wave speed equation

c = \lambda f

.

Frequency is inversely proportional to wavelength (

f = \frac{c}{\lambda}

).

Because electromagnetic waves travel at the speed of light in a vacuum, longer wavelengths correspond to lower frequencies and shorter wavelengths correspond to higher frequencies.

3

Sequence the given colors in order of increasing frequency.

Red light (lowest frequency) -> Yellow light -> Green light -> Violet light (highest frequency).

Following the ROYGBIV sequence, wave frequency increases continuously from red to violet.

Anahtar Kavram

Relationship between wavelength, frequency, and color sequence in the visible light spectrum

Tahmini Süre:45s

Soru 3214Soru →

Calculate the final sale price based on the given discount.

Aşağıdaki boşlukları doldurun

A mechanic buys a set of wrenches with a regular price of

\$80.00

. If he receives a

25\%

discount, the final price he pays is $\$$.

Cevabı ve açıklamayı göster

Cevap

60.00

To find the final price, first calculate

25\%

of the

\$80.00

regular price. Convert

25\%

to a decimal (

0.25

) and multiply by the regular price:

80 \times 0.25 = 20

. This means the discount is

\$20.00

. To find the final price paid, subtract this discount from the original price:

80 - 20 = 60

.

Adım Adım Çözüm

1

Calculate the dollar amount of the discount.

\$80.00 \times 0.25 = \$20.00

The discount is 25% of the regular price.

2

Subtract the discount amount from the regular price to find the final price.

\$80.00 - \$20.00 = \$60.00

The final price is the original price minus the calculated discount.

Anahtar Kavram

Calculating the final sale price by finding a percentage of the original cost and subtracting it.

Soru 3215Soru →

A technician working with lead-acid vehicle batteries observes several different processes in a maintenance facility. Which of the following processes represents a chemical reaction rather than a physical change?

Distilled water evaporating from an unsealed battery cell cap on a warm workbench

Solid lead terminal posts melting under high heat during terminal reshaping

Solid lead and lead dioxide reacting with sulfuric acid to produce lead sulfate during battery discharge

Water vapor in humid air condensing into liquid droplets on the cool exterior battery casing

Cevabı ve açıklamayı göster

Cevap: Solid lead and lead dioxide reacting with sulfuric acid to produce lead sulfate during battery discharge

Cevap

Solid lead and lead dioxide reacting with sulfuric acid to produce lead sulfate during battery discharge

The reaction between lead, lead dioxide, and sulfuric acid during battery discharge is a chemical change because the original substances are chemically altered to form an entirely new compound, lead sulfate (

PbSO_4

), releasing electrical energy through bond reorganization.

Adım Adım Çözüm

1

Differentiate between a chemical change and a physical change.

A chemical change involves the rearrangement of atoms via bond breaking and bond formation to yield new chemical substances with distinct properties. A physical change alters only physical form, shape, or state of matter while keeping the chemical composition unchanged.

Clear scientific criteria are required to evaluate the nature of each observed process.

2

Analyze the atomic and molecular changes occurring in each scenario.

Evaporating water (

H_2O_{(l)} \rightarrow H_2O_{(g)}

), melting lead (

Pb_{(s)} \rightarrow Pb_{(l)}

), and condensing water (

H_2O_{(g)} \rightarrow H_2O_{(l)}

) are all phase changes where molecular formulas remain identical. In contrast, lead-acid battery discharge involves lead (

Pb

), lead dioxide (

PbO_2

), and sulfuric acid (

H_2SO_4

) reacting to create a new chemical substance, lead sulfate (

PbSO_4

).

Determining whether chemical composition is conserved or transformed identifies the presence of a chemical reaction.

3

Identify the process that forms new chemical compounds.

The discharge of the lead-acid battery is the only process where reactants are converted into chemically distinct products.

The generation of lead sulfate (

PbSO_4

) confirms a chemical reaction.

Anahtar Kavram

Differentiating chemical reactions (which produce new substances with new chemical properties through bond breaking and formation) from physical phase changes (which preserve molecular composition).

