In general, what happens to the temperature during an exothermic reaction?
It increases
It stays the same
It decreases
Which of these is an example of an endothermic reaction?
Combustion
Acid-alkali neutralisation
Thermal decomposition
Which of these statements is correct?
Energy is taken in to break bonds and when bonds form
Energy is taken in to break bonds and given out when bonds form
Energy is taken in when bonds form and given out when bonds are made
What happens in an exothermic reaction?
More energy is given out than is taken in from the surroundings
Energy is given out but no energy is taken in from the surroundings
Less energy is given out than is taken in from the surroundings
What is the most suitable apparatus to determine if a reaction in solution is exothermic or endothermic?
Joulemeter
Thermometer
Newtonmeter
In a reaction profile, if the products have more energy than the reactants, what does this tell you?
It is a combustion reaction
It is an exothermic reaction
It is an endothermic reaction
Which of the following is a correct statement about bond breaking?
It is exothermic
It releases energy
It is endothermic
What term is given to the energy needed for a reaction to occur?
Energy change
Activation energy
Bond energy
The bond energy for the O=O bond is 498 kJ/mol. How much energy is needed to break 0.5 mol of O=O bonds?
0.5 × 498 = 249 kJ
0.5 × 2 × 498 = 498 kJ
0.5 ÷ 2 × 498 = 124.5 kJ
What is the energy change for this reaction? H-H + I-I → 2 × (H-I) Bond energies in kJ/mol: H-H = 436, I-I = 151, H-I = 298.
+9 kJ/mol
-9 kJ/mol
289 kJ/mol