College

Determine the molarity of a solution formed by dissolving 97.7 g LiBr in enough water to yield 750.0 ml of solution.

A) 1.50 M
B) 1.18 M
C) 0.130 M
D) 0.768 M
E) 2.30 M

Provide the complete ionic equation for the reaction that occurs when aqueous solutions of K₂S and Fe(NO₃)₂ are mixed.

Answer :

Final answer:

To calculate the molarity of a solution, you find the number of moles of solute and divide by the volume of the solution in liters. For 97.7 g of LiBr dissolved in 750.0 ml, the molarity is calculated to be 1.50 M. Therefore, the correct answer is option A.

Explanation:

To determine the molarity of a solution formed by dissolving 97.7 g LiBr in 750.0 ml of solution, we first need to calculate the molar mass of LiBr. Lithium bromide (LiBr) has a molar mass of about 86.85 g/mol (6.94 g/mol for Li and 79.90 g/mol for Br).

We then use the formula: molarity (M) = moles of solute / liters of solution. First, find the number of moles of LiBr:

  1. Number of moles = mass (g) / molar mass (g/mol)
  2. Number of moles = 97.7 g / 86.85 g/mol
  3. Number of moles = 1.125 moles (approximately)

Now convert milliliters to liters:

  1. Liters of solution = 750.0 ml / 1000 ml/L
  2. Liters of solution = 0.750 L

Finally, calculate the molarity:

  1. Molarity (M) = 1.125 moles / 0.750 L
  2. Molarity (M) = 1.50 M

Thus, the molarity of the LiBr solution is 1.50 M, which corresponds to option A.

Other Questions