AnswersSY2026-27 - 2003340 Chemistry 1 Sem 2 CRLab: Boyle’s Law

Heat Answers

10 verified answers
1
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Two samples of carbon come into contact. A heat transfer will occur between sample A and sample B. What must be true for heat to transfer from sample A to sample B?

A
The average kinetic energy of A is greater than that of B.
B
The average kinetic energy of B is greater than that of A.
C
The average kinetic energy of both samples is equal.
D
The average kinetic energy does not determine the direction of heat transfer.
2
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The diagram below shows the temperature dropping from 80°C to 20°C.Molecules that have longer arrows are moving faster. Which statement describes what is happening in this system?

Question illustration
A
Molecules vibrate more as temperature decreases.
B
Temperature is not related to the average kinetic energy of a system.
C
Kinetic energy decreases as temperature decreases.
D
There is no change in average kinetic energy between these two systems.
3

The temperature of a sample of liquid water changes from 50°C to 30°C. Which statement best explains the change that must happen at the molecular level?

A
The molecules move more quickly and their average kinetic energy increases.
B
The molecules move more slowly and their average kinetic energy decreases.
C
The molecules move more quickly and their average kinetic energy decreases.
D
The molecules move more slowly and their average kinetic energy increases.
4

Which event is endothermic?

A
the burning of a match
B
the change of water vapor to a liquid
C
the combustion of propane gas
D
the melting of ice
5

The temperature of a gas is increased. Which statement best explains the effect that this has on the motion of gas particles?

A
The average kinetic energy decreases, and the particles stop colliding.
B
The average kinetic energy increases, and the particles stop colliding.
C
The average kinetic energy decreases, and the particles collide less frequently.
D
The average kinetic energy increases, and the particles collide more frequently.
6

Two different gases are stored in separate closed containers. If both gases have a temperature of 50°C, which statement is true?

A
The thermal energies of gas molecules in the two containers are unrelated.
B
The gas molecules in both containers will absorb heat from the surroundings.
C
The molecules in one gas will transfer energy to the molecules in the other gas.
D
The gas molecules in both containers have the same average kinetic energy.
7

A student touches a freshly baked cake that was taken out of the oven. Which best explains why the cake feels hot?

A
Molecules in the skin are moving faster than molecules in the cake.
B
Molecules in the cake are moving faster than molecules in the skin.
C
The kinetic energy of molecules in the cake is more than the energy in the baking tray.
D
The kinetic energy of molecules in the baking tray is more than the energy in the cake.
8

In what type of reaction or process does heat flow into the system?

A
combustion
B
exothermic
C
condensation
D
endothermic
9

A baker touches a pie right after taking it out of the oven. Which statement best explains why the pie feels hot?

A
Molecules in the skin move faster than molecules in the pie, so heat is transferred to the pie.
B
Molecules in the pie move faster than molecules in the skin, so heat is transferred to the skin.
C
Molecules in the skin move faster than molecules in the pie, so heat is transferred to the skin.
D
Molecules in the pie move faster than molecules in the skin, so heat is transferred to the pie.
10

Which answer defines exothermic reaction?

A
a process in which energy is released as heat
B
a process in which energy is absorbed as heat
C
a process in which energy is stored and released
D
a process in which energy is not present in a system
11

What is thermal energy?

A
the average overall volume of a system
B
the total number of molecules in a system
C
the kinetic energy of particles in a system
D
the measure of temperature in a system
12

Which statement about exothermic reactions is accurate?

A
As reactants form products, the potential energy decreases.
B
As reactants form products, the potential energy increases.
C
Thermal energy is transferred from the product to the reacting substances.
D
Thermal energy is transferred from the surroundings to the reacting substances.
13

An ice cube is placed on a kitchen counter. Which best describes heat flow in this situation?

A
Heat flows from the ice to the counter, causing the molecules in the counter to move more quickly.
B
Heat flows from the ice to the counter, causing the molecules in the counter to move more slowly.
C
Heat flows from the counter to the ice, causing the molecules in the counter to move more quickly.
D
Heat flows from the counter to the ice, causing the molecules in the counter to move more slowly.
14

Heat that flows by conduction is the transfer of thermal energy between substances in contact. What must occur for this to happen?

A
The two systems must be the same temperature.
B
The two systems must not be touching each another.
C
One system must have higher kinetic energy than the other system.
D
The thermal energy of one system must be the same as the thermal energy of the other system.
15

Which reaction is exothermic?

A
CH4 + 2O2 CO2 + 2H2O + 891 kJ
Option A
B
NH4NO3 + H2O + 25 kJ NH4+(aq) + NO3-(aq)
Option B
C
2H2O + 286 kJ 2H2 + O2
Option C
D
N2 + O2 + 181 kJ 2NO
Option D

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