Calorimetry

Question 1

q(sys)

Answer 1

= - q(surr)

Question 2

q = mcΔT

Answer 2

Heat of a substance changing in temperature

Question 3

q = CΔT

Answer 3

Heat of an object changing in temperature

Question 4

ISOLATED SYSTEM???

Answer 4

This is a system that doesn’t allow the transfer of heat or mass to or from the surrounding.

Question 5

Constant Volume Calorimetry conditions…

Answer 5

1. ΔV is 0
   therefore W = -PΔV = 0
   therefore no work is done on the system.
   therefor ΔU = q

Question 6

A second identically sized ball, made from a metal with a higher specific heat capacity than
stainless steel, is subjected to the same conditions as part (a). Do you expect the mass of produced
steam to be greater or smaller? Explain.

Answer 6

If c is higher, then the amount of heat released by the ball is larger. Thus, the heat absorbed by
the water is greater. Since the amount of heat needed to raise the temperature of the water is
unchanged (q1 is the same), that means more heat is leftover to boil the water (q2 is larger).
Therefore, more steam will be produced.

Question 7

Is ΔH a state function or nah???

Answer 7

It is!!! ΔH is always the same no matter the path.

Question 8

Always remember these about ΔH(enthalpy)…

Answer 8

1. If the reaction is reversed ΔH is reversed
   2 H2O(l) → 2 H2(g) + O2(g)
   ΔH = +572 k

2 H2(g) + O2(g) → 2 H2O(l)
ΔH = -572 k

2.The magnitude of ΔH depends on the amount substance

2 H2O(l) → 2 H2(g) + O2(g)
ΔH = +572 k

4 H2O(l) → 4 H2(g) + 2 O2(g) ΔH = +1144 kJ

Question 9

ΔH(formation) is zero for the following…

Answer 9

1. Hydrogen
2. Nitrogen
3. Fluorine
4. Chlorine
5. Bromine
6. Iodine

Question 10

ΔH(reaction) =

Answer 10

ΔH(formation of products) - ΔH(formation of products)

AND

Sum of all the bonds broken - Sum of all the bonds formed

Question 11

ΔH(formation) is zero for the following…

Answer 11

1. Hydrogen
2. Nitrogen
3. Fluorine
4. Chlorine
5. Bromine
6. Iodine