Reaction profiles

Question 1

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

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

Question 2

Reactants: 140 kJ. Peak of the profile: 190 kJ. Products: 175 kJ. What is the activation energy, in kJ?

Answer kJ

Question 3

On a reaction profile, the reactants are at 80 kJ, the peak is at 120 kJ and the products are at 60 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ

Question 4

How does a catalyst change a reaction profile?

• A. It lowers the peak (activation energy) but not the overall energy change
• B. It changes an exothermic reaction into an endothermic one
• C. It removes the reactants
• D. It raises the products

Question 5

Reactants: 140 kJ. Peak of the profile: 225 kJ. Products: 110 kJ. What is the activation energy, in kJ?

Answer kJ

Question 6

On a reaction profile, the reactants are at 100 kJ, the peak is at 160 kJ and the products are at 10 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ

Question 7

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

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

Question 8

Reactants: 110 kJ. Peak of the profile: 180 kJ. Products: 145 kJ. What is the activation energy, in kJ?

Answer kJ

Question 9

On a reaction profile, the reactants are at 200 kJ, the peak is at 300 kJ and the products are at 110 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ

Question 10

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

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

Question 11

Reactants: 90 kJ. Peak of the profile: 190 kJ. Products: 110 kJ. What is the activation energy, in kJ?

Answer kJ

Question 12

On a reaction profile, the reactants are at 120 kJ, the peak is at 270 kJ and the products are at 150 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ

Question 13

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

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

Question 14

Reactants: 90 kJ. Peak of the profile: 160 kJ. Products: 40 kJ. What is the activation energy, in kJ?

Answer kJ

Question 15

On a reaction profile, the reactants are at 200 kJ, the peak is at 300 kJ and the products are at 240 kJ. What is the overall energy change, in kJ? (Use a minus sign if energy is released.)

Answer kJ

Question 16

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. The spark provides the activation energy
• D. Methane is endothermic