Year 7 Quiz Revision

What is true of pure substances? (There may be more than one answer)

• They can be elements or compounds

• Their atoms can be separated and it is still the same substance

• Their atoms CANNOT be separated as it would no longer be the same substance

• A solution is a pure substance

Classify the following mixtures as heterogenous or homogenous

Groups:

(a) Heterogenous

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(b) Homogenous

• Solution

• Emulsion

• Suspension

• Colloid

Categorise the image as displaying either a pure substance or a mixture

Groups:

(a) Pure Substance

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(b) Mixture

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A solution consists of a ​ (a)   dissolved in a​ (b)   . The appearance of a solution is usually​ (c)   . Examples of a solution include ​ (d)   and ​ (e)   .

• solute
• solvent
• transparent
• saltwater
• cordial
• milk
• mayonnaise
• cloudy

The size of the particles in a solution are​ (a)   .

The size of the particles in a suspension are​ (b)   .

The size of the particles in a colloid are​ (c)   .

• small
• medium
• large

A suspension is a type of ​ (a)   mixture consisting of a/n ​ (b)   solid in a ​ (c)   . In a suspension the solid particles settle at the ​ (d)   of the mixture forming a ​ (e)   .

• heterogenous
• insoluble
• liquid
• bottom
• sediment
• homogenous
• soluble
• gas
• solid
• matter

Irene prepares a solution of 50 grams of salt in 5 litres of water. If Irene adds another 50 grams of salt - what happens?

• The concentration decreases

• The solution becomes saturated

• The amount of solute has increased

• The concentration increases

What of the following mixtures is a suspension?

• Sugar dissolved in water

• Whipped cream

• Sand in water

• Butter

Loocoos and Kootoos are making Gatorade using powder. Loocoos puts 50 grams of Gatorade powder in 250mL of water. Kootoos puts 100 grams of Gatorade powder in 300mL of water. Which of the below statements is true?

• Loocoos' cordial has a higher concentration

• Kootoos' cordial has a higher concentration

• Both Loocoos' cordial and Kootoos' cordial are the same concentration

• Kootoos' cordial is a saturated solution

What separation technique should be used to separate pebbles of different sizes?

• Sieving

• Magnetic separation

• Evaporation

• Filtration