Physical Science Alıştırma Soruları — Armed Services Vocational Aptitude Battery (ASVAB) — Sayfa 4

Soru 61Soru →

A physicist conducts an experiment with a solid block on a perfectly frictionless horizontal track. On Earth, a constant horizontal force of $150\text{ N}$ applied to the block produces a forward acceleration of $3\text{ m/s}^2$ . If the physicist transports the exact same block and track to an exoplanet where the acceleration due to gravity is exactly one-fifth that of Earth, and applies the identical $150\text{ N}$ horizontal force, which of the following describes the block's resulting mass and forward acceleration?

The mass remains

50\text{ kg}

, and the acceleration remains

3\text{ m/s}^2

.

The mass decreases to

10\text{ kg}

, and the acceleration increases to

15\text{ m/s}^2

.

The mass remains

50\text{ kg}

, but the acceleration increases to

15\text{ m/s}^2

.

The mass decreases to

10\text{ kg}

, but the acceleration remains

3\text{ m/s}^2

.

Cevabı ve açıklamayı göster

Cevap: The mass remains $50\text{ kg}$ , and the acceleration remains $3\text{ m/s}^2$ .

Cevap

The mass remains

50\text{ kg}

, and the acceleration remains

3\text{ m/s}^2

.

The block's mass is an intrinsic property and remains

50\text{ kg}

regardless of the local gravitational field. Because the track is frictionless, the object's horizontal acceleration is determined solely by the applied horizontal force and its mass (

a = F/m

). Since neither the applied force (

150\text{ N}

) nor the mass (

50\text{ kg}

) changed, the acceleration remains exactly the same at

3\text{ m/s}^2

.

Adım Adım Çözüm

1

Calculate the mass of the block on Earth using Newton's second law (

F = ma

).

m = 150\text{ N} / 3\text{ m/s}^2 = 50\text{ kg}

.

Mass is the ratio of applied net force to the resulting acceleration.

2

Determine the mass of the block on the exoplanet.

The mass remains

50\text{ kg}

.

Mass is an intrinsic property of an object measuring its inertia; it does not change based on the local gravitational field.

3

Calculate the horizontal acceleration on the exoplanet.

a = F / m = 150\text{ N} / 50\text{ kg} = 3\text{ m/s}^2

.

On a frictionless horizontal surface, vertical forces (weight and normal force) do not impact horizontal motion. The only horizontal force is the

150\text{ N}

applied force, and because the mass is unchanged, the acceleration remains identical.

Anahtar Kavram

Invariance of Mass and Independence of Horizontal Inertia from Gravity

Soru 62Soru →

An automotive technician observes several processes taking place in a workshop. Which of the following processes is an example of a chemical change?

The evaporation of spilled degreaser on the concrete floor

The rusting of an iron vehicle frame exposed to moisture

The melting of solid solder wire using a heated soldering iron

The grinding of a steel brake rotor into fine metal shavings

Cevabı ve açıklamayı göster

Cevap: The rusting of an iron vehicle frame exposed to moisture

Cevap

The rusting of an iron vehicle frame exposed to moisture

The rusting of an iron frame represents a chemical reaction (oxidation) where metallic iron combines with oxygen and water to synthesize a new compound, iron oxide. Because a new chemical substance with unique properties is created, it is a chemical change.

Adım Adım Çözüm

1

Differentiate between physical and chemical changes.

A physical change alters form, state, or appearance without changing chemical identity. A chemical change produces one or more new chemical substances through the breaking and forming of bonds.

Establishing the core scientific definitions allows accurate classification of each workshop process.

2

Analyze the process involving the formation of rust on iron.

Iron (

Fe

) reacts with oxygen (

O_2

) and moisture (

H_2O

) to form hydrated iron(III) oxide (

Fe_2O_3 \cdot nH_2O

), which is a brand-new compound.

Since a new chemical compound with distinct properties is formed, the process is definitively a chemical change.

Anahtar Kavram

Chemical change involves a transformation where original substances combine or break down into new substances with different chemical properties.

Tahmini Süre:45s

Soru 63Soru →

A shop crane lifts a replacement motor vertically through a distance of $4\text{ meters}$ , performing $2{}000\text{ J}$ of work. What constant upward force is exerted by the crane?

8{}000\text{ N}

500\text{ N}

500\text{ kg}

500\text{ W}

Cevabı ve açıklamayı göster

Cevap: $500\text{ N}$

Cevap

The constant upward force exerted by the crane is

500\text{ N}

.

Work equals force multiplied by distance (

W = F \times d

). Dividing the total work of

2{}000\text{ J}

by the vertical distance of

4\text{ meters}

yields a constant force of

500\text{ N}

.