Tahmini Süre:1m 0s

Soru 3216Soru →

Geologists use foundational stratigraphy rules to interpret the sequence of geological events recorded in rock strata. Match each relative dating principle with the statement that accurately defines its geological application.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Principle of Cross-Cutting Relationships matches the statement that cross-cutting features are younger than the rocks they penetrate; Principle of Original Horizontality matches the statement that sediments settle horizontally under gravity; Principle of Inclusions matches the statement that enclosed rock fragments are older than the host rock; Principle of Faunal Succession matches the statement that fossil assemblages occur in a predictable vertical sequence.

Each principle governs a distinct relative dating rule: Cross-Cutting Relationships determine that intrusive features or faults are younger than the rock layers they intersect; Original Horizontality dictates that sediments deposit in horizontal layers; Inclusions dictate that trapped fragments are older than the enclosing matrix; and Faunal Succession uses the non-repeating vertical order of fossils to correlate strata.

Adım Adım Çözüm

1

Identify the defining criteria for structural deformation and intrusion relative ages.

Cross-cutting features (faults/intrusions) are younger than the layers they cut, and flat deposition implies tilting happened after deposition.

Relative dating relies on geometric and physical interactions between rock bodies to establish chronological sequence.

2

Identify the defining criteria for internal rock inclusions and biological fossil sequences.

Xenoliths or clasts inside a host rock are older than the host, and biological taxa succeed each other predictably through time.

Inclusions must predate the matrix that surrounds them, while biological evolution provides an irreversible time index across global strata.

3

Pair each named geological principle to its exact operational definition.

All four principles are accurately matched to their respective stratigraphic definitions.

Ensures complete conceptual alignment without confusing relative age relationships.

Anahtar Kavram

Principles of Relative Dating and Stratigraphy

Tahmini Süre:1m 15s

Soru 3217Soru →

In a science laboratory, a technician analyzes a sample of phosphorus represented by the isotope symbol $^{31}_{15}\text{P}$ . What is the total number of neutrons contained in the nucleus of this phosphorus atom?

15

16

31

46

Cevabı ve açıklamayı göster

Cevap: $16$

Cevap

16

neutrons

In standard isotopic notation

^{A}_{Z}\text{X}

, the superscript (

A = 31

) is the mass number, representing the combined number of protons and neutrons, while the subscript (

Z = 15

) is the atomic number, representing the number of protons. The number of neutrons is found by subtracting the atomic number from the mass number (

31 - 15 = 16

).

Adım Adım Çözüm

1

Identify the mass number (

A

) and atomic number (

Z

) from the isotope notation

^{31}_{15}\text{P}

.

A = 31

and

Z = 15

.

In standard isotope notation, the upper superscript represents the mass number (

A

) and the lower subscript represents the atomic number (

Z

).

2

Calculate the number of neutrons using the relationship

\text{Neutrons} = A - Z

.

\text{Neutrons} = 31 - 15 = 16

.

The mass number equals the total number of protons and neutrons, while the atomic number equals the number of protons.

Anahtar Kavram

Calculating the number of neutrons in an atom using standard isotopic notation (

A - Z

).

Tahmini Süre:45s

Soru 3218Soru →

When a person shouts inside a large empty gymnasium, they hear their voice repeated a moment later as an echo. Which wave behavior is directly responsible for producing an echo?

Diffraction

Reflection

Refraction

Absorption

Cevabı ve açıklamayı göster

Cevap: Reflection

Cevap

Reflection is the wave behavior responsible for producing an echo.

An echo is heard when sound waves strike a rigid barrier and bounce back toward the listener. This bouncing back of a wave from a surface is defined as reflection.

Adım Adım Çözüm

1

Analyze the physical scenario of an echo

Sound waves travel outward from the source, strike a hard obstacle such as a gymnasium wall, and bounce back to the listener.

Identifying the motion of the wave as returning after hitting a boundary isolates the specific physical mechanism.

2

Associate the wave behavior with standard physical terminology

The bouncing back of waves upon encountering an impenetrable surface is defined as reflection.

An echo is a direct real-world example of sound wave reflection.

