Chapter 5 - Thermochemistry

Question 1

Specific heat of water

Answer 1

4.18 J/g K

Question 1

Density of water

Answer 1

1 g/mL

Question 2

Heat (q) =

Answer 2

the amount of energy transferred from one object to another because of a difference of temperature

Question 3

Enthalpy (H) =

Answer 3

the amount of energy transferred from one object to another because of a difference of temperature at a constant pressure!

Question 4

q = mC∆T

Answer 4

heat (Joules) = mass(g) x Specific Heat x Change in Temperature
Used when temperature is changing
q = -q when someone absorbs and other releases energy

Question 5

q = m∆H

Answer 5

heat (kilojoules) = mass(g) x ∆H(corresponding to the phase change ie evaporation, condensation, fusion, etc)
Used when changing state of matter

Question 6

Hess’s law

Answer 6

∆H is directly proportional to the number of moles, therefore if you increase or decrease the chemical reaction, the ∆H will also change by the same factor. You can also reverse the equation, which would also reverse the value of ∆H (make it negative)

Question 7

Standard Enthalpy of Formation

Answer 7

ΔH° = Σ(n × ΔHf°) (products) - Σ(n × ΔHf°) (reactants)
1 atm and 25 C