Knowledge about what products are produced in a chemical reaction is obtained by:

• inspecting the chemical equation.

• balancing the chemical equation.

• laboratory analysis.

• writing a word equation.

A chemical reaction has NOT occurred if the products have:

• the same mass as the reactants.

• less total bond energy than the reactants.

• more total bond energy than the reactants.

• the same chemical properties as the reactants.

Which observation does NOT indicate that a chemical reaction has occurred?

• formation of a precipitate

• production of a gas

• evolution of heat and light

• change in total mass of substances

A solid produced by a chemical reaction in solution that separates from the solution is called:

• a. a precipitate.

• b. a reactant.

• c. a molecule.

• d. the mass of the product.

After the correct formula for a reactant in an equation has been written, the:

• subscripts are adjusted to balance the equation.

• formula should not be changed.

• same formula must appear as the product.

• symbols in the formula must not appear on the product side of the equation.

In writing an equation that produces hydrogen gas, the correct representation of hydrogen gas is:

• H.

• H2.

• OH.

• 2H.

What is the small whole number that appears in front of a formula in a chemical equation?

• a. a subscript

• b. a superscript

• c. a ratio

• d. a coefficient

To balance a chemical equation, it may be necessary to adjust the:

• coefficients.

• subscripts.

• formulas of the products.

• number of products.

According to the law of conservation of mass, the total mass of the reacting substances is:

• always more than the total mass of the products.

• always less than the total mass of the products.

• sometimes more and sometimes less than the total mass of the products.

• always equal to the total mass of the products.

A chemical equation is balanced when the:

• coefficients of the reactants equal the coefficients of the products.

• same number of each kind of atom appears in the reactants and in the products.

• products and reactants are the same chemicals.

• subscripts of the reactants equal the subscripts of the products.