Calculate the molecular (formula) mass of the following compound: chromium(II) acetate
The correct answer and explanation is:
The molecular formula for chromium(II) acetate is Cr(C2H3O2)2\text{Cr(C}_2\text{H}_3\text{O}_2\text{)}_2, which consists of one chromium (Cr) ion and two acetate (C₂H₃O₂) ions.
Step-by-Step Calculation:
- Chromium (Cr): Chromium(II) indicates the chromium ion has a +2 charge. The atomic mass of chromium (Cr) is approximately 52.00 g/mol.
- Acetate (C₂H₃O₂): The acetate ion consists of two carbon (C) atoms, three hydrogen (H) atoms, and two oxygen (O) atoms. The atomic masses of carbon, hydrogen, and oxygen are as follows:
- Carbon (C): 12.01 g/mol
- Hydrogen (H): 1.008 g/mol
- Oxygen (O): 16.00 g/mol
- Carbon: 2×12.01=24.022 \times 12.01 = 24.02 g/mol
- Hydrogen: 3×1.008=3.0243 \times 1.008 = 3.024 g/mol
- Oxygen: 2×16.00=32.002 \times 16.00 = 32.00 g/mol
- Two Acetate Ions: Since there are two acetate ions in chromium(II) acetate, multiply the molecular mass of one acetate ion by two: 59.044×2=118.088 g/mol59.044 \times 2 = 118.088 \, \text{g/mol}
- Total Molecular Mass: Now, sum the masses of the chromium ion and the two acetate ions: 52.00 (Cr)+118.088 (2 Acetates)=170.088 g/mol52.00 \, (\text{Cr}) + 118.088 \, (\text{2 Acetates}) = 170.088 \, \text{g/mol}
Final Answer:
The molecular mass of chromium(II) acetate is 170.088 g/mol.