Homework Practice

Printable assignment

Corrosion and Rancidity: Chemistry Around Us

Section A: Corrosion and Rusting

Question 1mcq

Rusting of iron is mainly an example of:

A.Reduction only

B.Oxidation

C.Sublimation

D.Melting

Question 2mcq

Which conditions are usually needed for rusting of iron?

A.Oxygen and moisture

B.Only dry nitrogen

C.Only sunlight

D.Only sugar

Question 3mcq

Painting iron gates helps prevent rusting because paint:

A.Blocks contact with air and moisture

B.Produces more water

C.Turns iron into gold

D.Increases oxidation

Question 4mcq

Galvanisation prevents rusting by coating iron with:

A.Zinc

B.Sodium chloride

C.Carbon dioxide

D.Copper only

Question 5mcq

Why does rusting weaken iron objects?

A.Rust is flaky and does not protect the metal underneath

B.Rust is stronger than iron

C.Rust turns iron into plastic

D.Rust makes iron more flexible

Question 6mcq

Tarnishing of silver is also linked to:

A.Photosynthesis

B.Corrosion

C.Digestion

D.Freezing

Section B: Rancidity and Prevention

Question 7mcq

Rancidity mainly affects food containing:

A.Only water

B.Only pure salt

C.Fats and oils

D.Only sand

Question 8mcq

A rancid food usually has:

A.A louder sound

B.Unpleasant smell and taste

C.A metallic shine

D.No change at all

Question 9mcq

Which method helps slow rancidity?

A.Keeping food in airtight containers

B.Adding more oxygen

C.Leaving food open in sunlight

D.Heating food repeatedly for days

Question 10mcq

Chips packets are often flushed with nitrogen because nitrogen:

A.Increases rusting

B.Reduces oxidation of oils

C.Turns oil into water

D.Acts as a strong acid

Question 11mcq

Refrigeration helps prevent rancidity by:

A.Increasing contact with oxygen

B.Making bacteria produce rust

C.Slowing down oxidation reactions

D.Changing oil into metal

Question 12mcq

Antioxidants are added to some foods to:

A.Make oxygen more reactive

B.Cause corrosion

C.Turn food into precipitate

D.Prevent or slow oxidation