The contact process in an industrial method for making sulphuric acid that uses a vanadium oxide catalyst. Write two reasons why many industrial processes use a catalyst.

A teacher carefully cut some samples of metals and left them in the air. The class timed how long it took for the cut edge of the metals to go dull and recorded the results on scrap paper. The times were:

lithium: $92 \mathrm{s}$, potassium: $13 \mathrm{s}$, calcium: $2 \min 30 \mathrm{s}$, sodium $57 \mathrm{s}$

• Put the data into a table. Start by giving each column a heading.

Aiko investigates the reaction between magnesium and hydrochloric acid.

She adds a $1 \mathrm{Cm}$ length of magnesium to $25 {\mathrm{cm}}^3$ of the acid.

She measures the time it takes for all the magnesium to react.

She then repeats the experiment at different temperatures.

The table shows her results:

What is missing from the table?

Aiko investigates the reaction between magnesium and hydrochloric acid.

She adds $1 \mathrm{Cm}$ length of magnesium to $25 {\mathrm{cm}}^3$ of the acid.

She measures the time it takes for all the magnesium to react.

She then repeats the experiment at different temperatures.

The table shows her results:

Which temperature shows the fastest reaction?

Aiko investigates the reaction between magnesium and hydrochloric acid.

She adds $1 \mathrm{Cm}$ length of magnesium to $25 {\mathrm{cm}}^3$ of the acid.

She measures the time it takes for all the magnesium to react.

She then repeats the experiment at different temperatures.

The table shows her results:

Which data point does not fit the pattern? What should Aiko do with this data point?

Mary and Mia are making lemonade. They add some sugar to make it sweeter. Mary adds three sugar cubes to her lemonade. Mia adds the same mass of sugar granules to her lemonade.

Whose sugar will dissolve first? Give a reason for your answer.

Mary and Mia are making lemonade. They add some sugar to make it sweeter. Mary adds three sugar cubes to her lemonade. Mia adds the same mass of sugar granules to her lemonade.

What could Mia do to speed up the rate at which her sugar dissolves?

Mary and Mia are making lemonade. They add some sugar to make it sweeter. Mary adds three sugar cubes to her lemonade. Mia adds the same mass of sugar granules to her lemonade.

Use your ideas about particles to explain your answer to what could Mia do to speed up the rate at which her sugar dissolves?

Look at the diagram of the reactivity series. It shows some metals in order of reactivity.

Use the reactivity series to predict which of the displacement reactions below will take place.