What is the correct formula mass for Zn(NO2)2

What is the correct formula mass for Zn(NO2)2

The Correct Answer and Explanation is:

To calculate the formula mass of zinc nitrite (Zn(NO2)2), you need to find the atomic masses of all the elements in the compound and add them together.

Step-by-step Calculation:

1. Zinc (Zn):
   The atomic mass of zinc is 65.38 g/mol.
2. Nitrite (NO2):
   A nitrite ion (NO2) consists of:
   • Nitrogen (N): The atomic mass of nitrogen is 14.01 g/mol.
   • Oxygen (O): The atomic mass of oxygen is 16.00 g/mol, and there are two oxygen atoms in each NO2 ion.
   So, the molar mass of one nitrite ion (NO2) is: 14.01 (N)+2×16.00 (O)=14.01+32.00=46.01 g/mol14.01 \, (\text{N}) + 2 \times 16.00 \, (\text{O}) = 14.01 + 32.00 = 46.01 \, \text{g/mol}14.01(N)+2×16.00(O)=14.01+32.00=46.01g/mol
3. Zn(NO2)2:
   Zinc nitrite has one zinc atom (Zn) and two nitrite ions (NO2). The total formula mass is the sum of the atomic mass of zinc and the mass of two nitrite ions: 1×65.38 (Zn)+2×46.01 (NO2)=65.38+92.02=157.40 g/mol1 \times 65.38 \, (\text{Zn}) + 2 \times 46.01 \, (\text{NO2}) = 65.38 + 92.02 = 157.40 \, \text{g/mol}1×65.38(Zn)+2×46.01(NO2)=65.38+92.02=157.40g/mol

Final Answer:

The formula mass of Zn(NO2)2 is 157.40 g/mol.

Explanation:

Formula mass is simply the sum of the atomic masses of all elements in the formula, and it gives us the total mass of one mole of the compound. Each element in the compound has its specific atomic mass, which you can find on the periodic table. By multiplying the atomic mass of each element by the number of atoms of that element in the compound and then adding them together, you get the formula mass.

For Zn(NO2)2, the mass is calculated as follows:

• Zinc contributes 65.38 g/mol.
• The two nitrite ions contribute 92.02 g/mol in total.
  Thus, the overall mass is 157.40 g/mol.