Chemical change involves the formation of

Chalk, limestone, marble, eggshells and seashells are made of

A. calcium hydroxide

B. calcium oxide

C. calcium carbonate

D. calcium chloride

The conservation of mass is obtained when the total mass of reactants is equal to total mass of

A. products

B. molecules

C. protons

D. atoms

Chemical changes are

A. reversible

B. irreversible

C. interchangeable

D. non interchangeable

If baking soda or fruit salt is mixed with vinegar, there takes place a

A. chemical reaction

B. physical reaction

C. transference

D. both a and b

Burning of fossils fuel results in the production of

A. bio gas

B. oxygen

C. carbon dioxide

D. nitrogen