The chemical formula for zinc nitrate is: Zn(NO3)2 Calculate the molar mass of zinc nitrate. Round your answer to 1 decimal place.

Answer 1

Molar mass (M) is the mass of a substance (m) divided by the number of moles of a substance (n). The m will be in the units of grams (g) while n has the units of moles, so M will have the units g/mol.

Use the periodic table to find the combined molar mass of the elements that make up the compound zinc nitrate.

Zn = 65.38 g/mol

N = 14.007 g/mol

O = 15.999 g/mol

Now we look at the compound Zn(NO₃)₂

65.38 g/mol + ((14.007 g/mol + (15.999 g/mol *3))*2) =189.388 g/mol = 189.4 g/mol

Because there was a subscript 3 within the parenthesis of NO3 on the O, the molar mass of O from the periodic table must be multiplied by 3. There is also a subscript 2 attached outside of the NO3, meaning the contents in the parentheses (the molar mass of NO3) must be multiplied by 2. All of this is added to the molar mass of Zn, which has no subscript for a grand total of 189.388 g/mol which will be rounded to the first decimal place as specified in the question, which is 189.4 g/mol.

Hope this helps!