(b) How many moles of KBr are present in 150 mL of a 0.112 M solution?

Verified step by step guidance

1. Identify the given values: volume of the solution (V) = 150 mL, and molarity of the solution (M) = 0.112 M.
2. Convert the volume from milliliters to liters by dividing by 1000, since 1 L = 1000 mL. This is necessary because molarity is expressed in moles per liter.
3. Use the formula for molarity: Molarity (M) = moles of solute (n) / volume of solution in liters (V).
4. Rearrange the formula to solve for the moles of solute (n): n = Molarity (M) \times volume of solution in liters (V).
5. Substitute the values into the rearranged formula to find the number of moles of KBr in the solution.

Key Concepts

Molarity

Molarity (M) is a measure of concentration defined as the number of moles of solute per liter of solution. It is expressed in moles per liter (mol/L) and is crucial for calculating the amount of solute in a given volume of solution. In this question, the molarity of the KBr solution is given as 0.112 M, indicating that there are 0.112 moles of KBr in every liter of the solution.

Volume Conversion

To solve problems involving molarity, it is often necessary to convert volumes from milliliters (mL) to liters (L), as molarity is defined in terms of liters. Since 1 L equals 1000 mL, converting 150 mL to liters involves dividing by 1000, resulting in 0.150 L. This conversion is essential for accurately applying the molarity formula.

Calculating Moles from Molarity

The number of moles of solute can be calculated using the formula: moles = molarity × volume (in liters). By substituting the values of molarity (0.112 M) and the converted volume (0.150 L) into this formula, one can determine the total moles of KBr present in the solution. This calculation is fundamental in stoichiometry and solution chemistry.