How many grams of FeSO_4 are present in a 20.0 mL sample of a 0.500 M solution?

• A. 0.560 g
• B. 0.280 g
• C. 1.40 g
• D. 2.78 g

Answer: (C)

Verified step by step guidance

1. Identify the given information: the volume of the solution is 20.0 mL and the molarity (M) of FeSO_4 is 0.500 M. Remember that molarity is defined as moles of solute per liter of solution.
2. Convert the volume from milliliters to liters because molarity uses liters: use the conversion \$1\, \text{L} = 1000\, \text{mL}\(, so \)V = \frac{20.0}{1000} = 0.0200\, \text{L}$.
3. Calculate the number of moles of FeSO_4 in the solution using the formula \(\text{moles} = M \times V\), where \(M\) is molarity and \(V\) is volume in liters.
4. Find the molar mass of FeSO_4 by adding the atomic masses of iron (Fe), sulfur (S), and oxygen (O) atoms: \(\text{Molar mass} = M_{Fe} + M_{S} + 4 \times M_{O}\).
5. Calculate the mass of FeSO_4 by multiplying the moles of FeSO_4 by its molar mass: \(\text{mass} = \text{moles} \times \text{molar mass}\). This will give you the grams of FeSO_4 in the 20.0 mL sample.