Seawater contains approximately 600 mmol of NaCl per liter. How many grams of NaCl are present in 250 mL of seawater?

• A. 8.8 g
• B. 1.5 g
• C. 3.5 g
• D. 15.0 g

Answer: (A)

Verified step by step guidance

1. Identify the given information: seawater contains 600 mmol of NaCl per liter, and the volume of seawater is 250 mL (which is 0.250 L).
2. Calculate the number of millimoles of NaCl in 250 mL by using the proportion: \(\text{mmol NaCl} = 600 \ \text{mmol/L} \times 0.250 \ \text{L}\).
3. Convert millimoles of NaCl to moles by dividing by 1000: \(\text{moles NaCl} = \frac{\text{mmol NaCl}}{1000}\).
4. Find the molar mass of NaCl by adding the atomic masses of sodium (Na) and chlorine (Cl): \(\text{Molar mass NaCl} = 22.99 + 35.45\) g/mol.
5. Calculate the mass of NaCl in grams by multiplying the moles of NaCl by its molar mass: \(\text{mass NaCl} = \text{moles NaCl} \times \text{molar mass NaCl}\).