Rates Of Rections

Question 0

What factors affect the rate of a reaction?

Answer 0

The temperature, concentration, pressure of reacting gases, surface area of reacting solids, and the use of catalysts.

Question 1

How can a rate of a reaction be measured ?

Answer 1

The rate of a reaction can be measured by the rate at which a reactant is used up, or the rate at which a product is formed.

Question 2

How do chemical reactions happen?

Answer 2

Chemical reactions can only happen if reactant particles collide with enough energy.

Question 3

The more frequently particles collide, and the greater the……

Answer 3

proportion of collisions with enough energy, the greater the rate of reaction.

Question 4

Different reactions can happen at different rates. Reactions that happen slowly have a low rate of reaction. Reactions that happen quickly have a high rate of reaction.Name an example for both reactions.

Answer 4

For example, the chemical weathering of rocks is a very slow reaction: it has a low rate of reaction. Explosions are very fast reactions: they have a high rate of reaction.

Question 5

What is a reactant?

Answer 5

Substances present at the start of a chemical reaction

Question 6

What is a product of a reaction?

Answer 6

A product is a substance formed in a chemical reaction.

Question 7

What do you measure during a reaction?

Answer 7

The mass of a substance and the volume of the mass.

Question 8

It is usual to record the mass or total volume at regular intervals and plot a graph. What label goes on each axis?

Answer 8

Y axis: Readings

X axis: Time

Question 9

What is the equation for the rate of a reaction ?

Answer 9

Time taken

Question 10

How do you increase the rate of a reaction?

Answer 10

The temperature is increased
The concentration of a dissolved reactant is increased
The pressure of a reacting gas is increased
Solid reactants are broken into smaller pieces
A catalyst is used

Question 11

For a chemical reaction to occur, the…

Answer 11

reactant particles must collide. Collisions with too little energy do not produce a reaction.

Question 12

What is the collision theory?

Answer 12

The collision must have enough energy for the particles to react. The minimum energy needed for particles to react is called the activation energy.

Question 13

If the concentration of a dissolved reactant is increased, or the pressure of a reacting gas is increased…

Answer 13

There are more reactant particles in the same volume
There is a greater chance of the particles colliding
The rate of reaction increases

Question 14

If a solid reactant is broken into small pieces or ground into a powder…

Answer 14

Its surface area is increased
More particles are exposed to the other reactant
There is a greater chance of the particles colliding
The rate of reaction increases

Question 15

If the temperature is increased…

Answer 15

The reactant particles move more quickly
More particles have the activation energy or greater
The particles collide more often, and more of the collisions result in a reaction
The rate of reaction increases

Question 16

Using a catalyst in a reaction…

Answer 16

Catalysts increase the rate of reaction without being used up. They do this by lowering the activation energy needed. With a catalyst, more collisions result in a reaction, so the rate of reaction increases. Different reactions need different catalysts.

Question 17

Why are catalysts important to the industry?

Answer 17

Catalysts are important in industry because they reduce costs.