How many grams are present in 7.8 moles of NaCl?

• A. 273.0 g
• B. 455.4 g
• C. 7.8 g
• D. 182.0 g

Answer: (B)

Verified step by step guidance

1. Identify the given quantity and what is asked: You have 7.8 moles of NaCl and need to find the mass in grams.
2. Recall the relationship between moles and mass: mass (g) = moles × molar mass (g/mol).
3. Calculate the molar mass of NaCl by adding the atomic masses of sodium (Na) and chlorine (Cl). Use the periodic table values: Na ≈ 22.99 g/mol, Cl ≈ 35.45 g/mol.
4. Multiply the number of moles (7.8 moles) by the molar mass of NaCl to find the mass in grams.
5. Write the final expression: \(\text{mass} = 7.8 \times (22.99 + 35.45)\) and solve to get the mass in grams.