Homework Practice

Printable assignment

Mixtures in Daily Life: Solubility, Safety and Smart Experiments

Section A: Solubility and Daily Practices

Question 1mcq

A solubility graph shows how solubility changes with:

A.Colour only

B.Temperature

C.Sound

D.Container shape

Question 2mcq

If solubility of a salt decreases on cooling, crystals may form because:

A.The solution can no longer hold all dissolved solute

B.The solute disappears

C.The solvent becomes a metal

D.The salt becomes magnetic

Question 3mcq

Winnowing separates grain from husk using:

A.Chromatography

B.Centrifuge

C.Boiling point

D.Wind

Question 4mcq

Sieving works when components differ in:

A.Smell only

B.Solubility always

C.Particle size

D.Boiling point only

Question 5mcq

Evaporation is commonly used to obtain:

A.Iron from sulphur

B.Salt from seawater

C.Cream from milk

D.Dyes from ink

Question 6mcq

A sudden drop in temperature can help crystallisation because:

A.Solubility may decrease and excess solute separates

B.Solute becomes invisible permanently

C.All mixtures become elements

D.Solvent stops being matter

Section B: Laboratory Inquiry and Safe Apparatus

Question 7mcq

When heating a solution, students should:

A.Hold test tube mouth toward face

B.Taste the hot solution

C.Mix unknown chemicals randomly

D.Use proper apparatus and avoid direct contact with hot equipment

Question 8mcq

Why should goggles be used during some separation activities?

A.To increase concentration

B.To make solute heavier

C.To protect eyes from splashes or particles

D.To stop evaporation

Question 9mcq

A model distillation setup should clearly show:

A.A magnet for every mixture

B.Evaporation and condensation parts

C.Only decorative labels

D.No path for vapour

Question 10mcq

A paperfuge model demonstrates separation by:

A.Spinning

B.Sublimation

C.Dissolving

D.Boiling

Question 11mcq

A good experiment plan should include:

A.No variables

B.Only final answer

C.Only a drawing

D.Hypothesis, steps, observations and conclusion

Question 12mcq

To compare filtration and sedimentation fairly, students should:

A.Change all variables together

B.Use random mixtures each time

C.Use similar muddy water samples

D.Avoid recording time