What is the percent by mass of calcium in CaBr2?

• A. 22.5%
• B. 40.0%
• C. 18.4%
• D. 11.2%

Answer: (A)

Verified step by step guidance

1. Identify the chemical formula of the compound, which is CaBr\_2, meaning it contains 1 calcium (Ca) atom and 2 bromine (Br) atoms.
2. Find the atomic masses of each element from the periodic table: calcium (Ca) is approximately 40.1 g/mol, and bromine (Br) is approximately 79.9 g/mol.
3. Calculate the molar mass of CaBr\_2 by adding the atomic mass of calcium to twice the atomic mass of bromine: \(M_{CaBr_2} = M_{Ca} + 2 \times M_{Br}\).
4. Calculate the percent by mass of calcium in CaBr\_2 using the formula: \(\% \text{Ca} = \left( \frac{M_{Ca}}{M_{CaBr_2}} \right) \times 100\%\).
5. Substitute the values into the formula and simplify to find the percent by mass of calcium in the compound.