Rates Of Reaction

Question 1

How does increasing the concentration, increase the rate of the reaction?

Answer 1

There are more reactant particles to collide and form activated complexes, increasing the frequency of successful collisions.

Question 2

How does increasing the temperature increase the rate of reaction?

Answer 2

Particles have more energy to react and overcome the activation energy easier, increasing the frequency of successful collisions.

Question 3

What is heterogeneous catalysis?

Answer 3

When the catalyst and reactants are in different states.

Question 4

What is homogeneous catalysis?

Answer 4

When the catalyst and reactants are in the same state.

Question 5

What are the two requirements for a successful collision?

Answer 5

Sufficient energy to overcome the activation energy and form activated complex’s and same collision geometry.

Question 6

Name a biological catalyst.

Answer 6

Enzymes.

Question 7

How does decreasing the particle size increase the rate of reaction?

Answer 7

By decreasing the particle size, we are increasing its surface area, providing a greater surface area collisions can take place on, increasing the chance of successful collisions.

Question 8

How does using a catalyst increase the rate of reaction?

Answer 8

It speeds up the rate of the chemical reaction without being used up.

Question 9

What is the equation for the enthalpy change?

Answer 9

Δ Enthalpy = Enthalpy of Products - Enthalpy of Reactants

Question 10

What is the symbol and term of a reaction which gives out energy.

Answer 10

It ‘-‘ as it exothermic.

Question 11

What is the symbol and term for the reaction which takes in energy?

Answer 11

It is ‘+’ and is endothermic.

Question 12

What is formed when reactants collide?

Answer 12

An activated complex.

Question 13

Describe what an ‘activated complex’ is.

Answer 13

It is when reactants collide with sufficient energy to form weak, unstable bonds with the other reactant.

Question 14

What happens to a graph when the temperature is increased?

Answer 14

The peak remains the same, the graph will shift to the right. There is no change to the activation energy.

Question 15

What happens to the graph when there is an increase in concentration or reactants?

Answer 15

The new line is larger.

Question 16

What do catalysts do to the activation energy?

Answer 16

Decrease it.

Question 17

What is the effect of a catalyst on the activation energy

Answer 17

Lowers it.

Question 18

What is the effect of a catalyst on the rate of reaction?

Answer 18

Lowers it/decreases it.

Question 19

What does adding a catalyst to do the graph?

Answer 19

Shifts the activation energy line to the left to include more successful collision.

Question 20

Explain what happens to the covalent radius as it goes along the period (2).

Answer 20

The covalent radii decreases due to the increasing number of protons attracting the outermost electrons closer to yeh positive nucleus, decreasing the size.

Question 21

What happens to the covalent radius as you go down a group?

Answer 21

The covalent radii increases as there more election shells, which are further away from the nucleus, decreasing the outermost electrons attraction to the positive nucleus.

Question 22

What is the first ionisation equation of Magnesium?

Answer 22

Mg (g) -> Mg+(g) + e

Question 23

Explain what happens to the electronegativity of an atom as it goes across a period. (2)

Answer 23

The electro negativity increases, as there is an increasing number of protons which are increasingly attracted to bonding electrons.

Question 24

Explain what happens to the electronegativity going down a group. (2)

Answer 24

The electronegativity decreases because the increasing number electron shells shields the positive nucleus from bonding electrons, decreasing its attraction to bonding electrons.