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
Which method is usually used to separate coloured dyes from each other and identify them?
Chromatography
Where are the spots of the samples placed in chromatography?
Randomly on the piece of paper
In a vertical line on the paper
In a horizontal line on the paper
Bethan has collected a sample of seawater in a bucket from her local beach. The seawater contains water, salt and sand. Which series of separation techniques could she use to separate and collect the sand, salt and water?
Filtration followed by evaporation
Distillation followed by filtration
Filtration followed by distillation
A pigment of an ink has an Rf value of 0.75, and the solvent front has moved 8 cm. Using the following equation, what is the distance moved by the pigment?
Rf value = distance moved by pigment ÷ distance moved by solvent front
0.094 cm
10.667 cm
6 cm
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
A pigment of an ink moved 4 cm on a piece of chromatography paper, where the solvent front has moved 10 cm. What is the Rf value for the pigment?
0.4
2.5
40
A student wants to separate a mixture of ethanol, olive oil and water using the method of distillation. Ethanol has a boiling point of 78˚C, whilst the boiling point of olive oil is 300˚C. Which substance will be collected first?
Water
Ethanol
Olive oil
Which statement is true for a chemical change?
No new substances are formed
Energy is always given out or taken in, resulting in a temperature change
It is usually easy to reverse the change