Need help with Compounds 01? Ask our AI Tutor!

AI Tutor - Lucy

Connecting with Tutor...

Please wait while we establish connection

Hi! I'm Lucy, your AI tutor. How can I help you with Compounds 01 today?

now

Science Quiz - Compounds 01 (Questions)

Compounds are formed when elements join together. In KS3 Science, students discover how different atoms bond to make new substances with unique properties and uses.

Explore the Topic →

(quiz starts below)

Fascinating Fact:

Capsaicin, the compound in chillies, tricks your brain into thinking your mouth is on fire.

In KS3 Science, you’ll explore compounds, how atoms bond chemically to form them, and why compounds often behave very differently from the elements they are made from.

Key Terms

Compound: A substance made when two or more elements are chemically bonded together.
Chemical Bond: The force that holds atoms together in compounds and molecules.
Formula: A way of showing which atoms and how many of each are in a compound, like H?O for water.

Frequently Asked Questions (Click to see answers)

What are compounds in KS3 Science?

Compounds are substances made from two or more different elements joined by chemical bonds. An example is carbon dioxide, made from carbon and oxygen.

How are compounds different from elements?

Elements are pure substances with one type of atom, while compounds contain atoms of different elements combined, often giving them new properties.

Can compounds be separated into elements?

Compounds can only be separated into their elements through chemical reactions, unlike mixtures, which can be separated more easily by physical methods.

Try These Related Quizzes

1.

A compound is a substance which contains .......

[ ]	only one type of atom
[ ]	only two types of atom
[ ]	two or more chemicals which can be easily separated
[ ]	two or more elements chemically joined together

2.

The number of different elements in calcium carbonate (CaCO₃) is .......

[ ]	2
[ ]	3
[ ]	4
[ ]	5

3.

Which of the following could have been formed by reacting iron with sulfur?

[ ]	Iron oxide
[ ]	Sulfuric iron
[ ]	Iron sulfide
[ ]	Sulfuric acid

4.

The formula of methane is CH₄. Which of these is true?

[ ]	A molecule of methane contains five atoms
[ ]	A molecule of methane contains five different elements
[ ]	An atom of methane contains two different elements
[ ]	Methane contains five molecules

5.

Which of these is NOT a compound?

[ ]	Carbon monoxide
[ ]	Chlorine
[ ]	Hydrochloric acid
[ ]	Propane

6.

How many atoms in the formula CuSO₄?

[ ]	3
[ ]	4
[ ]	6
[ ]	7

7.

The correct formula for carbon tetrachloride is .......

[ ]	C₃Cl
[ ]	C₄Cl
[ ]	CCl₃
[ ]	CCl₄

8.

The smallest particle of carbon dioxide (CO₂) that still has the properties of carbon dioxide is called .......

[ ]	a molecule
[ ]	a proton
[ ]	an atom
[ ]	an ion

9.

Which of these word equations is INCORRECT?

[ ]	Copper + oxygen → copper oxide
[ ]	Hydrogen + chlorine → hydrogen chlorine
[ ]	Iron + chlorine → iron chloride
[ ]	Magnesium + oxygen → magnesium oxide

10.

Which is the correct formula equation?

[ ]	Mg + O → MgO
[ ]	Mg + O₂ → MgO₂ →
[ ]	2 Mg + O₂ → Mg₂O₂
[ ]	2 Mg + O₂ → 2 MgO

You can find more about this topic by visiting BBC Bitesize - Elements, compounds and mixtures

Science Quiz - Compounds 01 (Answers)

1.

A compound is a substance which contains .......

[ ]	only one type of atom
[ ]	only two types of atom
[ ]	two or more chemicals which can be easily separated
[x]	two or more elements chemically joined together

In theory, the elements could be separated using chemical reactions but that is not always straightforward

2.

The number of different elements in calcium carbonate (CaCO₃) is .......

[ ]	2
[x]	3
[ ]	4
[ ]	5

The easy way to do this is to count the capital letters in the formula. Each element has exactly ONE capital letter. In CaCO₃, the three elements are Ca, C and O

3.

Which of the following could have been formed by reacting iron with sulfur?

[ ]	Iron oxide
[ ]	Sulfuric iron
[x]	Iron sulfide
[ ]	Sulfuric acid

There are two elements joining together so the name ends in -ide

4.

The formula of methane is CH₄. Which of these is true?

[x]	A molecule of methane contains five atoms
[ ]	A molecule of methane contains five different elements
[ ]	An atom of methane contains two different elements
[ ]	Methane contains five molecules

It contains one atom of carbon joined to four atoms of hydrogen. Can you see how you get that from the formula?

5.

Which of these is NOT a compound?

[ ]	Carbon monoxide
[x]	Chlorine
[ ]	Hydrochloric acid
[ ]	Propane

Chlorine is an element and therefore appears on the periodic table. The others do not appear on the periodic table so they cannot possibly be elements

6.

How many atoms in the formula CuSO₄?

[ ]	3
[ ]	4
[x]	6
[ ]	7

One Cu, one S, four O. If you find reading formulae difficult, don't worry, you will have plenty more practice when you study science at GCSE. There are some simple rules that need to be learned, not everyone sees them straight away

7.

The correct formula for carbon tetrachloride is .......

[ ]	C₃Cl
[ ]	C₄Cl
[ ]	CCl₃
[x]	CCl₄

The clue is in the word tetra - that means four and since it is in front of the 'chloride' bit of the name, there must be four chlorine atoms involved

8.

The smallest particle of carbon dioxide (CO₂) that still has the properties of carbon dioxide is called .......

[x]	a molecule
[ ]	a proton
[ ]	an atom
[ ]	an ion

Remember, compounds that are made from two non-metals joined together exist as molecules

9.

Which of these word equations is INCORRECT?

[ ]	Copper + oxygen → copper oxide
[x]	Hydrogen + chlorine → hydrogen chlorine
[ ]	Iron + chlorine → iron chloride
[ ]	Magnesium + oxygen → magnesium oxide

Whoever wrote it forgot to change the name of chlorine to chloride in the compound

10.

Which is the correct formula equation?

[ ]	Mg + O → MgO
[ ]	Mg + O₂ → MgO₂ →
[ ]	2 Mg + O₂ → Mg₂O₂
[x]	2 Mg + O₂ → 2 MgO

If you count up the number of atoms on each side of the equation, they are the same - two of magnesium and two of oxygen