Chemical Formulas and Chemical Equations

1. Which of the following correctly identifies the total number of atoms of each element involved in the chemical formula?

(NH4)2CO3

  1. 12 atomsb. 14 atoms c. 13 atomsd. 9 atoms

2. Shown here is the chemical formula for ammonia.

2NH3

The 2 in front of the chemical formula for ammonia means that there are two –

a.atoms of ammonia.b. molecules of ammonia.

c. atoms of ammonia in each molecule. d. nitrogen atoms in each molecule.

3. Because the Law of Conservation of Matter states that matter cannot be created or destroyed, in a chemical equation –

a. all of the subscripts in the formula in the reactants must equal that of the products

b.the number of atoms of each element in the reactants must be the same in the products.

c.all of the coefficients in the formula for the reactants must equal that of the products.

4. Which of the following accurately describes the number of aluminum and oxygen atoms in: 4Al2O3

a. 8 atoms of Aluminum and 12 atoms of Oxygen

b. 2 atoms of Aluminum and 3 atoms of Oxygen

c. 6 atoms of Aluminum and 7 atoms of Oxygen

d. 8 atoms of Aluminum and 3 atoms of Oxygen

Chemical Formulas and Chemical Equations

1. Which of the following correctly identifies the total number of atoms of each element involved in the chemical formula?

(NH4)2CO3

  1. 12 atomsb. 14 atoms c. 13 atomsd. 9 atoms

2. Shown here is the chemical formula for ammonia.

2NH3

The 2 in front of the chemical formula for ammonia means that there are two –

  1. atoms of ammonia.b. molecules of ammonia.

c. atoms of ammonia in each molecule. d. nitrogen atoms in each molecule.

3. Because the Law of Conservation of Matter states that matter cannot be created or destroyed, in a chemical equation –

a. all of the subscripts in the formula in the reactants must equal that of the products

  1. the number of atoms of each element in the reactants must be the same in the products.
  2. all of the coefficients in the formula for the reactants must equal that of the products.

4. Which of the following accurately describes the number of aluminum and oxygen atoms in: 4Al2O3

a. 8 atoms of Aluminum and 12 atoms of Oxygen

b. 2 atoms of Aluminum and 3 atoms of Oxygen

c. 6 atoms of Aluminum and 7 atoms of Oxygen

d. 8 atoms of Aluminum and 3 atoms of Oxygen

5. The chemical formula for the mineral dolomite is provided. CaMg(CO3)2

How many atoms of carbon are present in dolomite?

a.2 b. 3c. 6d. 8

6. Which of the following chemical equations is balanced?

a. 2HClO 2H2O + 2Cl2O

b. CuO + 2HCl 2CuCl2 + H2O

c. MgCl2 + NaF MgF2 + NaCl

d. 2C2H2 + 5O2 4CO2 + 2H2O

7. An incomplete chemical equation is given here.

__HCl + __Na2CO3 __H2CO3 + __NaCl

Which set of numbers, placed in the blanks as the coefficients, will balance the equation shown?

a.2, 2, 1, 1

b.2, 1, 2, 1

c.2, 1, 1, 2

d.1, 2, 1, 2

5. The chemical formula for the mineral dolomite is provided. CaMg(CO3)2

How many atoms of carbon are present in dolomite?

a.2 b. 3c. 6d. 8

6. Which of the following chemical equations is balanced?

a. 2HClO 2H2O + 2Cl2O

b. CuO + 2HCl 2CuCl2 + H2O

c. MgCl2 + NaF MgF2 + NaCl

d. 2C2H2 + 5O2 4CO2 + 2H2O

7. An incomplete chemical equation is given here.

__HCl + __Na2CO3 __H2CO3 + __NaCl

Which set of numbers, placed in the blanks as the coefficients, will balance the equation shown?

a. 2, 2, 1, 1

b.2, 1, 2, 1

c.2, 1, 1, 2

d.1, 2, 1, 2