What is the best definition of a pure substance?
A substance that consists of only one element or compound
A natural substance
A substance that consists of only one element
What is a mixture?
A mixture consists of two or more elements which are chemically joined together
A mixture consists of one or more substances that are not chemically joined together
A mixture consists of two or more substances that are not chemically joined together
Which substance can be separated from its mixture by filtration?
Water from seawater
Small stones from seawater
Salt from seawater
Which method is used to obtain copper sulfate crystals from copper sulfate solution?
Filtration
Simple distillation
Crystallisation
What happens when a mixture is heated in simple distillation?
The solute evaporates and leaves the solution
The solvent evaporates and leaves the solution
A liquid leaves the solution
Which method is used to obtain pure water from salt solution?
Fractional distillation
In chromatography, what is the mobile phase?
The substance in the spots
The paper
The solvent that moves through the paper
Which substance can be separated from its mixture with water by fractional distillation?
Sand
Sodium chloride (salt)
Ethanol
A mixture of three substances is separated by fractional distillation. Which substance is collected at the bottom of the column?
The substance with the highest boiling point
The substance with the lowest boiling point
The substance with the boiling point that is neither highest nor lowest
In chromatography, how many spots are produced by a pure substance?
1
2
3