Adım Adım Çözüm

1

State the formula relating work, force, and distance.

W = F \times d

Work is defined as force applied over a parallel distance.

2

Rearrange the equation to solve for force.

F = \frac{W}{d}

Isolating force allows direct calculation from known work and distance values.

3

Substitute the given values (

W = 2{}000\text{ J}

and

d = 4\text{ m}

) into the rearranged formula.

F = \frac{2{}000\text{ J}}{4\text{ m}} = 500\text{ N}

Carrying out the division yields the magnitude of force in newtons.

Anahtar Kavram

Work and Force Relationship

Tahmini Süre:45s

Soru 64Soru →

Chemical transformations involve the rearrangement of atoms and bonds to create distinct substances. Match each described chemical reaction on the left with its corresponding balanced chemical equation on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Each reaction description matches its stoichiometrically balanced chemical equation representing the correct reaction archetype (decomposition, single displacement, neutralization, and combustion).

The correct pairings accurately connect standard chemical nomenclature and reaction archetypes (decomposition, single displacement, acid-base neutralization, and hydrocarbon combustion) to their fully balanced IUPAC stoichiometric equations.

Adım Adım Çözüm

1

Identify reactants, products, and reaction classification for each narrative prompt.

Decomposition produces simpler compounds from one reactant; displacement involves an elemental metal replacing an aqueous cation; neutralization pairs an acid and base to form salt and water; combustion combines a hydrocarbon/alcohol with oxygen to yield carbon dioxide and water.

Categorizing the reaction type narrows the corresponding structural formula patterns.

2

Verify chemical formulas and conservation of mass (balancing coefficients) for each equation.

Thermal decomposition corresponds to

\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2

; single displacement corresponds to

\text{Cu} + 2\text{AgNO}_3 \rightarrow \text{Cu}(\text{NO}_3)_2 + 2\text{Ag}

; neutralization corresponds to

\text{H}_2\text{SO}_4 + 2\text{NaOH} \rightarrow \text{Na}_2\text{SO}_4 + 2\text{H}_2\text{O}

; combustion corresponds to

\text{C}_2\text{H}_5\text{OH} + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 3\text{H}_2\text{O}

.

Every atom must balance across the reaction arrow in accordance with the Law of Conservation of Mass.

Anahtar Kavram

Classification and Stoichiometric Balancing of Chemical Reactions

Tahmini Süre:2m 0s

Soru 65Soru →

When a candle is lit, the heat from the flame causes the solid wax at the base of the wick to turn into liquid wax. Which of the following statements correctly describes this process?

It is a chemical change because heat breaks the wax molecules into completely new chemical substances.

It is a physical change because the wax changes its state of matter without altering its chemical composition.

It is a chemical change because the production of liquid from a solid indicates a chemical reaction occurred.

It is a physical change because the total mass of the wax decreases as it turns into a liquid.

Cevabı ve açıklamayı göster

Cevap: It is a physical change because the wax changes its state of matter without altering its chemical composition.

Cevap

The melting of solid wax is a physical change because the wax changes its state of matter without altering its chemical composition.

Melting is a phase change from solid to liquid, which is a classic physical change. During melting, the physical state and molecular arrangement change, but no new chemical substances are formed and the chemical formula of the wax remains unchanged.

Adım Adım Çözüm

1

Identify the process described in the scenario.

Solid wax changes into liquid wax due to heat, which is a phase change known as melting.

Determining the specific process allows classification as a physical or chemical event.

2

Analyze whether the chemical composition changes during melting.

The molecules of the wax remain identical before and after melting; only the distance and arrangement between particles change.

Physical changes involve changes in appearance or state without forming new chemical substances, whereas chemical changes produce new substances.

Anahtar Kavram

Physical versus chemical changes in matter

Tahmini Süre:45s

Soru 66Soru →

A remote-controlled toy boat with a mass of $2\text{ kg}$ accelerates across a calm pond at a rate of $3\text{ m/s}^2$ . What is the net horizontal force acting on the boat?

6\text{ kg}

6\text{ N}

1.5\text{ N}

6\text{ m/s}

Cevabı ve açıklamayı göster

Cevap: $6\text{ N}$

Cevap

The net horizontal force acting on the boat is

6\text{ N}

.

Newton's second law of motion states that net force equals mass multiplied by acceleration (

F = ma

). Multiplying the mass of

2\text{ kg}

by the acceleration of

3\text{ m/s}^2

yields a net force of

6\text{ N}

.

Adım Adım Çözüm

1

Identify the given values from the problem statement.

Mass

m = 2\text{ kg}

and acceleration

a = 3\text{ m/s}^2

.

