What is the approximate percent by mass of potassium (K) in potassium bicarbonate (KHCO3)?

• A. 52%
• B. 23%
• C. 11%
• D. 39%

Answer: (D)

Verified step by step guidance

1. Step 1: Identify the chemical formula of potassium bicarbonate, which is KHCO\_3, and list the atomic masses of each element involved: potassium (K), hydrogen (H), carbon (C), and oxygen (O).
2. Step 2: Calculate the molar mass of potassium bicarbonate by summing the atomic masses of all atoms in the formula: \( M_{KHCO_3} = M_K + M_H + M_C + 3 \times M_O \).
3. Step 3: Calculate the mass contribution of potassium (K) alone, which is just its atomic mass \( M_K \).
4. Step 4: Use the formula for percent by mass of potassium in the compound: \[ \text{Percent by mass of K} = \left( \frac{M_K}{M_{KHCO_3}} \right) \times 100\% \].
5. Step 5: Substitute the atomic masses into the formula and perform the division and multiplication to find the approximate percent by mass of potassium in potassium bicarbonate.