Anahtar Kavram

Sound wave reflection and echo formation

Tahmini Süre:45s

Soru 3219Soru →

An electronics store marks up the wholesale cost of a laptop by 40% to establish its regular retail price. During a clearance event, the laptop is discounted by 25% from its regular price. A customer then uses a special promotional code that takes an additional 10% off the sale price. If the final price the customer pays before tax is $756.00, what was the original wholesale cost of the laptop?

$623.70

$720.00

$800.00

$8,000.00

Cevabı ve açıklamayı göster

Cevap: $800.00

Cevap

The original wholesale cost of the laptop was $800.00.

The correct answer is found by representing the consecutive percent changes as multipliers (1.40 for a 40% markup, 0.75 for a 25% discount, and 0.90 for a 10% discount). Setting the product of these multipliers and the unknown wholesale cost equal to the final price (

W \times 1.40 \times 0.75 \times 0.90 = 756.00

) yields a net multiplier of 0.945. Dividing the final price of

756.00 by 0.945 gives the original wholesale cost of

800.00.

Adım Adım Çözüm

1

Let

W

be the wholesale cost. Represent the markup of 40% as a multiplier.

Regular price =

W \times 1.40

A 40% markup means the regular price is 140% of the wholesale cost.

2

Apply the 25% clearance discount to the regular price expression.

Sale price =

(W \times 1.40) \times 0.75 = W \times 1.05

A 25% discount means the customer pays 75% of the current price.

3

Apply the 10% promotional code discount to the sale price expression.

Final price =

(W \times 1.05) \times 0.90 = W \times 0.945

An additional 10% discount means the customer pays 90% of the sale price.

4

Set the final price expression equal to the given final price and solve for

W

.

W \times 0.945 = 756.00 \Rightarrow W = \frac{756.00}{0.945} = 800.00

This isolates

W

to find the original wholesale cost.

Anahtar Kavram

Calculating original value after successive percent changes (markups and discounts)

Soru 3220Soru →

Complete the following statement regarding the complete combustion of methane fuel by identifying the missing compound and the stoichiometric balancing coefficient.

Aşağıdaki boşlukları doldurun

During the complete combustion of methane (

CH_4

), the fuel reacts with atmospheric oxygen (

O_2

) to produce carbon dioxide (

CO_2

) and . In the balanced chemical equation

CH_4 + \underline{\quad} O_2 \rightarrow CO_2 + 2H_2O

, the numerical coefficient required in front of

O_2

is .

Cevabı ve açıklamayı göster

Cevap

The missing product compound is water (

H_2O

), and the balancing coefficient for oxygen gas (

O_2

) is 2.

In the complete combustion of any simple hydrocarbon such as methane (

CH_4

), the products are always carbon dioxide (

CO_2

) and water (

H_2O

). To balance the equation

CH_4 + x O_2 \rightarrow CO_2 + 2H_2O

, we tally the atoms on each side. Carbon has 1 atom on both sides; hydrogen has 4 atoms on both sides (

4

in

CH_4

and

2 \times 2 = 4

in

2H_2O

). The product side contains 4 total oxygen atoms (2 from

CO_2

and 2 from

2H_2O

). Therefore,

2

molecules of diatomic oxygen (

2 O_2

) are required on the reactant side to conserve mass.

Adım Adım Çözüm

1

Identify the missing chemical product containing hydrogen.

Water (

H_2O

)

Hydrocarbon combustion involves the oxidation of carbon to carbon dioxide (

CO_2

) and hydrogen to water (

H_2O

).

2

Count total oxygen atoms present in the products.

4 oxygen atoms total

The products consist of 1 molecule of

CO_2

(contributing 2 oxygen atoms) and 2 molecules of

H_2O

(contributing

2 \times 1 = 2

oxygen atoms), giving

2 + 2 = 4

oxygen atoms.

3

Determine the required coefficient for diatomic oxygen (

O_2

) on the reactant side to satisfy the law of conservation of mass.

A coefficient of 2

Since each

O_2

molecule contains 2 oxygen atoms, dividing 4 required oxygen atoms by 2 yields a stoichiometric coefficient of 2.

Anahtar Kavram

Hydrocarbon Combustion and Equation Balancing

Tahmini Süre:1m 0s

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