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Flashcards in Thermochemistry Deck (42):
1

Unit for quantity of energy

Joules

2

The enthalpy change for a chemical reaction

Delta H reaction

3

The energy required to melt a solid at its melting point

The heat of fusion

4

Hess’ law

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

5

Exothermic reactions

He given to surroundings

6

Enthalpy

Heat

7

Final enthalpy value (products) is lower then starting so

It’s value of H is negative

8

Endothermic reactions

Absorbed from surroundings

9

Enthalpy of products is higher than starting so

The value of H is positive

10

Exothermic reactions are written on

The right

11

Endothermic reactions are written on

The left

12

Heat is written as a product when

Exothermic and reactant when endothermic

13

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

The number of moles of species involved

14

Quantity applies to

A balanced reaction as written

15

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

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

16

What is kinetic energy

Energy of motion

17

What is heat

Motion of

18

What is potential energy

Stored energy

19

What is potential energy stored in

Chemical bonds of compounds

20

Total energy is

Conserved

21

What is heat

Energy transferred

22

What is specific heat of a substance

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

23

Energy to freeze or condense

Vapor

24

Melting or boiling means

Being absorbed

25

Freezing or condensing

Energy is being released

26

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

Opposite

27

What phase changes are endothermic

Melting and evaporation

28

What the changes are exothermic

Freezing and condensation

29

In EXOTHERMIC

He given to surroundings

30

In ENDOTHERMIC

Heat absorbed from surroundings

31

What’s the difference between calories and joules

They are just two different measurements of the amounts of energy

32

What happens when energy is change from one form to another

All the energy can be accounted for

33

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

Heat capacity
Mass that absorbs heat
Temperature change

34

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

Greater than the energy stored in the bonds of the products

35

When doing an energy change by one mole

Just flip the signs

36

If the value of H is positive the reaction is

Endothermic

37

If the value of H is negative the reaction is

Exothermic

38

What factors are needed and that he capacity of an object

MCAT

39

Which substance has the highest specific heat capacity

Liquid water

40

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

Mix the reactants in a calorimeter and measure the temperature change

41

During a state change the temperature of a substance

Remains constant

42

What is Hess’ law of heat summation

It is used to calculate delta H for complicated chemical reactions