Thermodynamics Energy Basics Chapter 5.1

Question 1

Thermochemistry

Answer 1

area of science concerned with the amount of heat absorbed or released during chemical and physical changes

Question 2

Energy

Answer 2

capacity to supply heat or do work

Question 3

potential energy

Answer 3

the energy an object has because of its relative position, composition, or condition

Question 4

Kinectic energy

Answer 4

the energy that an object possesses because of its motion

Question 5

The law of conservation of energy:

Answer 5

during a chemical or physical change, energy can be neither created nor destroyed, although it can be changed in form

Question 6

The law of conservation of matter

Answer 6

During any physical or chemical change, the total mass of the products remains equal to the total mass of the reactants.

Question 7

Thermal energy

Answer 7

kinetic energy associated with the random motion of atoms and molecules

Question 8

Temperature

Answer 8

Hotness or coldness of an object

Question 9

When the atoms and molecules in an object are moving or
vibrating quickly, they have a …. and we say that the object is ___

Answer 9

higher average kinetic energy (KE),

hot

Question 10

When the atoms and molecules are moving slowly, they have …, and we say that the object is “___”

Answer 10

lower average KE

cold

Question 11

Assuming that no chemical reaction or phase change (such as melting or vaporizing) occurs, increasing/decreasing the amount of thermal energy in a sample of matter …..

Answer 11

will cause its temperature to increase. And, assuming that no chemical reaction or phase change (such as condensation or freezing) occurs, decreasing the amount of thermal energy in a sample of matter will cause its temperature to decrease.

Question 12

Heat

Answer 12

The transfer of thermal energy between two bodies at different temperatures

Question 13

What does Heat flow do

+when does it stop?

Answer 13

Increases the thermal energy of one body and decreases the thermal energy of the other. Heat flow will continue until the two substances are at the same temperature

Question 14

Exothermic process

Answer 14

A chemical reaction that RELEASES heat (has a negative ΔH).

Question 15

Endothermic process

Answer 15

A reaction or change that absorbs heat

Question 16

Thermal equilibrium (3)

Answer 16

Both substances are at the
- same temp
- their molecules have same average kinectic energy.

No net flow of thermal energy between them when they are connected by a path permeable to heat.

Question 17

Calories+why its not used as a unit for energy (3)

Answer 17

The amount of energy required to raise one gram of water by 1 degree C (1 kelvin).

However, this quantity depends on the atmospheric pressure and the starting temperature of the water.

Question 18

The SI unit of heat, work, and energy

Answer 18

Joule

Question 19

Joule

Answer 19

the amount of energy used when a force of 1 newton moves an object 1 meter.

Question 20

heat capacity (C)

Answer 20

the quantity of heat (q) it absorbs or releases when it experiences a temperature change (ΔT) of 1 degree Celsius (or equivalently, 1 kelvin):

Question 21

heat capacity (C)
(3)

+formula+ trait+what it is

Answer 21

the quantity of heat (q) it absorbs or releases when it experiences a temperature change (ΔT) of 1 degree Celsius (or equivalently, 1 kelvin)

extensive property

Question 22

What is heat capacty determined by?

Answer 22

Heat capacity is determined by both the type and amount of substance that absorbs or releases heat.

Question 23

extensive property

Answer 23

its value is proportional to the amount of the substance.

Question 24

Why is heat capacity dependent on mass? (2)

Use pan as the compared example +what’s the relationship with mass and HC?

Answer 24

More mass means more atoms are present in the larger pan, so it takes more energy to make all of those atoms vibrate faster.

The larger pan has a (proportionally) larger heat capacity because the larger amount of material requires a (proportionally) larger amount of energy to yield the same temperature change

Question 25

heat capacity and mass relationship

Answer 25

They are directly porportional

Question 26

The specific heat capacity (c)

(4)

+formula+what it depends on+the property vocab

Answer 26

• the quantity of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius (or 1 kelvin)
• depends only on the kind of substance absorbing or releasing heat
• intensive property

Question 27

Intensive property

Answer 27

a physical quantity whose value does not depend on the amount of substance which was measured.

ex: specific heat capacity. The mass doesnt change the SPH value

Question 28

Specific heat capacity is derived from

hint: 2 extensive properties

Answer 28

being derived from a ratio of two extensive properties (heat and mass).

Heat is an extensive property, and is proportional to the total energy of all atoms in an object.

Question 29

specific heat capacity/ heat capacity value of large and small pan example exaplanation:

*same diff?

Answer 29

Because of its larger mass, a large frying pan has a larger heat capacity than a small frying pan. Because they are made of the same material, both frying pans have the same specific heat.

Question 30

Enthalpy change is the heat change when

Answer 30

Enthalpy change equals Heat change at constant pressure.