Rates Of Reaction (4)

Question 1

What are the 4 things that affect a rate of reaction

Answer 1

Temperature

Concentration (pressure for gases)

Catalyst

Size of particles / surface area

Question 2

Rate of reaction equation:

Answer 2

Rate of reaction = Amount of reactant used OR amount of product formed / Time

Question 3

What are the 3 ways to measure the speed of a reaction

Answer 3

Precipitation

Change in mass

The volume of gas given off

Question 4

What is precipitation

Answer 4

When the product of the reaction is a precipitate which clouds over the solution

Question 5

How to measure precipitation

Answer 5

Observe a marker and measure how long it takes to dissapear

Question 6

How to measure change in mass

Answer 6

Do the reaction on a weight. The reaction has finished when the weight stops dropping. The quicker the weight drops, the quicker the reaction

Question 7

When should you use the change in mass measurement

Answer 7

When a gas is produced

Question 8

Which is the most accurate way to measure the rate of reaction

Answer 8

Change in mass

Question 9

The third way - ‘the volume of gas given off’ involves the use of a gas ___________ to measure the volume of gas given off. The more gas given off during a time interval, the ___________ the reaction

Answer 9

Gas syringe

Faster

Question 10

1 disadvantage of each method of measurement

Precipitation

Change in mass

Volume of gas given off

Answer 10

Precipitation: People may not degree when the marker disappears

Change in mass: Gas is released straight into the room

The volume of gas given off: If the reaction is too vigorous, you can easily blow the plunger out of the end of the syring

Question 11

What does the reaction of hydrochloric acid and marble chips demonstrate the effect of

Answer 11

The effect of breaking the solid up into smaller bits

Question 12

How to do the reaction of hydrochloric acid and marble chips

Answer 12

Fill a flask with hydrochloric acid and connect it to a delivery tube to another upside-down measuring cylinder in a trough of water. Drop marble chips in a solution of hydrochloric acid and start the timer immediately. The Co2 given off will create bubbles. You can measure the co2 given off by finding the difference between the water before and after Do the same experiment again with the same mass of marble chips but crush them up more, or change the temperature. See the difference.

Question 13

Good experiment to show the effect of catalysts

Answer 13

The decomposition of hydrogen peroxide

Question 14

How to do the decomposition of hydrogen peroxide to prove the effect of catalysts.

Answer 14

Hydrogen peroxide decomposes to form heavy water and oxygen. This is normally a slow reaction but manganese oxide speeds it up

Since oxygen is the gas given off you can just use a syringe to measure it

Question 15

What does a rate of reaction graph look like

Answer 15

This

Question 16

What is collision theory

Answer 16

The theory that a rate of reaction simply depends on how often and how hard the reacting particles collide with each other.

Question 17

How does higher temperature effect the rate of reaction

Answer 17

When temperature is increased, particles have more energy and move quicker meaning that they will collide more frequently.

Question 18

How does concentration effect the rate of reaction

Answer 18

If a solution is made more concentrated it means there are more particles of reactant around. Which makes collisions more likely.

Question 19

How does pressure effect the rate of reaction

Answer 19

In a gas, increasing the pressure means the particles are more squashed together together (compact) so they are going to collide more frequently.

Question 20

How does larger surface area effect the rate of reaction

Answer 20

If the surface area is increased then the particles around it that want to react have more area to react with, hence, more succesful collisions.

Question 21

How does a catalyst effect the rate of reaction

Answer 21

A catalyst works by giving the reacting particles a surface to stick to which increases the number of succesful collisions by lowering the activation energy

Question 22

The initial energy is known as the _______________ energy and it’s needed to break the initial bonds

Answer 22

Activation energy

Question 23

Energy must be supplied to break existing bonds - so bond breaking is an ______________ process

Answer 23

Endothermic

Question 24

Energy is released when new bonds are formes - so bond formation is an __________________ process

Answer 24

Exothermic

Question 25

In an endothermic reaction, energy is _________ ______

Answer 25

Taken in

Question 26

In an exothermic reaction, energy is ________ ______

Answer 26

Given out

Question 27

An endothermic reaction is one which _________ _____ energy from the surroundings, usually in the form of heat and shown by a ________ in temperature

Answer 27

Takes in energy

Fall

Question 28

An exothermic reaction is one which _________ _____ energy from the surroundings, usually in the form of heat and usually shown by a ________ in temperature

Answer 28

Gives out

Rise

Question 29

The overall change in energy in a reaction is called the ______________ change. It has the symbol ______

Answer 29

Enthalpy. ΔH

Question 30

Units of ΔH

Answer 30

KJ/mol

Question 31

If the reaction is exothermic, the value is _____________ because the reaction is _________ _____ energy

Answer 31

Negative

Giving out

Question 32

If the reaction is endothermic, the value is ____________ because the reaction is _________ _____ energy

Answer 32

Positive

Taking in