Determining the known variables allows the direct application of Newton's second law of motion.

2

Apply the formula for Newton's second law of motion (

F = ma

).

F = 2\text{ kg} \times 3\text{ m/s}^2 = 6\text{ N}

.

Multiplying mass in kilograms by acceleration in meters per second squared yields force in newtons (

1\text{ N} = 1\text{ kg}\cdot\text{m/s}^2

).

Anahtar Kavram

Newton's Second Law of Motion (

F = ma

)

Tahmini Süre:45s

Soru 67Soru →

A science teacher simultaneously drops a steel hammer and a bird feather from the same height inside a sealed vacuum chamber that contains no air. Which of the following best predicts the motion of the two objects?

The hammer will hit the bottom first because an object with greater mass experiences a larger downward acceleration.

Both objects will hit the bottom at the exact same time because gravity accelerates all objects at the same rate in the absence of air resistance.

The feather will hit the bottom first because an object with less mass attains downward velocity more quickly in a vacuum.

The hammer will hit the bottom first because its weight measured in metric units causes it to reach terminal velocity sooner.

Cevabı ve açıklamayı göster

Cevap: Both objects will hit the bottom at the exact same time because gravity accelerates all objects at the same rate in the absence of air resistance.

Cevap

Both objects will hit the bottom at the exact same time because gravity accelerates all objects at the same rate in the absence of air resistance.

In the absence of air resistance, the only force acting on falling objects is gravity. Although a heavier object experiences a greater gravitational pull (weight), it also has proportionally greater inertia (resistance to acceleration). As a result of

a = \frac{F}{m} = g

, all objects accelerate downward at the constant rate of approximately

9.8\text{ m/s}^2

on Earth, reaching the surface at the exact same time when released together from the same height.

Adım Adım Çözüm

1

Identify the external forces acting on the objects inside the chamber.

Only the downward force of gravity acts on the objects, as air resistance is zero in a vacuum.

Recognizing the environmental conditions determines whether drag forces affect the fall.

2

Apply Newton's second law of motion (

F = ma

) to determine acceleration due to gravity.

The acceleration is calculated as

a = \frac{F_g}{m} = \frac{mg}{m} = g

.

Demonstrates that the mass

m

cancels out, proving acceleration is independent of mass.

3

Compare the arrival times of both falling objects released from the same height.

Since both start from rest with identical acceleration

g

, both take time

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

to reach the bottom.

Confirms that both items strike the floor simultaneously.

Anahtar Kavram

Acceleration due to gravity in free fall without air resistance

Tahmini Süre:45s

Soru 68Soru →

A $15\text{ kg}$ sled slides across a smooth ice rink at a constant velocity of $4\text{ m/s}$ . What is the magnitude of the sled's momentum in kilogram-meters per second ( $\text{kg}\cdot\text{m/s}$ )?

Cevabı ve açıklamayı göster

Cevap: 60

Cevap

60 kg·m/s

Linear momentum is calculated using the formula

p = m \times v

. For an object with a mass of

15\text{ kg}

moving at

4\text{ m/s}

, the momentum is

15\text{ kg} \times 4\text{ m/s} = 60\text{ kg}\cdot\text{m/s}

.

Adım Adım Çözüm

1

Identify the given mass and velocity values.

m = 15\text{ kg}

and

v = 4\text{ m/s}

Linear momentum depends directly on an object's mass and its velocity.

2

Apply the momentum formula

p = m \times v

.

p = 15\text{ kg} \times 4\text{ m/s} = 60\text{ kg}\cdot\text{m/s}

Multiplying mass by velocity calculates the magnitude of linear momentum.

Anahtar Kavram

Linear momentum is the product of an object's mass and its velocity (

p = mv

).

Tahmini Süre:45s

Soru 69Soru →

An astronaut takes a $100 \text{ g}$ solid block of a pure substance, which has an initial volume of $20 \text{ cm}^3$ , to a planet with twice the gravity of Earth. On the new planet, the block is heated until it completely melts, expanding to a volume of $25 \text{ cm}^3$ . Which of the following accurately describes the substance on the new planet compared to its initial state on Earth?

Its mass remains

100 \text{ g}

, its weight is doubled, and it undergoes a physical change that decreases its density to

4.0 \text{ g/cm}^3

.

Its mass and weight both double, and it undergoes a physical change that results in a density of

8.0 \text{ g/cm}^3

.

Its mass remains

100 \text{ g}

, its weight is doubled, and it undergoes a chemical change that decreases its density to

4.0 \text{ g/cm}^3

.

Its mass and weight both double, and it undergoes a chemical change that results in a density of

8.0 \text{ g/cm}^3

.

