Question

what is the molar mass of magnesium sulfate, mgso₄? (use approximate atomic masses: mg=24.31 g/mol, s=32.07 g/mol, o=16.00 g/mol)
120.38 g/mol
144.69 g/mol
92.31 g/mol
72.38 g/mol

what is ratio of atoms in the molecule potassium nitrate?
k:n:o = 1:1:3
k:n:o3 = 1:1:1
k:n:o = 1:2:6
k:n:o3 = 1:2:2

Explanation:

First Sub - Question (Molar Mass of Magnesium Sulfate)

Step 1: Identify atoms and their counts

In \(MgSO_4\), there is 1 Mg atom, 1 S atom, and 4 O atoms.

Step 2: Calculate mass contribution of each atom

• Mass of Mg: \(1\times24.31\space g/mol = 24.31\space g/mol\)
• Mass of S: \(1\times32.07\space g/mol=32.07\space g/mol\)
• Mass of O: \(4\times16.00\space g/mol = 64.00\space g/mol\)

Step 3: Sum the masses

Molar mass of \(MgSO_4=24.31 + 32.07+64.00=120.38\space g/mol\)

The chemical formula of potassium nitrate is \(KNO_3\). In \(KNO_3\), the number of K atoms is 1, the number of N atoms is 1, and the number of O atoms is 3. So the ratio of K:N:O is \(1:1:3\).

Answer:

120.38 g/mol (corresponding to the first option: 120.38 g/mol)

Second Sub - Question (Atom Ratio in Potassium Nitrate)