Question

3 multiple answer 20 points identify the examples that are chemical changes. ice melting water evaportating into steam water reacting with oxygen iron rusting

Explanation:

A chemical change is a process where one or more substances are transformed into new substances with different chemical properties.

• Ice melting is a physical change as it changes from solid to liquid without altering its chemical composition ($H_2O$ remains $H_2O$).
• Water evaporating into steam is also a physical change; it changes from liquid to gas, but the chemical formula ($H_2O$) stays the same.
• Water reacting with oxygen: If we consider a reaction like $2H_2O + O_2$ (though this is not a common reaction in simple terms, but if there is a reaction forming new substances), it would be a chemical change. For example, in some complex chemical processes where new compounds are formed from water and oxygen - based reactants.
• Iron rusting ($4Fe+3O_2 + 6H_2O = 4Fe(OH)_3$ which further decomposes to iron oxides) is a chemical change as iron ($Fe$) reacts with oxygen ($O_2$) and water ($H_2O$) to form new substances (iron oxides).

Answer:

C. Water reacting with oxygen, D. Iron rusting