Your blood is slightly alkaline. Its pH is always 7.4. You would be very ill if your blood pH was higher than 7.6 or lower than 7.2.

The pH of your urine changes to help adjust blood pH:

- If your blood gets too acidic, extra acid comes out in your urine. Your urine pH gets lower.

- If your blood gets too alkaline, extra alkali comes out in your urine. Your urine pH gets higher.

A hospital patient has a blood pH of 7.5. Explain how her body tried to get the blood pH back to normal.

The table below gives the preferred soil pH of some plants.

A farmer tests the soil pH on her farm. its pH is 5.0. Suggest two crops she could try growing.

A student wants to make an indicator from red cabbage. The apparatus available to the student is listed and pictured below.

The student first heats a mixture of pure water and chopped cabbage. Name the best apparatus in which to do this.

Table A shows the pH that some animals can live in. The animals can only survive at pH that is shaded grey. Table B shows how the pH of the two lakes changed over time.

Name one animal that might have lived in Lake Y in 1970.

Which of the rocks below were formed when magma cooled more slowly?

The diagram shows the rocks in the wall of a mine.

Which rock could contain fossils?

Two students investigate some rocks. They write their results in the table below.

Which rock is probably a metamorphic rock?

A student compares the drainage of three soil samples. She uses the apparatus below. The student writes her results in a table.

Which letter of the soil is most likely to be clay soil?

A student wants to compare the amounts of air in soil samples from two fields. She uses the apparatus below.

She observes the level of water in the measuring cylinder after shaking the mixture of soil and water. The lower the water level, the greater the volume of air that was in the soil.

Name the variable that the student changes.

The diagram shows the structure of the Earth.

Which letter of the label below is the inner core?

This question is about the pH of the water in three East African Lakes.

The pH range of the water in each lake is given in the table below.

A student collected a sample of water from Lake Victoria. She added a few drops of universal indicator to the water. Use data from the table, and the diagram below, to predict the colour of this mixture.

The diagrams below show the sides of the two quarries. The quarries are on different continents. The rocks shown are sedimentary rocks. They were built up in layers. Each layer took millions of years to form.

Fossils have been found in some of the layers. They are also shown in the diagram.

Which rock in Batuan Quarry was formed in the same period as rock D in Mwamba Quarry?

The pH of an acid is _____ 7

The photograph shows some gold coins. They were made about 800 years ago in India.

The list below gives some physical properties of gold.

1. It is a good conductor of electricity

2. It melts at 1063⁰C

3. It is always shiny

4. It is a good conductor of heat.

5. It is yellow

Which one of the properties in the list best shows that gold is solid at 20⁰C?

The table shows the physical properties of four elements. Each element is represented by a letter.

Give the letter of the element in the table that has the highest melting point.

A student wants to compare the strength of four substances. She sets up the apparatus below. She adds weights until the wire break.

Identify the variable the student changes.

The table gives data about three materials that can be used to build houses.

Which of the materials in the table is the weakest when compressed?

The graph below shows how the strength of manila rope and poly(propene) ropes change as rope diameter increases.

Use the graph to work out which is stronger - 30 mm manila rope of 20 mm poly(propene) rope.

What type of mixture is orange juice if it has a pH of 3?

What type of mixture is cola drink if it has a pH of 2?

What type of mixture is sweat if it has a pH of 5?

What type of mixture is 'indigestion medicine' if it has a pH of 9?

What type of rock is granite?

What type of rock is sandstone?

What type of rock is marble?