Exothermic reactions in solution give out energy and the temperature increases, while endothermic reactions take in energy and the temperature decreases. Bonds are broken and made in reactions.
What piece of apparatus could be used to find out if a chemical reaction was exothermic or endothemic?
What term is given to a reaction which transfers heat energy to the surroundings?
When barium hydroxide and ammonium chloride react, the temperature of the mixture decreases. What kind of reaction is this?
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 surrounding warmer
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
Which statement about energy changes during reactions is correct?
When energy is released to the surroundings the temperature falls
During an endothermic reaction energy is taken out of the surroundings
Combustion and neutralisation reactions can be exothermic or endothermic
What can you deduce from the reaction profile below?
The reaction is endothermic
A catalyst is present
More energy is given out than taken in
When calcium reacts with water, the temperature changes from 18°C to 39°C. Which statement is correct?
The reaction is exothermic
The reaction is reversible
If 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
= 130 kJ
150 + 110 = 260 kJ