Cevabı ve açıklamayı göster

Cevap: Its mass remains $100 \text{ g}$ , its weight is doubled, and it undergoes a physical change that decreases its density to $4.0 \text{ g/cm}^3$ .

Cevap

The correct answer is that its mass remains 100 g, its weight is doubled, and it undergoes a physical change that decreases its density to 4.0 g/cm³.

The mass of an object is constant regardless of the gravitational environment, so it remains

100 \text{ g}

. Weight is a force dependent on gravity (

W = mg

), so placing the object in an environment with twice the gravity doubles its weight. Melting is a phase change, which is strictly a physical change, not a chemical one. Finally, density is mass divided by volume (

D = m/V

); since the mass is

100 \text{ g}

and the new volume is

25 \text{ cm}^3

, the resulting density is

4.0 \text{ g/cm}^3

.

Adım Adım Çözüm

1

Determine the effect of increased gravity on mass and weight.

Mass remains

100 \text{ g}

, while weight doubles.

Mass is an intrinsic measure of the amount of matter and is independent of gravity, whereas weight is the gravitational force acting on that mass (

W = mg

).

2

Identify the type of change occurring during the melting process.

Melting is classified as a physical change.

A phase change from solid to liquid alters the state and volume of a substance but does not change its fundamental chemical composition.

3

Calculate the final density of the liquid on the new planet.

Density

= 4.0 \text{ g/cm}^3

.

Density is calculated as mass divided by volume. Using the constant mass (

100 \text{ g}

) and the new volume (

25 \text{ cm}^3

), the new density is

100 \text{ g} / 25 \text{ cm}^3 = 4.0 \text{ g/cm}^3

.

Anahtar Kavram

Distinguishing between mass and weight, classifying phase changes, and calculating density.

Tahmini Süre:2m 0s

Soru 70Soru →

A rectangular glass container with internal base dimensions of $5\text{ cm}$ by $4\text{ cm}$ contains water. A solid mineral specimen with a mass of $130\text{ g}$ is completely submerged into the water, causing the water level to rise by $2.5\text{ cm}$ without spilling. What is the density of the mineral specimen in $\text{g/cm}^3$ ?

Cevabı ve açıklamayı göster

Cevap: 2.6

Cevap

The density of the mineral specimen is

2.6\text{ g/cm}^3

.

Density is calculated by dividing mass by volume (

\rho = \frac{m}{V}

). The water displacement method reveals the object's volume:

\text{Volume} = \text{length} \times \text{width} \times \Delta h = 5\text{ cm} \times 4\text{ cm} \times 2.5\text{ cm} = 50\text{ cm}^3

. Dividing the given mass of

130\text{ g}

by the displaced volume of

50\text{ cm}^3

yields exactly

2.6\text{ g/cm}^3

.

Adım Adım Çözüm

1

Calculate the volume of the displaced water inside the rectangular container.

V = 5\text{ cm} \times 4\text{ cm} \times 2.5\text{ cm} = 50\text{ cm}^3

The volume of fluid pushed upward corresponds to the area of the base multiplied by the change in water height.

2

Equate the volume of the submerged solid to the displaced fluid volume.

V_{\text{specimen}} = 50\text{ cm}^3

By the principle of fluid displacement, a completely submerged solid displaces a volume of fluid exactly equal to its own physical volume.

3

Calculate the density of the specimen using the mass-to-volume ratio.

\rho = \frac{m}{V} = \frac{130\text{ g}}{50\text{ cm}^3} = 2.6\text{ g/cm}^3

Density is an intensive physical property defined as mass per unit volume.

Anahtar Kavram

Density is an intensive physical property of matter defined as mass per unit volume (

\rho = m/V

), determinable for irregular or submerged solids via fluid displacement.

Tahmini Süre:1m 30s

Soru 71Soru →

In mechanical systems, energy is transferred and transformed through various types of forces and work. Match each mechanical operation with its primary energy transformation or work process.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Compressing a suspension spring matches with conversion of mechanical work into elastic potential energy; applying friction brake pads matches with conversion of kinetic energy into thermal energy via frictional work; lifting an engine block vertically matches with conversion of mechanical work into gravitational potential energy; spinning up a flywheel from rest matches with conversion of mechanical work into rotational kinetic energy.

Each mechanical operation corresponds directly to a fundamental energy transition: deforming a spring stores elastic potential energy, friction converts moving kinetic energy into dissipated thermal energy, elevating a mass increases gravitational potential energy, and accelerating a rotating mass stores kinetic energy.

Adım Adım Çözüm

1

Analyze the suspension spring compression

Work is done against spring tension, resulting in stored elastic potential energy.

