KS3 Science Quiz - Mixtures 01 (Questions)

Test your knowledge of mixtures in this KS3 Science quiz. Alloys are mixtures of metals. Alloying one metal with other metal(s) or non-metal(s) often enhances (improves) its properties. For example, steel is more malleable than iron, its primary element. There are many types of steel, one of the most common is mild steel which is an alloy of iron with a small quantity of the non-metal carbon. Another important group of alloys is the stainless steels, which resist corrosion (don't go rusty). These are mainly iron that has been alloyed with the metals chromium and nickel, together with small quantities of other metals and non metals. Many foods are emulsions. An emulsion is a mixture of an oil and water. Adding an emulsifier can make these very stable.

A property of many mixtures is that they can be easily separated into their component parts. One example that is usually done in school is to separate sulfur and iron filings. This is very simple as you can just use a magnet. A mixture of a solid dissolved into a liquid e.g. brine (salty water) can be separated using evaporation whilst mixtures of liquids with different boiling points can be separated using distillation.

1. Which of these substances is a mixture?
[ ] Oxygen
[ ] Salt
[ ] Sea water
[ ] Water
2. The best description of a mixture is .......
[ ] A lot of substances jumbled together
[ ] One substance on its own
[ ] Two or more substances added together which can often be easily separated
[ ] Two or more substances chemically joined together
3. Air is a mixture of different gases. Which list consists of gases present in the air?
[ ] Hydrogen, oxygen, carbon dioxide
[ ] Nitrogen, hydrogen, carbon dioxide
[ ] Nitrogen, oxygen, carbon dioxide
[ ] Nitrogen, oxygen, hydrogen
4. How would you separate a mixture of iron filings and sulfur?
[ ] Filter
[ ] Use a magnet
[ ] Use a sieve
[ ] Use tweezers
5. Alloys are mixtures of metals. Which is NOT an alloy?
[ ] Brass
[ ] Bronze
[ ] Chromium
[ ] Solder
6. A pure substance has a melting point which is always .......
[ ] Higher than its freezing point
[ ] Higher than its boiling point
[ ] Different
[ ] The same
7. Which of the following is NOT a mixture?
[ ] Coca cola
[ ] Crude oil
[ ] Methane
[ ] Milk
8. The name given to the liquid which dissolves the solid in a solution is .......
[ ] Distillate
[ ] Saturated
[ ] Soluble
[ ] Solvent
9. The method used to separate coloured dyes in ink is .......
[ ] Chromatography
[ ] Distillation
[ ] Evaporation
[ ] Filtration
10. In a solution made by dissolving a solid in a liquid, the hotter the solvent .......
[ ] No more of the soluble solid dissolves
[ ] The less the solute dissolves
[ ] The quicker the soluble solid dissolves
[ ] The slower the solute dissolves
KS3 Science Quiz - Mixtures 01 (Answers)
1. Which of these substances is a mixture?
[ ] Oxygen
[ ] Salt
[x] Sea water
[ ] Water
Water and salt are compounds, oxygen is an element
2. The best description of a mixture is .......
[ ] A lot of substances jumbled together
[ ] One substance on its own
[x] Two or more substances added together which can often be easily separated
[ ] Two or more substances chemically joined together
If substances are chemically joined together they are much more difficult to separate. Alloys are mixtures that are usually hard to separate
3. Air is a mixture of different gases. Which list consists of gases present in the air?
[ ] Hydrogen, oxygen, carbon dioxide
[ ] Nitrogen, hydrogen, carbon dioxide
[x] Nitrogen, oxygen, carbon dioxide
[ ] Nitrogen, oxygen, hydrogen
The air is mainly nitrogen
4. How would you separate a mixture of iron filings and sulfur?
[ ] Filter
[x] Use a magnet
[ ] Use a sieve
[ ] Use tweezers
Sulfur is non-magnetic
5. Alloys are mixtures of metals. Which is NOT an alloy?
[ ] Brass
[ ] Bronze
[x] Chromium
[ ] Solder
Chromium is an element
6. A pure substance has a melting point which is always .......
[ ] Higher than its freezing point
[ ] Higher than its boiling point
[ ] Different
[x] The same
Any sample of a pure substance will have the same melting point as any other sample of the same substance. One sample of a mixture will often have a different melting point to other samples of the same mixture. If the two samples of a mixture have the same concentrations, then they will have very similar melting points
7. Which of the following is NOT a mixture?
[ ] Coca cola
[ ] Crude oil
[x] Methane
[ ] Milk
Methane is a compound
8. The name given to the liquid which dissolves the solid in a solution is .......
[ ] Distillate
[ ] Saturated
[ ] Soluble
[x] Solvent
The solid that has been dissolved is called the solute
9. The method used to separate coloured dyes in ink is .......
[x] Chromatography
[ ] Distillation
[ ] Evaporation
[ ] Filtration
Chroma comes from the Greek word for colour, khroma
10. In a solution made by dissolving a solid in a liquid, the hotter the solvent .......
[ ] No more of the soluble solid dissolves
[ ] The less the solute dissolves
[x] The quicker the soluble solid dissolves
[ ] The slower the solute dissolves
There is more energy at higher temperatures