Reaction profiles

Question 1

On a reaction profile, the reactants are at 150 kJ, the peak is at 190 kJ and the products are at 120 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ

Question 2

Reactants: 110 kJ. Peak of the profile: 195 kJ. Products: 145 kJ. What is the activation energy, in kJ?

Answer kJ

Question 3

Why does a mixture of methane and air not burn until a spark is added?

• A. The spark removes carbon dioxide
• B. The spark provides the activation energy
• C. The spark adds oxygen
• D. Methane is endothermic

Question 4

On a reaction profile, the reactants are at 200 kJ, the peak is at 395 kJ and the products are at 275 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ

Question 5

Reactants: 60 kJ. Peak of the profile: 110 kJ. Products: 80 kJ. What is the activation energy, in kJ?

Answer kJ

Question 6

Self-heating cans for camping use a reaction between calcium oxide and water. What type of reaction is this?

• A. exothermic
• B. endothermic
• C. electrolysis
• D. thermal decomposition

Question 7

On a reaction profile, the reactants are at 80 kJ, the peak is at 180 kJ and the products are at 50 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ

Question 8

Reactants: 110 kJ. Peak of the profile: 235 kJ. Products: 80 kJ. What is the activation energy, in kJ?

Answer kJ

Question 9

Why does a mixture of methane and air not burn until a spark is added?

• A. The spark adds oxygen
• B. The spark removes carbon dioxide
• C. Methane is endothermic
• D. The spark provides the activation energy

Question 10

On a reaction profile, the reactants are at 80 kJ, the peak is at 160 kJ and the products are at 120 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ

Question 11

Reactants: 140 kJ. Peak of the profile: 290 kJ. Products: 90 kJ. What is the activation energy, in kJ?

Answer kJ

Question 12

Self-heating cans for camping use a reaction between calcium oxide and water. What type of reaction is this?

• A. electrolysis
• B. thermal decomposition
• C. exothermic
• D. endothermic

Question 13

On a reaction profile, the reactants are at 80 kJ, the peak is at 240 kJ and the products are at 120 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ

Question 14

Reactants: 140 kJ. Peak of the profile: 290 kJ. Products: 160 kJ. What is the activation energy, in kJ?

Answer kJ

Question 15

On a profile, the products are higher than the reactants. What kind of reaction is it?

• A. exothermic
• B. combustion
• C. endothermic
• D. neutralisation

Question 16

On a reaction profile, the reactants are at 120 kJ, the peak is at 260 kJ and the products are at 180 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