Question

1 multiple choice 1 point which of the following is a chemical reaction? sodium and chlorine atoms bond to form salt molecules ice melts to form water carbon dioxide freezes to form dry ice salt and water mix to form salt water 2 multiple choice 1 point in the equation shown, what are the reactants? 2h₂ + o₂ → 2h₂o hydrogen atoms hydrogen and oxygen molecules water molecules ice crystals

Explanation:

1. A chemical reaction involves the formation of new substances with different chemical properties. Sodium and chlorine atoms bonding to form salt molecules is a chemical reaction as new chemical bonds are formed. Melting ice, freezing carbon - dioxide, and mixing salt and water are physical changes.
2. In a chemical equation of the form $aA + bB

ightarrow cC$, the substances on the left - hand side ($A$ and $B$) are reactants. In the equation $2H_2+O_2
ightarrow2H_2O$, hydrogen and oxygen molecules are on the left - hand side and are thus the reactants.

Answer:

1. Sodium and chlorine atoms bond to form salt molecules
2. Hydrogen and oxygen molecules