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What happens when salty water is boiled?

• The salt becomes a new compound and water evaporates as it has a low boiling point

• The water evaporates and the salt remains in the beaker as it has a high melting point

• The water becomes a new compound and evaporates while salt remains in the beaker

• The water will disappear and the salt remains in the beaker as it is a solid

Which of the following separations cannot be carried out using a centrifuge? The separation of:

• water from wet clothes

• cream from milk

• red blood cells from plasma

• salt from sea water

What happens when sugar is mixed with water?

• The sugar and water become a new compound that can be separated by crystallization

• The sugar dissolves as it is a solid and can be separated by crystallization

• The sugar and water become a mixture that can be separated by crystallization

• The sugar and water become a mixture that can be separated by filtration

Which of the following is a correct statement about distillation

• The components of the mixture have different densities

• The components of the mixture have different melting points

• The components of the mixture have different boiling points

• The components of the mixture form a heterogeneous mixture

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

The table below list four liquids with four different densities. Liquid 1,2,3 and 4 are immiscible and you are asked to separate them using a decantation funnel. In what order would the liquids form layers from TOP to BOTTOM?

• 3, 2, 1, 4

• 4, 1, 2, 3

• 1, 2, 3, 4

• 3, 2, 4, 1

Matter can be classified by analyzing its composition as it is shown in the diagram. Steel is a material that contains two elements: iron (Fe) and carbon (C). Two different samples of steel have different quantities of these two elements, but both have uniform composition. Using the diagram above, how would you classify steel?

• As pure substance, because it has uniform composition and it is a compound

• As a heterogeneous mixture, because is formed by two different elements

• As a homogeneous mixture, because is formed by two different elements and it is uniform

• As pure substance, because different samples have different composition

What is the correct order for obtaining salt from a mixture of sand and salt?

• Dissolving in water - filtration – evaporation

• Evaporation - filtration - dissolving in water

• Filtration - dissolving in water - evaporation

• Dissolving in water – evaporation - filtration

The process used to separate heterogeneous mixtures of solids and liquids is called

• filtration

• crystallization

• distillation

• chromatography

The formation of pure solid particles of a substance from a solution is called

• filtration

• crystallization

• distillation

• chromatography

Complete the sentence:

___________ allows to separate the fine flour particles from bigger impurities (lumps).

• Filtration

• Decantation

• Sieving

• Magnetism