Rocks
What are the three main types of rock?
Igneous, sedimentary, and metamorphic.
What does the pH scale measure?
It measures how acidic or alkaline a substance is
What is an indicator used for?
An indicator is used to show whether a substance is acidic, neutral, or alkaline and shows a clear colour change.
What happens in a neutralisation reaction?
An acid reacts with an alkali to make salt and water.
How are sedimentary rocks formed?
They are formed when layers of sediment build up and become compacted over time.
What pH number is neutral, and what substance is a common example of this pH?
pH 7 is neutral, and water is a common example.
What colour does universal indicator turn in a strong acid?
Red
Why is neutralisation useful in farming?
Farmers use it to reduce acidity in soil.
What is the difference between magma and lava in the formation of igneous rocks?
Magma is molten rock underground, while lava is molten rock on the Earth’s surface.
What pH range do acids have, and what pH range do alkalis have?
Acids have a pH below 7, while alkalis have a pH above 7.
What colour does litmus paper turn in an alkali?
Blue
A scientist adds an alkali to an acidic spill until the pH reaches 7. Why has the scientist done this?
The alkali neutralises the acid and makes the spill safer.
Which type of rock is usually the most porous, and what does porous mean?
Sedimentary rocks are usually the most porous. Porous means the rock has tiny spaces or holes that can hold water or air.
Give one example of a common household acid and one example of a common household alkali.
e.g. Lemon juice is an acid, and soap is an alkali.
A solution turns universal indicator green. What does this tell you about the solution's pH?
The solution is neutral and has a pH of 7.
What two types of substances are needed for neutralisation and give examples?
An acid and an alkali e.g. hydrochloric acid and sodium hydroxide.
A rock contains fossils and visible layers. Which type of rock is it most likely to be, and why?
It is most likely a sedimentary rock because sedimentary rocks form in layers and can trap fossils.
Give one example of a common lab acid and one example of a common lab alkali.
e.g. Hydrochloric acid is a common lab acid, and sodium hydroxide is a common lab alkali.
A student tests two liquids with universal indicator. Liquid A turns orange and Liquid B turns purple.
Liquid B is more alkaline because purple shows a higher pH than orange.
Nitric acid reacts with sodium hydroxide. What are the products of this neutralisation reaction?
Salt (sodium nitrate) and water.