1. EXPERIMENT

2. RESULTS
TIME (SECONDS)
TEMPERATURE (OC) 20 5 35 10 55 15 50
MAXIMUM TEMPERATURE
Question 1 - Calculate the energy released in your reaction. The density of water is 1 g/cm3 . The specific heat capacity of water is 4.2 J/g/°C.
ANSWER
DH = mcDT
= 25 X 4.2 X (55 – 20) = 3675J = 3.675kJ

3. ANSWER The Zinc was in excess
QUESTION 2 - Calculate the moles of zinc that you used.
ANSWER
REMEMBER From C2 (Additional Science)
MOLES = MASS ÷ Mr
∴ MOLES = 2 ÷ 65 = mols of Zinc
QUESTION 3 - The moles of CuSO4 solution that was used was mols. Which substance Zn or CuSO4 was in excess?
ANSWER
The Zinc was in excess

4. ANSWER For Zinc = 3.675 ÷ 0.0308 = 119kJ/mol
QUESTION 4 - Calculate the energy change in kJ/mol for the chemicals reacting
ANSWER
For Zinc = ÷ = 119kJ/mol
For CuSO4 = ÷ = 294kJ/mol

5. a) Calculate the energy released in this reaction in kJ
QUESTION -5g of zinc was added to 75cm3 of 1moldm-3 solution of CuSO4 solution. The temperature rose from 25 to 670C.
a) Calculate the energy released in this reaction in kJ
b) Calculate the moles of Zinc metals used
c) The moles of CuSO4 used in this experiment was 0.075mols. Which substance Zinc or CuSO4 was in excess?
d) Calculate the energy change in kJ/mol for the chemicals reacting
ANSWER
DH = mcDT
= 75 x 4.2 x (67 – 25) =
= 13230J = 13.23kJ
b) Moles = Mass ÷ Mr = 5/65 = mols Zinc
c)The zinc was in excess
d) For Zinc = ÷ 65 = 0.204kJ/mol
For CuSO4 = ÷ = 176.4kJ/mol

6. REMEMBER
METAL HYDROXIDE + ACID  SALT + WATER
This is a neutralisation reaction

7. Question 1- Calculate the energy released in your reaction
Question 1- Calculate the energy released in your reaction. The density of water is 1 g/cm3 . The specific heat capacity of water is 4.2 J/g/°C.
ANSWER
DH = m x c x DT
= 50 x 4.2 x 28
= 5880J = 5.88kJ
Question 2 -The number of moles of the acid used was 0.025mols. Calculate the energy released in the reaction in kJ/mol
ANSWER
5.88/0.025 = 235kJ/mol

8. The energy released in the reaction in kJ
QUESTION - 75cm3 of 0.5moldm-3 HCl reacts with 75cm3 of 0.5moldm-3 NaOH. The temperature rose from 20 to 420C.
Calculate:
The energy released in the reaction in kJ
The moles of HCl used in this reaction is mols. Calculate the energy released in the reaction in kJ/mol
ANSWERS
13.86kJ
369.6kJ/mol

9. A BOMB CALORIMETER