Chemical Changes and Structure - Rate of Reaction

Question 1

Suggest a time scale for the reaction - Rusting Ship

Answer 1

Years / Decades

Question 2

Suggest a time scale for the reaction - Fireworks

Answer 2

Seconds

Question 3

Suggest a time scale for the reaction - Milk turning Sour

Answer 3

Days

Question 4

Suggest a time scale for the reaction - oil formation

Answer 4

Millions of years

Question 5

Give the word for when a graph flattens out.

Answer 5

Plateaus

Question 6

What is the calculation for the average rate of reaction?

Answer 6

Average rate = change in volume (cm3) / time for change (min)

Question 7

In an experiment where you monitored the reaction rate by mass loss, why did the mass of the flask decrease?

Answer 7

Because there was gas given off.

Question 8

Explain how the slope of a graph varies with the reaction rate.

Answer 8

The steeper the slope, the faster the reaction.

Question 9

When looking at a graph how do you identify the end-point of a reaction?

Answer 9

The graph will plateaus at the end point of the reaction.

Question 10

What are catalysts?

Answer 10

A catalyst is a substance that increases the rate of a reaction and is left
chemically unchanged and retrievable at the end of the reaction.

Question 11

Looking at the experiment of monitoring reaction rates by volume of gas produced, how can you tell that the reaction is finished?

Answer 11

The effervescence will stop when the reaction has finished.

Question 12

State the 4 ways in which the rate of reaction can be increased.

Answer 12

By increasing the temperature.

By increasing the concentration of the reactant.

By increasing the surface area / decreasing particle size.

Through the use of a catalyst.

Question 13

Describe an experiment to monitor the rate of reaction by the change in mass of the reaction vessel.

Answer 13

Place the reaction vessel on a scale and monitor the change in mass at regular intervals.

Question 14

Describe an experiment to monitor the rate of reaction by the volume of gas produced during a reaction

Answer 14

Connect a conical flask (where the reaction is taking place) to a gas syringe with a delivering tube and measure the amount of gas given off.

or

Connect a conical flask to a upside down measuring cylinder full of water in a trough of water and measure that amount of water lost (gas given off)