Thermochemistry

Question 1

Unit for quantity of energy

Answer 1

Joules

Question 2

The enthalpy change for a chemical reaction

Answer 2

Delta H reaction

Question 3

The energy required to melt a solid at its melting point

Answer 3

The heat of fusion

Question 4

Hess’ law

Answer 4

If you add two or more Thermal chemical equations to give a final equation you can also add the heat of reaction to give the final heat of reaction

Question 5

Exothermic reactions

Answer 5

He given to surroundings

Question 6

Enthalpy

Answer 6

Heat

Question 7

Final enthalpy value (products) is lower then starting so

Answer 7

It’s value of H is negative

Question 8

Endothermic reactions

Answer 8

Absorbed from surroundings

Question 9

Enthalpy of products is higher than starting so

Answer 9

The value of H is positive

Question 10

Exothermic reactions are written on

Answer 10

The right

Question 11

Endothermic reactions are written on

Answer 11

The left

Question 12

Heat is written as a product when

Answer 12

Exothermic and reactant when endothermic

Question 13

The amount of heat released or absorbed during a reaction depends on

Answer 13

The number of moles of species involved

Question 14

Quantity applies to

Answer 14

A balanced reaction as written

Question 15

How is thermal energy transferred between two objects that are different temperatures

Answer 15

He always flows from higher to lower temperatures until they reach the same temperature

Question 16

What is kinetic energy

Answer 16

Energy of motion

Question 17

What is heat

Answer 17

Motion of

Question 18

What is potential energy

Answer 18

Stored energy

Question 19

What is potential energy stored in

Answer 19

Chemical bonds of compounds

Question 20

Total energy is

Answer 20

Conserved

Question 21

What is heat

Answer 21

Energy transferred

Question 22

What is specific heat of a substance

Answer 22

Heat needed to raise the temperature of 1 g of a substance by 1°C

Question 23

Energy to freeze or condense

Answer 23

Vapor

Question 24

Melting or boiling means

Answer 24

Being absorbed

Question 25

Freezing or condensing

Answer 25

Energy is being released

Question 26

If a reaction is reversed, the H for the reaction must be

Answer 26

Opposite

Question 27

What phase changes are endothermic

Answer 27

Melting and evaporation

Question 28

What the changes are exothermic

Answer 28

Freezing and condensation

Question 29

In EXOTHERMIC

Answer 29

He given to surroundings

Question 30

In ENDOTHERMIC

Answer 30

Heat absorbed from surroundings

Question 31

What’s the difference between calories and joules

Answer 31

They are just two different measurements of the amounts of energy

Question 32

What happens when energy is change from one form to another

Answer 32

All the energy can be accounted for

Question 33

What factors do you need to know in order to calculate the heat change in a calorimeter

Answer 33

Heat capacity
Mass that absorbs heat
Temperature change

Question 34

Describe the energy of a chemical bonds of the reactance an exothermic reactions

Answer 34

Greater than the energy stored in the bonds of the products

Question 35

When doing an energy change by one mole

Answer 35

Just flip the signs

Question 36

If the value of H is positive the reaction is

Answer 36

Endothermic

Question 37

If the value of H is negative the reaction is

Answer 37

Exothermic

Question 38

What factors are needed and that he capacity of an object

Answer 38

MCAT

Question 39

Which substance has the highest specific heat capacity

Answer 39

Liquid water

Question 40

How can you determine the enthalpy for a reaction in an aqueous solution

Answer 40

Mix the reactants in a calorimeter and measure the temperature change

Question 41

During a state change the temperature of a substance

Answer 41

Remains constant

Question 42

What is Hess’ law of heat summation

Answer 42

It is used to calculate delta H for complicated chemical reactions