Mixture or Compound?
Every substance is an element, a compound or a mixture. Learn to tell them apart by looking for the chemical bond, and meet the ways to separate the substances in a mixture.
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Element, compound or mixture?
Every substance around you is one of three things: an element, a compound, or a mixture. The difference is all about whether the atoms are joined by chemical bonds. This module shows you how to tell them apart, and how to separate the substances in a mixture.
The three types
Here is what each one means:
Compound or mixture?
The key difference is the chemical bond:
Match the substance to its description
- Oxygen
- Water
- Air
- Iron
- An element: made of only oxygen atoms
- A compound: hydrogen and oxygen bonded
- A mixture: gases that are not bonded
- An element: made of only iron atoms
What is water?
Water is made of hydrogen and oxygen chemically bonded together. What type of substance is it?
- A compound
- An element
- A mixture
- An atom
Separating mixtures
Because a mixture is not chemically bonded, you can separate it by physical methods. Filtration separates an insoluble solid from a liquid. Crystallisation gets a soluble solid back by evaporating the liquid. Distillation separates a liquid from a solution, or liquids with different boiling points. Chromatography separates dissolved substances, like the dyes in an ink.
Which mixture would you use it on
- Filtration
- Crystallisation
- Distillation
- Chromatography
- Sand stirred into water, which never dissolved in the first place
- Salt dissolved in water, when it is the salt you want back
- Salty water, when it is the water you want back instead
- Whether a single black pen holds several different colours
Which are mixtures?
Select the TWO substances that are MIXTURES.
- Air
- Salt water
- Water
- Oxygen
Get the salt out
Put these steps in order to separate the salt from a mixture of salt and sand.
- Add water to dissolve the salt
- Filter out the sand, which does not dissolve
- Evaporate the water from the salt solution
- Salt crystals are left behind
Element, compound, mixture
A substance with only one type of atom is an _____. Two or more elements chemically bonded make a _____. Two or more substances that are not bonded make a _____. To separate an insoluble solid from a liquid you use _____. To get a soluble solid back from a solution you use _____.
Mixture or compound?
Tap the TWO statements that are TRUE.
- In a compound the elements are chemically bonded.
- A mixture can be separated by physical methods.
- An element is made of two or more types of atom.
- Filtration separates a soluble solid from a solution.
- Water is a mixture.
Choose the method
Choose the best answer for each situation.
- You have sand mixed into water. Which method separates out the sand?
- You want to get pure water from salt water. Which method do you use?
- Carbon dioxide is carbon and oxygen chemically bonded. What type of substance is it?
Explain the difference
In English, explain the difference between a compound and a mixture, and give an example of each. This is written in English and is not auto-marked.
- Explain what a compound is, with an example
- Explain what a mixture is, with an example
- State the key difference: chemical bonding
- Name one way to separate a mixture