Question

click to select the correct answers. click again to unselect answers. leave the incorrect answers unselected. choose all the true statements concerning the law of conservation of mass. (choose 3) a when ice melts, mass is gained since water is more dense than ice. b 2h₂ + o₂ → 2h₂o is a balanced equation. c a chemical change does not follow the law of conservation of mass. d a physical change does follow the law of conservation of mass. e a pencil breaking is an example of a physical change.

Explanation:

• Option A is false as mass is conserved when ice melts, it's just a change in state and density, not mass gain.
• Option B is true as the equation $2H_2 + O_2

ightarrow2H_2O$ has the same number of each type of atom on both sides, following mass - conservation in chemical reactions.

• Option C is false as all chemical changes follow the law of conservation of mass.
• Option D is true as physical changes also follow the law of conservation of mass since no new substances are formed and mass remains constant.
• Option E is true as a pencil breaking is a physical change where only the shape and size change, not the substance itself.

Answer:

B. $2H_2+ O_2
ightarrow2H_2O$ is a balanced equation.
D. A physical change does follow the law of conservation of mass.
E. A pencil breaking is an example of a physical change.