Chemical Equations and Counting Atoms Review

Front

What is the chemical formula for phosphate?

Back

PO₄³⁻

Front

How many atoms are in one molecule of phosphoric acid (H₃PO₄)?

Back

7 atoms (3 H, 1 P, 4 O)

Front

What does the coefficient in a chemical formula represent?

Back

The number of molecules or formula units of that substance.

Front

How many hydrogen atoms are in 2H₂O?

Back

4 hydrogen atoms (2 x 2 = 4)

Front

What is the principle of conservation of mass in a chemical reaction?

Back

Matter is not created or destroyed; the total mass of reactants equals the total mass of products.

Front

What is the total number of atoms in the compound Mg(OH)₂?

Back

5 atoms (1 Mg, 2 O, 2 H)

Front

How do you determine the number of atoms in a compound from its chemical formula?

Back

Count the subscripts for each element and multiply by the coefficient if present.

Front

What is the significance of subscripts in a chemical formula?

Back

Subscripts indicate the number of atoms of each element in a molecule.

Front

What is the chemical formula for water?

Back

H₂O

Front

How many total atoms are in the formula 3Ca(NO₃)₂?

Back

21 atoms (3 Ca, 6 N, 18 O)