Deforming an elastic medium stores mechanical energy internally.

2

Analyze the friction braking process

Kinetic energy of motion is converted directly into heat through friction.

Friction opposes motion over a distance, converting mechanical energy into thermal energy.

3

Analyze the vertical lifting hoist

Work done against Earth's gravitational pull increases gravitational potential energy (

PE = mgh

).

Increasing height at constant speed transfers work directly into gravitational potential energy.

4

Analyze the accelerating flywheel

Work applied as torque increases the angular velocity and rotational kinetic energy (

KE = \frac{1}{2}I\omega^2

).

Accelerating mass into motion represents an accumulation of kinetic energy.

Anahtar Kavram

Work-Energy Theorem and Forms of Energy Transformation

Tahmini Süre:1m 0s

Soru 72Soru →

In physical science, chemical reactions are categorized by how reactant atoms and compounds interact to form products. Match each described chemical reaction scenario on the left with its correct reaction classification on the right.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Burning propane in oxygen matches Combustion; Splitting water into hydrogen and oxygen matches Decomposition; Combining magnesium and oxygen into magnesium oxide matches Synthesis; Mixing hydrochloric acid and sodium hydroxide matches Neutralization.

Each process demonstrates a core category of chemical change: burning propane with oxygen to produce carbon dioxide and water is combustion; splitting water into hydrogen and oxygen gas via electricity is decomposition; combining magnesium and oxygen into a single compound is synthesis; and mixing hydrochloric acid with sodium hydroxide to create salt and water is neutralization.

Adım Adım Çözüm

1

Identify the reaction where a fuel rapidly reacts with oxygen gas (

O_2

) producing energy, carbon dioxide (

CO_2

), and water (

H_2O

).

Burning propane corresponds to a Combustion reaction (

C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O

).

Combustion occurs when a substance combines with oxygen rapidly, releasing heat and light.

2

Identify the process where a single reactant compound breaks down into two or more distinct products.

Splitting water into hydrogen and oxygen corresponds to a Decomposition reaction (

2H_2O \rightarrow 2H_2 + O_2

).

Decomposition represents the breakdown of a single substance into simpler parts.

3

Identify the process where two or more individual reactants join together to create a single compound.

Combining magnesium and oxygen into magnesium oxide corresponds to a Synthesis reaction (

2Mg + O_2 \rightarrow 2MgO

).

Synthesis involves building up a larger or more complex molecule from simpler elements or compounds.

4

Identify the reaction where an acidic solution and a basic solution react to yield a neutral salt and water.

Mixing hydrochloric acid and sodium hydroxide corresponds to a Neutralization reaction (

HCl + NaOH \rightarrow NaCl + H_2O

).

Neutralization is an acid-base double displacement reaction where hydrogen and hydroxide ions combine to form water.

Anahtar Kavram

Classifying Fundamental Chemical Reactions

Tahmini Süre:45s

Soru 73Soru →

In residential heating, propane gas ( $\text{C}_3\text{H}_8$ ) burns in the presence of oxygen ( $\text{O}_2$ ) to form carbon dioxide ( $\text{CO}_2$ ) and water vapor ( $\text{H}_2\text{O}$ ) according to the unbalanced chemical equation:

\text{C}_3\text{H}_8 + \underline{\hspace{0.8cm}}\,\text{O}_2 \rightarrow 3\text{CO}_2 + 4\text{H}_2\text{O}

What coefficient must be placed before $\text{O}_2$ to completely balance this equation using the lowest whole numbers?

10

5

7

3

Cevabı ve açıklamayı göster

Cevap: 5

Cevap

5

The coefficient 5 is correct because the product side contains a total of 10 oxygen atoms (6 from

3\text{CO}_2

and 4 from

4\text{H}_2\text{O}

). Since molecular oxygen is diatomic (

\text{O}_2

), 5 molecules of

\text{O}_2

(

5 \times 2 = 10

atoms) are required to balance the reaction.

Adım Adım Çözüm

1

Count the total number of oxygen atoms on the product side of the equation.

The products contain

(3 \times 2) + (4 \times 1) = 6 + 4 = 10

oxygen atoms.

By the Law of Conservation of Mass, the number of oxygen atoms in the reactants must equal the number in the products.

2

Determine the coefficient needed for diatomic oxygen gas (

\text{O}_2

) on the reactant side.

10 \div 2 = 5

Because each

\text{O}_2

molecule contains 2 oxygen atoms, 5 molecules are required to provide the 10 needed atoms.

