Chemistry Spring Midterm Review 1

The coefficients in a chemical equation represent the

• masses, in grams, of all reactants and products.

• relative numbers of moles of reactants and products.

• number of atoms in each compound in a reaction.

• number of valence electrons involved in the reaction.

A balanced chemical equation allows one to determine the

• mole ration of any two substances in the reaction.

• energy released in the reaction.

• electron configuration of all elements in the reaction.

• mechanism involved in the reaction.

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

• coefficients.

• subscripts.

• formulas of the products.

• number of the products.

Which equation is not balanced?

• 2H₂ + O₂ --> 2H₂O

• 4H₂ + 2O₂ --> 4H₂O

• H₂ + H₂ + O₂ --> H₂O + H₂O

• 2H₂ + O₂ + H₂O

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.

Which coefficients correctly balance the formula

NH₄NO₂ --> N₂ + H₂O

• 1,2,2

• 1,1,2

• 2,1,1

• 2,2,2

When the formula equation Fe₃O₄ + Al --> Al₂O₃ + Fe is correctly balanced the coefficient of Fe is number

• 3.

• 2.

• 7.

• 9.

If one knows the mole ratio of a reactant and product in a chemical reaction, one can

• estimate the energy released in the reaction.

• calculate the speed of the reaction.

• calculate the mass of the product produced from a known mass of reactant.

• decide whether the reaction is reversible.

In what kind of reaction do two or more substances combine to form a new compound?

• decomposition reaction.

• combustion reaction.

• double-displacement reaction.

• synthesis reaction.

The units of molar mass are

• g/mol

• mol/g

• amu/mol

• amu/g