Chapter 17.1

Question 0

Define heat

How does it flow and what is used to measure it

Answer 0

Sum total of the KE of all particles in a sample of matter

Flows from [high] to [low]

Question 1

Define thermochemistry and give another name for it

Answer 1

The study of heat changes that accompany chemical rxns and physical changes
Thermodynamics

Question 2

Describe a calorimeter and how it works

Answer 2

Contains h2o in an insulated vessel
Rxn occurs in a known mass of h2o
Heat absorbed or released by h2o = that absorbed or released by rxn
Data is t showing heT changes

Question 3

Describe temperature and it’s units

Answer 3

Measures the average KE of particles in a sample of matter
Unit in joules which is the metric unit of heat or NRG
1J=kg m2/sec2

Question 4

Define specific heat symbol and unit

Answer 4

Amount if heT NRG required to raise t of a substance by 1 c or K
Symbol is Cp
Units joules /g c

Question 5

What has the highest specific heat and give an example

Answer 5

H2o

4.18 j/g c

Question 6

Define heat capacity what are the three things it depends on

Answer 6

The ability of a material to absorb heat

1. Material changing of T
2. The mass
3. Size if the change in t

Question 7

Specific heat equation and variables

Answer 7

Cp= q/(m)change of T
Cp= specific heat 
Q heat ab/re. J
M mass g
T. K

Question 8

What’s another name for heat of rxn and define it

Answer 8

Enthalpy
The amount if heat absorbed or released in a chemical rxn or the difference in heat btw the stored NRG if the reactants and that if the products

Question 9

What are the two possible values for enthalpy

Answer 9

Exothermic -heat released; feels hot
Change in H is beget ice as heat is lost
Reactants have a higher heat content than products

Endothermic - heat absorbed feels cold
Change in H is positive as heat is gained
Products have higher heat content

Question 10

How do you calc enthalpy

Answer 10

ChangeH= Hproducts - Hreactants

Question 11

When ChangeH is a high negative value…

Answer 11

Stable compound is forming spontaneously, vigorously
Large amounts of NRG released as products form
This is most common b/c reactants gain stability

Question 12

When ChangeH is positive or low negative

Answer 12

Unstable compound may form and may decompose violently

Question 13

Define heat of combustion

Answer 13

Heat released by the complete combustion of 1 mol of a substance