Anahtar Kavram

Balancing chemical equations by conserving atoms across reactants and products

Tahmini Süre:1m 0s

Soru 74Soru →

In a submarine life-support system, carbon dioxide ( $CO_2$ ) is scrubbed from the cabin atmosphere by reacting with solid lithium hydroxide ( $LiOH$ ) to produce solid lithium carbonate ( $Li_2CO_3$ ) and water vapor ( $H_2O$ ). Which of the following represents the correctly balanced chemical equation for this reaction?

LiOH + CO_2 \rightarrow Li_2CO_3 + H_2O

2LiOH + CO_2 \rightarrow Li_2CO_3 + H_2O

Li_2OH + CO_2 \rightarrow Li_2CO_3 + H_2O

LiOH + CO_2 \rightarrow LiCO_2 + H_2O

Cevabı ve açıklamayı göster

Cevap: $2LiOH + CO_2 \rightarrow Li_2CO_3 + H_2O$

Cevap

The balanced chemical equation is

2LiOH + CO_2 \rightarrow Li_2CO_3 + H_2O

.

Placing a coefficient of 2 in front of lithium hydroxide yields equal quantities of each element on both sides: 2 lithium atoms, 1 carbon atom, 4 oxygen atoms, and 2 hydrogen atoms, satisfying the law of conservation of mass.

Adım Adım Çözüm

1

Write the unbalanced skeleton equation using the correct chemical formulas for all reactants and products.

LiOH + CO_2 \rightarrow Li_2CO_3 + H_2O

Establishing the correct formulas ensures that the identities of the chemical substances are maintained.

2

Count the number of each type of atom on both sides of the equation.

Reactants: 1 Li, 1 C, 3 O, 1 H. Products: 2 Li, 1 C, 4 O, 2 H.

An atom inventory reveals which elements violate the law of conservation of mass.

3

Place a coefficient of 2 in front of

LiOH

on the reactant side to balance the lithium and hydrogen atoms.

2LiOH + CO_2 \rightarrow Li_2CO_3 + H_2O

Using whole-number coefficients balances atoms without altering compound identities.

4

Re-verify the atom count for every element across the entire equation.

Reactants: 2 Li, 1 C, 4 O, 2 H. Products: 2 Li, 1 C, 4 O, 2 H.

Confirming equal atom counts ensures the equation satisfies the law of conservation of mass.

Anahtar Kavram

Balancing chemical equations by adding stoichiometric coefficients while keeping chemical formulas unchanged.

Tahmini Süre:1m 30s

Soru 75Soru →

A pneumatic test probe is launched vertically upward from ground level with an initial kinetic energy of $450\text{ J}$ . Assuming air resistance is negligible, what is the kinetic energy of the probe at the point where it has gained $300\text{ J}$ of gravitational potential energy?

300\text{ J}

150\text{ J}

750\text{ J}

0\text{ J}

Cevabı ve açıklamayı göster

Cevap: $150\text{ J}$

Cevap

150\text{ J}

In the absence of air resistance, the total mechanical energy of the system remains constant (

E = KE + PE = 450\text{ J}

). When the probe gains

300\text{ J}

of gravitational potential energy, the remaining kinetic energy is

450\text{ J} - 300\text{ J} = 150\text{ J}

.

Adım Adım Çözüm

1

Determine the total initial mechanical energy of the probe at launch.

Total Mechanical Energy (

E

) =

450\text{ J}

At ground level before rising, all mechanical energy is kinetic energy (

KE = 450\text{ J}

,

PE = 0\text{ J}

).

2

Apply the law of conservation of mechanical energy.

E = KE + PE = 450\text{ J}

In the absence of air resistance, the total mechanical energy of the system remains constant throughout the upward climb.

3

Calculate the remaining kinetic energy at the given potential energy level.

KE = 450\text{ J} - 300\text{ J} = 150\text{ J}

Subtract the gained gravitational potential energy from the total conserved mechanical energy.

Anahtar Kavram

Conservation of Mechanical Energy

Tahmini Süre:1m 0s

Soru 76Soru →

A sealed, rigid $250\text{ mL}$ container holds $50\text{ g}$ of solid carbon dioxide (dry ice) at sea level on Earth. The container is transported to a research outpost on Mars, where surface gravity is approximately $38\%$ of Earth's gravity. During transport, the dry ice completely sublimates into carbon dioxide gas at room temperature inside the sealed container. Which statement correctly evaluates the physical and chemical properties of the carbon dioxide upon arrival at Mars?

Sublimation is a chemical change that forms a new gas compound, reducing the total mass of the sealed system while its weight remains constant.

Sublimation is a physical change that conserves the

50\text{ g}

mass of carbon dioxide, while the weight of the substance decreases due to lower Martian gravity.

