Energy changes in chemical reactions test questions - WJEC

1

What term is given to a reaction which transfers heat energy to the surroundings?

2

What temperature change takes place in an endothermic reaction?

3

Which of the following processes is endothermic?

4

What is the effect of a reaction if the energy involved in breaking bonds is less than the energy involved in forming bonds?

5

If the energy change on an energy level diagram is negative, what does this tell you about the reaction?

6

On a reaction profile, what does the height of the hump represent?

7

What is the definition of activation energy?

8

The bond energy of the H–H bond is 436 kJ. Which of these statements is true?

9

The energy changes during a reaction are as follows.

Energy to break bonds = 150 kJ

Energy to form bonds = 110 kJ

Which of the following is the correct calculation of the overall energy change?

10

What is the energy change for the reaction H–H + F–F → 2H–F?

Bond energies: H–H = 436 kJ, F–F = 158 kJ, H–F = 565 kJ