chemistry III

the substance formed when little sodium chloride is stirred in plenty of water is called a

A.suspension

B.solvent

c.solution

d.solute

• A

• B

• C

• D

Answer explanation

a solution is a uniform mixture of two or more substances.

A solute is a dissolved substance

A solvent is a substance that dissolves a solute

A suspension is a liquid containing small particles of a solid spread throughout it and which settle on standing

which one of the following processes is used in the conversion of oil to fat?

a.saponification

b.dehydration

c.hydrogenation

d.polymerisation

• a

• b

• c

• d

which one of the following substances when mixed with water conduct electricity?

a.kerosene

b.hydrogen chloride

c.glucose

d.carbon tetrachloride

• a

• b

• c

• d

Answer explanation

it dissolves in water to form H⁺ and Cl^- ions which conduct electricity

HCl + water -> H⁺_(aq) + Cl^-_(aq)

which one of the following alloys can be used for make surgical blades?

a.brass

b.bronze

c.solder

d.steel

• a

• b

• c

• d

Answer explanation

steel doesn't rust. it is made up of iron + carbon

a mixture of iron and sulphur was heated. which one of the following is true about the product?

a.the product is soluble in water

b.the product reacts with acids to produce hydrogen sulphide

C.the product reacts with acids to produce hydrogen

d.the composition of the products can be separated using a magnet

• a

• b

• c

• d

which one of the following processes increases the amount of nitrogen in the atmosphere?

a.photosynthesis

b.haber process

c.respiration

d.denitrification

• a

• b

• c

• d

which one of the following zinc solutes is an insoluble salt?

a.ZnCO ₃

b.ZnSO ₄

C.ZnCl ₂

d.Zn(NO ₃) ₂

• a

• b

• c

• d

Answer explanation

all xarbonates are insoluble except those of LI, K and NH ₄⁺

B. all soluble except Pb and Ba sulphates

c. all soluble except Pb and Ag chloride

d.all nitrates are soluble

the similarly between sulphur dioxide and carbon dioxide is that both

a.are reducing agents

b.turn lime water milky

c.dissolve in water to form acids

d.turn potassium dichromate solution green

• a

• b

• c

• d

which one of the following is used as a catalyst during laboratory preparation of oxygen?

a.iron

b.platinum

c.magnesium(IV) oxide

d. vanadium(V) oxide

• a

• b

• c

• d

Answer explanation

it is prepared in the laboratory by the réaction

2H₂O_2(aq) -> O_2(g)+ 2H₂O_(l)

which one of the following acids, when in a dilute solution have a pH of about 1?

a.citric acid

b.ethanoic acid

c.carbonic acid

d.hydrochloric acid

• a

• b

• c

• d