Sublimation is a physical change, but the mass of the carbon dioxide decreases to

38\%

of its Earth value because of the reduced gravitational field.

Sublimation is a chemical change where intramolecular bonds break into individual elements, causing both the mass and weight of the carbon dioxide to decrease.

Cevabı ve açıklamayı göster

Cevap: Sublimation is a physical change that conserves the $50\text{ g}$ mass of carbon dioxide, while the weight of the substance decreases due to lower Martian gravity.

Cevap

Sublimation is a physical change that conserves the

50\text{ g}

mass of carbon dioxide, while the weight of the substance decreases due to lower Martian gravity.

The correct answer accurately states that sublimation (transition from solid directly to gas) is a physical change preserving the chemical identity of

CO_2

. Because the container is sealed, the mass remains invariant at

50\text{ g}

. However, because Martian gravity is only

38\%

of Earth's gravity, the weight (

W = mg

) decreases accordingly.

Adım Adım Çözüm

1

Classify the phase change process (sublimation).

Sublimation is a physical change, not a chemical change.

Converting solid carbon dioxide to gaseous carbon dioxide changes only the physical state and arrangement of molecules, not their chemical composition.

2

Determine the mass of the substance in the sealed container on Mars.

Mass remains exactly

50\text{ g}

.

According to the Law of Conservation of Mass, matter is neither created nor destroyed in a closed system, and mass is an intrinsic property independent of gravity.

3

Analyze the effect of Martian gravity on the weight of the substance.

Weight decreases to approximately

38\%

of its Earth value.

Weight is the gravitational force exerted on an object (

W = mg

), which is directly proportional to the local gravitational field strength.

Anahtar Kavram

Distinction between physical vs. chemical changes and mass vs. weight across varying gravitational environments

Tahmini Süre:1m 30s

Soru 77Soru →

An electric winch applies a constant horizontal pulling force of $220\text{ N}$ to drag a heavy storage crate across a level concrete floor for a distance of $15\text{ meters}$ in $6\text{ seconds}$ . What is the average power output delivered by the winch in watts?

Cevabı ve açıklamayı göster

Cevap: 550

Cevap

The average power output of the winch is

550\text{ W}

.

Work equals force multiplied by distance (

220\text{ N} \times 15\text{ m} = 3300\text{ J}

). Power is the rate of work done per second (

3300\text{ J} / 6\text{ s} = 550\text{ W}

).

Adım Adım Çözüm

1

Calculate the work done by multiplying force by distance

W = 220\text{ N} \times 15\text{ m} = 3300\text{ J}

Work measures the energy transferred by a force acting over a displacement in the direction of the force (

W = Fd

).

2

Calculate the power output by dividing work done by elapsed time

P = \frac{3300\text{ J}}{6\text{ s}} = 550\text{ W}

Power represents the rate at which work is done over time (

P = \frac{W}{t}

).

Anahtar Kavram

Work is calculated as the product of force and displacement (

W = Fd

), and power is the rate of doing work over time (

P = \frac{W}{t}

).

Tahmini Süre:1m 0s

Soru 78Soru →

Fill in the missing stoichiometric coefficient and chemical formula in the neutralization equation below. What coefficient and compound formula correctly complete the reaction?

Aşağıdaki boşlukları doldurun

When sulfuric acid (

\text{H}_2\text{SO}_4

) reacts with sodium bicarbonate (

\text{NaHCO}_3

), the complete neutralization reaction is represented by:

\text{H}_2\text{SO}_4 +

\text{NaHCO}_3 \rightarrow

+ 2\text{H}_2\text{O} + 2\text{CO}_2

.

Cevabı ve açıklamayı göster

Cevap

The missing coefficient is 2 and the missing chemical formula is Na2SO4.

A coefficient of 2 is necessary for sodium bicarbonate (NaHCO3) to provide the 2 carbon atoms and 2 sodium atoms found in the products (2CO2 and Na2SO4). The resulting salt is sodium sulfate, whose empirical formula is Na2SO4 because two +1 sodium cations (Na+) are needed to balance one -2 sulfate polyatomic anion (SO4^2-).

Adım Adım Çözüm

1

Balance the carbon and hydrogen atoms between reactants and products to find the coefficient for sodium bicarbonate.

The coefficient for NaHCO3 is 2.

The product side contains 2 carbon atoms (in 2CO2) and a total of 4 hydrogen atoms (in 2H2O), requiring 2 moles of NaHCO3 to combine with 1 mole of H2SO4 on the reactant side.

2

Determine the chemical formula of the salt produced by pairing sodium cations with sulfate anions.

The chemical formula of the salt is Na2SO4.

