How many grams are present in 0.02 moles of beryllium iodide (BeI_2)?

• A. 2.54 g
• B. 5.34 g
• C. 3.98 g
• D. 7.62 g

Answer: (B)

Verified step by step guidance

1. Identify the chemical formula of beryllium iodide, which is BeI\_2. This means one formula unit contains 1 atom of beryllium (Be) and 2 atoms of iodine (I).
2. Calculate the molar mass of BeI\_2 by adding the atomic masses of its elements: molar mass = atomic mass of Be + 2 × atomic mass of I. Use the periodic table values (Be ≈ 9.01 g/mol, I ≈ 126.90 g/mol).
3. Multiply the number of moles given (0.02 moles) by the molar mass of BeI\_2 to find the mass in grams. The formula is: mass (g) = moles × molar mass (g/mol).
4. Set up the calculation explicitly: mass = 0.02 moles × (9.01 g/mol + 2 × 126.90 g/mol).
5. Perform the multiplication to find the mass in grams, which will give you the amount of beryllium iodide present in 0.02 moles.