Elements, Compounds and Mixtures worksheet
1. Which of the boxes contains:
a) Molecules of an element?
b) Molecules of a compound?
c) Atoms of an element?
d) Do any of the boxes contain a mixture? Explain your answer.
2. Look at the following substances. Circle the elements and underline the
compounds
a) Li
b) N2
c) CO
d)Cl2
e)S8
f)NaCl
3. How many elements make up each compound?
a) HCl b) CaCO3
c) HNO3
d) H2SO4
e) CH3OH
4. How many atoms are there in each of these molecules?
a) N2
b) CO2
c) O3 d) CH4
e) SO2
f) C2H4
5. Circle the molecule with the most atoms, in each pair;
a)
b)
c)
d)
HCl or POCl
NH3 or HNO3
C3H8 or C2H5OH
CH3COCH3 or C6H6
6. What is the formula for each molecules shown below
O
O
O
C
O
O
H
H
H
N
H
H
Answers on the next page.
Elements, Compounds and Mixtures worksheet - Answers
Elements, Compounds and
Mixtures - KS3 Science
1. Which of the boxes contains:
a) Molecules of an element?
b) Molecules of a compound?
c) Atoms of an element?
d) Do any of the boxes contain a mixture? Explain your answer
No, a mixture would contain two or more elements or compounds not
joined together. Like in the diagram below, which is a mixture of an
element and compound.
c
a
b
2. Look at the following substances. Circle the elements and underline the
compounds
b) Li
b) N2
c) CO
d)Cl2
e)S8
f)NaCl
3. How many elements make up each compound?
b) HCl 2 (Hydrogen & Chlorine) b) CaCO3 3 (Calcium, Carbon &
Oxygen)
c) HNO3 3 (Hydrogen, Nitrogen & Oxygen)
d) H2SO4
3 (Hydrogen, Sulfur & Oxygen) e) CH3OH 3 (Carbon, Hydrogen &
Oxygen, take care Hydrogen appears twice)!
4. How many atoms are there in each of these molecules?
b) N2 2 (both nitrogen) b) CO2 3 (1 carbon and 2 oxygen)
c) c) O3 3 (all oxygen) d) CH4 5 (1 carbon and 4 hydrogen)
Elements, Compounds and
Mixtures - KS3 Science
d) e) SO2 3 (1 sulfur and 2 oxygen) f) C2H4 6 (2 carbon and 4 hydrogen)
5. Circle the molecule with the most atoms in each pair
e)
f)
g)
h)
HCl or POCl
NH3 or HNO3
C3H8 or C2H5OH
CH3COCH3 or C6H6
6. What is the formula for each molecules shown below
O
O
O2
O
C
CO2
O
O
H
H
H
H2O
N
H
H
NH3
Elements, Compounds and
Mixtures - KS3 Science
Elements, Compounds and
Mixtures - KS3 Science