Which of the following is the correct definition for a catalyst?
A substance that increases the rate of a chemical reaction without being used up.
A substance that increases the rate of a chemical reaction but is used up.
A substance that decreases the rate of a chemical reaction without being used up.
Increasing the concentration of a reactant increases the rate of reaction because:
It gives the particles more energy.
It increases the number of collisions per unit time.
It lowers the activation energy barrier.
Which of the following will cause a change in the activation energy?
Increasing the temperature.
Adding a catalyst.
Using larger solid particles.
Which set of reaction conditions will produce the fastest reaction between sulfuric acid and calcium carbonate?
Powdered calcium carbonate and 2 mol/dm3 sulfuric acid at 30oC.
Lumps of calcium carbonate and 2 mol/dm3 sulfuric acid at 30oC.
Powdered calcium carbonate and 2 mol/dm3 sulfuric acid at 20oC.
The rate of the reaction between calcium carbonate and hydrochloric acid cannot be studied by:
Recording the volume of carbon dioxide gas produced over a period of time.
Recording the change in mass of the reaction mixture over a period of time.
Recording the mass of solid precipitate formed over a period of time.
Which of the following is the correct explanation for why increasing the temperature of a reaction increases the rate of reaction?
The particles gain energy and there are more successful collisions per second.
The particles lose energy and there fewer successful collision per second.
The particles gain energy and there are fewer successful collisions per second.
The rate of a reaction is determined by which of the following?
time
\[ \frac {1}{time}\]
\[ \frac {1}{(time)^2}\]
Which is the correct definition for the activation energy?
It is the minimum energy change in a reaction.
It is the minimum energy required for a reaction not to occur.
It is the minimum energy required for a reaction to occur.
Which of the following statements is true?
Increasing the particle size does not change the surface area to volume ratio.
Decreasing the particle size decreases the surface area to volume ratio.
Decreasing the particle size increases the surface area to volume ratio.
A catalyst provides:
An alternative reaction pathway of higher activation energy.
An alternative reaction pathway of lower activation energy.
An alternative reaction pathway with no change in activation energy.