Multiple Choice
What is the molar concentration of a solution prepared by dissolving 25.75 g of NaOH in water to produce 500.0 mL of solution?
6. Chemical Quantities & Aqueous Reactions
Molarity
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What is the molarity of a 10.4% by mass glucose (C6H12O6) solution if the density of the solution is 1.03 g/mL?
A
0.72 M
B
0.48 M
C
0.65 M
D
0.59 M
Verified step by step guidance1
Start by understanding that molarity (M) is defined as the number of moles of solute (in this case, glucose) per liter of solution. The formula is: M = \( \frac{\text{moles of solute}}{\text{liters of solution}} \).
Calculate the mass of glucose in a given mass of solution. Since the solution is 10.4% by mass glucose, this means there are 10.4 grams of glucose in every 100 grams of solution.
Determine the volume of the solution using its density. Given the density is 1.03 g/mL, convert the mass of the solution (100 g) to volume: \( \text{Volume} = \frac{\text{mass}}{\text{density}} = \frac{100 \text{ g}}{1.03 \text{ g/mL}} \). Convert this volume from mL to L for use in the molarity formula.
Calculate the moles of glucose. Use the molar mass of glucose (C6H12O6), which is approximately 180.18 g/mol, to convert the mass of glucose to moles: \( \text{Moles of glucose} = \frac{10.4 \text{ g}}{180.18 \text{ g/mol}} \).
Finally, calculate the molarity of the solution by dividing the moles of glucose by the volume of the solution in liters: \( M = \frac{\text{moles of glucose}}{\text{liters of solution}} \).
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