Question

Grams, Moles, Atoms, MoleculesShow calculation setups, including units, and enter answers with correct significant figures andunits on the line(s) provided.1. Find the molar mass to 3 decimal places of (a) magnesium sulfate, (b) diphosphorus heptoxide,and (c) iron(III) hydroxide. Use these values as needed in problems 2 - 4(a)MasoMgS-Ou(b)(c)

Answer 1

To find the molar mass of each compound we need the molar masses of the elements in the compound and its chemical formula.

For magnesium sulfate, MgSO₄, there are 1 atom of magnesium, one of sulfur and 4 of oxygen. Multiply each molar mass by the number of atoms of the element and then find the sum of those products:

`\begin{gathered} Mg\to24.3\cdot1=24.3 \\ S\to32.01\cdot1=32.01 \\ O\to16.0\cdot4=64.0 \\ mm=24.3+32.0+64.0=120.310 \end{gathered}`

The molar mass of magnesium sulfate is 120.310g/mol.

For diphosphorus heptoxide, P₂O₇, there are 2 atoms of phosphorus and 7 of oxygen:

`\begin{gathered} P\to30.97\cdot2=61.94 \\ O\to16.00\cdot7=112 \\ mm=61.94+112=173.94 \end{gathered}`

The molar mass of diphosphorus heptoxide is 173.940g/mol.

For iron(III) hydroxide, Fe(OH)₃, there are 1 atom of iron, 3 of hydrogen and 3 of oxygen:

`\begin{gathered} Fe\to55.84\cdot1=55.84 \\ H\to1\cdot3=3 \\ O\to16.00\cdot3=48.00 \\ mm=55.84+3+48=106.84 \end{gathered}`

The molar mass of iron(III) hydroxide is 106.840g/mol.