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Question 1

: What is the principle of conservation of mass?

Answer 1

: Conservation of mass states that during a change of state, the number of molecules and thus the mass of a substance remain constant

Question 2

What happens to internal energy during a change of state?

Answer 2

: Internal energy changes during a change of state. It increases with an increase in temperature,

Question 3

What are the six changes of state that can occur between solids, liquids, and gases?

Answer 3

Back:
Melting: When a solid turns into a liquid (e.g., ice to water).
Evaporating: When a liquid turns into a gas.
Condensing: When a gas turns into a liquid.
Freezing: When a liquid turns into a solid.
Subliming: When a solid turns directly into a gas.

Question 4

What are physical changes?

Answer 4

changes that do not alter the chemical composition of a substance. reversible, and the material recovers its original properties if the change is reversed.

Question 5

How do physical changes differ from chemical changes?

Answer 5

Back: Physical changes are reversible, while chemical changes are not. Chemical changes involve a transformation of one substance into another with different chemical properties.

Question 6

Front: Describe the arrangement of molecules in solids, liquids, and gases.
Back:

Answer 6

In a solid, molecules are very close together and arranged in a regular pattern, vibrating about fixed positions.
In a liquid, molecules are close together but not in a regular pattern, allowing them to slide past each other.
In a gas, molecules are widely separated and move about randomly at high speeds

Question 7

: What are the two forms of energy possessed by molecules within a substance?

Answer 7

Back: The molecules within a substance possess kinetic energy due to their random motion/vibration, and potential energy due to their position relative to each other.

Question 8

Define internal energy.

Answer 8

Back: Internal energy is the total energy stored inside a system by the particles that make up the system due to their motion and positions.

Question 9

How is internal energy related to kinetic and potential energy?

Answer 9

Back: Internal energy is the sum of kinetic energy and potential energy of the particles within a system.

Question 10

Front: How does heating a system affect a substance’s internal energy?

Answer 10

Back: Heating a system increases a substance’s internal energy by increasing the kinetic energy of its particles.

Question 11

Front: How is temperature related to the average kinetic energy of molecules?

Answer 11

Back: The temperature of a material is related to the average kinetic energy of its molecules. Higher temperature corresponds to higher kinetic energy, and vice versa.

Question 12

What effect does an increase in kinetic energy have on molecules?

Answer 12

Back: An increase in kinetic energy causes molecules to move around faster, leading to higher internal energy.

Question 13

t: How can an increase in internal energy caused by heating affect the system?

Answer 13

Back: An increase in internal energy caused by heating can:
Cause the temperature of the system to increase.
Produce a change of state, such as solid to liquid or liquid to gas.

Question 14

What happens when a substance reaches a certain temperature during heating?

Answer 14

Back: When a substance reaches a certain temperature, the kinetic energy of the molecules stops increasing, and the energy goes into increasing its potential energy instead.

Question 15

How does an increase in potential energy affect the molecules during a change of state?

Answer 15

Back: An increase in potential energy breaks the bonds between the molecules, causing them to move further apart, which leads to a change of state, such as liquid to gas.

Question 16

Describe what happens to the potential energy and kinetic energy of molecules during a change of state.

Answer 16

Back: During a change of state, the potential energy of the molecules increases as bonds between them break and they move further apart, while the kinetic energy remains the same. This means that the temperature will remain constant, even though the substance is still being heated.

Question 17

Front: What does a heating curve show?

Answer 17

Back: shows how the temperature of a substance changes with time as it is heated

Question 18

What happens to the substance at each section of the heating curve?

Answer 18

Back: At each section of the heating curve, heat energy is used to either increase the kinetic energy of the particles, break the bonds between molecules, or both, resulting in changes of state from solid to liquid to gas.

Question 19

What is specific heat capacity?

Answer 19

the amount of energy required to raise the temperature of 1 kg of a substance by 1°C.

Question 20

How does the specific heat capacity of a substance affect its heating and cooling behavior?

Answer 20

Substances with low specific heat capacities, heat up and cool down quickly because it takes less energy to change their temperature.
Substances with high specific heat capacities, heat up and cool down slowly because it takes more energy to change their temperature.

Question 21

Front: What is specific latent heat?

Answer 21

amount of thermal energy required to change the state of 1 kg of a substance with no change in temperature

Question 22

What are the two types of specific latent heat?
Back: The two types of specific latent heat are:

Answer 22

Specific latent heat of fusion: The thermal energy required to convert 1 kg of solid to liquid with no change in temperature.

Specific latent heat of vaporisation: The thermal energy required to convert 1 kg of liquid to gas with no change in temperature.

Question 23

How do specific heat capacity and specific latent heat differ?

Answer 23

Back: Specific heat capacity is used for changes in temperature within the same state of matter, while specific latent heat is used for changes in state without a change in temperature.

Question 24

What does specific heat capacity describe?

Answer 24

Back: Specific heat capacity describes the energy required to raise the temperature of a substance. It specifically refers to raising the temperature of 1 kg of a substance by 1 degree Celsius.

Question 25

Front: What is the equation to calculate the change in thermal energy?

Answer 25

Back: The equation to calculate the change in thermal energy is:
ΔQ = mcΔθ
Where ΔQ is the change in thermal energy (in joules), m is the mass (in kilograms), c is the specific heat capacity (in joules per kilogram per degree Celsius), and Δθ is the change in temperature (in degrees Celsius).