Atoms, elements and compounds test questions
1
Which of these is the smallest particle?
An atom
A molecule
A speck of dust
2
Which of these is the correct symbol for magnesium?
MG
mg
Mg
3
Which statement about atoms and molecules is correct?
Elements always exist as separate atoms
Elements always exist as pairs of atoms called molecules
Elements and compounds can exist as molecules
4
How many different atoms are there in a compound?
One
Always two
Two or more
5
Approximately how many elements are there?
100
4
1,000,000
6
Which one is a compound?
Water
Hydrogen
Helium
7
Which of these contains two carbon atoms and six hydrogen atoms?
CH4
C2H6
C2H4
8
Which of these contains four hydrogen atoms?
CH3OH
H2O
H2O2
9
How many atoms are there in total in a molecule of sulfur trioxide, SO3?
Two
Three
Four
10
Why does air not have a definite formula?
It contains different amounts of water depending on where you are
It depends on the temperature
It is not a compound
Pure and impure chemical substances test questions
1
Does this show an element, a mixture or a compound?
Compound
Mixture
Element
2
Is water an element, compound or mixture?
Element
Compound
Mixture
3
What is the name of the process that occurs when salt is added to water and then stirred until the solid is no longer visible?
Filtration
Evaporation
Dissolving
4
Is air an element, compound or mixture?
Element
Compound
Mixture
5
In what type of substance does diffusion take place most quickly?
Solid
Liquid
Gas
6
In a solution of copper sulfate, what is the solvent?
The water
The copper sulfate
The mixture
7
What name is given to a substance that contains two types of atom that are not chemically joined together?
Element
Compound
Mixture
8
In a salt solution, what is the solute?
The water
The salty water
The salt
9
What happens to the boiling point of water when salt is added to it?
It no longer boils at exactly 100 degrees Celsius
It boils at exactly 100 degrees Celsius
It will never boil