To determine the number of moles of potassium bromide (KBr) in 68.5 mL of a 1.65 M solution, you can follow these steps:
1. Convert the volume from milliliters to liters:
- We need to convert the volume given in milliliters (mL) to liters (L) because molarity is usually expressed in moles per liter (M).
- Knowing that 1 mL is equivalent to 0.001 L, multiply the volume in milliliters by 0.001:
[tex]\[
68.5 \, \text{mL} \times 0.001 \, \frac{\text{L}}{\text{mL}} = 0.0685 \, \text{L}
\][/tex]
2. Calculate the number of moles:
- Molarity (M) is defined as the number of moles of solute (in this case, KBr) per liter of solution.
- To find the number of moles, multiply the molarity by the volume in liters:
[tex]\[
\text{Number of moles} = \text{Molarity} \times \text{Volume in liters}
\][/tex]
- Substituting the given values:
[tex]\[
\text{Number of moles} = 1.65 \, \text{M} \times 0.0685 \, \text{L} = 0.113025 \, \text{moles}
\][/tex]
Therefore, there are 0.0685 liters of solution and 0.113025 moles of potassium bromide (KBr) in 68.5 mL of a 1.65 M solution.