Sodium forms a singly charged cation (Na+) while the sulfate polyatomic ion carries a -2 charge (SO4^2-), meaning two sodium ions are required to balance one sulfate ion electrically.

3

Verify the conservation of each atomic species across the complete chemical equation.

Reactants: 4 H, 1 S, 10 O, 2 Na, 2 C. Products: 4 H, 1 S, 10 O, 2 Na, 2 C.

The Law of Conservation of Mass requires that the number of atoms of each element on the reactant side must equal the number on the product side.

Anahtar Kavram

Stoichiometric equation balancing and compound formula determination in acid-carbonate neutralization reactions.

Tahmini Süre:1m 30s

Soru 79Soru →

A researcher conducts two separate experiments in a laboratory.

In Experiment 1, a chunk of solid carbon dioxide is submerged in room-temperature water, producing vigorous bubbling.
In Experiment 2, a piece of solid calcium metal is submerged in room-temperature water, which also produces vigorous bubbling, along with a noticeable increase in temperature and the formation of a cloudy white suspension.

Based on the evidence provided, which of the following best classifies the two experiments and correctly identifies the primary gas generating the bubbles in the experiment that represents a chemical change?

Experiment 1 is a physical change and Experiment 2 is a chemical change; the gas released in Experiment 2 is hydrogen (

H_2

).

Both experiments represent chemical changes; the gas released in Experiment 1 is carbon dioxide (

CO_2

) and the gas released in Experiment 2 is oxygen (

O_2

).

Experiment 1 is a physical change and Experiment 2 is a chemical change; the gas released in Experiment 2 is oxygen (

O_2

).

Experiment 1 is a chemical change and Experiment 2 is a physical change; the gas released in Experiment 1 is carbon dioxide (

CO_2

).

Cevabı ve açıklamayı göster

Cevap: Experiment 1 is a physical change and Experiment 2 is a chemical change; the gas released in Experiment 2 is hydrogen ( $H_2$ ).

Cevap

Experiment 1 is a physical change and Experiment 2 is a chemical change; the gas released in Experiment 2 is hydrogen (

H_2

).

The correct answer accurately identifies that solid carbon dioxide sublimating into carbon dioxide gas is a physical change because the chemical structure does not change. It also accurately recognizes that calcium reacting with water is a chemical change that produces a new solid compound (calcium hydroxide) and hydrogen gas (

H_2

).

Adım Adım Çözüm

1

Analyze Experiment 1 for signs of chemical vs. physical change.

Solid carbon dioxide (dry ice) in water undergoes sublimation (solid to gas).

Bubbling occurs as carbon dioxide transitions phases. No new substance is formed, meaning this is a physical change.

2

Analyze Experiment 2 for signs of chemical vs. physical change.

Calcium in water produces heat (exothermic), a precipitate (cloudy suspension), and gas bubbles.

The combination of heat generation and the formation of new distinct substances indicates a chemical change.

3

Determine the products of the chemical reaction in Experiment 2.

The reaction is

Ca + 2H_2O \rightarrow Ca(OH)_2 + H_2

.

Alkaline earth metals react with water in a single replacement reaction to form a metal hydroxide and hydrogen gas, not oxygen gas.

Anahtar Kavram

Distinguishing physical phase changes from chemical reactions and predicting products of metal-water reactions.

Tahmini Süre:1m 30s

Soru 80Soru →

During an outdoor camping trip, several activities take place around the campsite. Which of the following activities is an example of a chemical change?

Melting ice cubes inside an insulated cooler

Burning dry firewood in a campfire

Boiling river water in a metal pot

Crushing aluminum beverage cans for recycling

Cevabı ve açıklamayı göster

Cevap: Burning dry firewood in a campfire

Cevap

Burning dry firewood in a campfire

Burning dry firewood is a combustion reaction where organic compounds in wood chemically react with oxygen gas to yield new chemical products, including carbon dioxide, water vapor, and ash, accompanied by the release of heat and light.

Adım Adım Çözüm

1

Analyze each activity to determine whether new chemical substances are formed or only the physical state/shape changes.

Melting ice, boiling water, and crushing cans alter physical state or form without creating new molecules; burning wood reacts with oxygen to form new substances (ash,

\text{CO}_2

, and

\text{H}_2\text{O}

).

A chemical change is defined by the rearrangement of atoms to form one or more new chemical substances.

2

Select the activity that involves a chemical reaction.

Combustion of firewood is identified as the chemical change.

Combustion is an irreversible chemical reaction that releases energy and produces distinct products.

Anahtar Kavram

Chemical change versus physical change

Tahmini Süre:40s

Physical Science

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