What term is given to a reaction which transfers heat energy to the surroundings?
Endothermic
Reversible
Exothermic
What temperature change takes place in an endothermic reaction?
The temperature of the surroundings decreases
The temperature of the surroundings increases
The temperature of the surroundings stays the same
Which of the following processes is endothermic?
Bonds being broken in the reactants
Bonds being made in the products
Any combustion reaction
What is the effect of a reaction if the energy involved in breaking bonds is less than the energy involved in forming bonds?
The reaction doesn't change the temperature of the surroundings
The reaction makes the surroundings colder
The reaction makes the surroundings warmer
If the energy change on an energy level diagram is negative, what does this tell you about the reaction?
It is endothermic
Nothing
It is exothermic
On a reaction profile, what does the height of the hump represent?
The activation energy
The energy change
The energy released when new bonds are made
What is the definition of activation energy?
The energy needed to break all the bonds in the reactants
The energy needed to make a reaction start
The energy produced as the reaction takes place
The bond energy of the H–H bond is 436 kJ. Which of these statements is true?
It takes 436 kJ to break a H–H bond
It takes 436 kJ to break one mole of H–H bonds
It takes 436 kJ to break 436 H–H bonds
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?
150 – 110 = 40 kJ
\(\frac{150 + 110}{2}\) = 130 kJ
150 + 110 = 260 kJ
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
+536 kJ
+29 kJ
–536 kJ