Answer :
To determine the molarity of the solution formed by dissolving 97.7 g of LiBr (lithium bromide) in enough water to yield 750.0 mL of solution, follow these steps:
1. Convert the Volume to Liters: The first step is to convert the volume of the solution from milliliters to liters because molarity is expressed in moles per liter.
[tex]\[
\text{Volume in liters} = \frac{750.0 \, \text{mL}}{1000} = 0.75 \, \text{L}
\][/tex]
2. Calculate the Molar Mass of LiBr: The molar mass of LiBr is given as 86.845 g/mol. This value is important for converting grams to moles.
3. Calculate the Number of Moles of LiBr: To find the number of moles of LiBr, use the formula:
[tex]\[
\text{Moles of LiBr} = \frac{\text{mass of LiBr}}{\text{molar mass of LiBr}} = \frac{97.7 \, \text{g}}{86.845 \, \text{g/mol}} \approx 1.1249928 \, \text{moles}
\][/tex]
4. Calculate the Molarity: Molarity is defined as the number of moles of solute per liter of solution. Use the formula:
[tex]\[
\text{Molarity} = \frac{\text{moles of LiBr}}{\text{volume in liters}} = \frac{1.1249928 \, \text{moles}}{0.75 \, \text{L}} \approx 1.50 \, \text{M}
\][/tex]
Thus, the molarity of the solution is approximately 1.50 M.
1. Convert the Volume to Liters: The first step is to convert the volume of the solution from milliliters to liters because molarity is expressed in moles per liter.
[tex]\[
\text{Volume in liters} = \frac{750.0 \, \text{mL}}{1000} = 0.75 \, \text{L}
\][/tex]
2. Calculate the Molar Mass of LiBr: The molar mass of LiBr is given as 86.845 g/mol. This value is important for converting grams to moles.
3. Calculate the Number of Moles of LiBr: To find the number of moles of LiBr, use the formula:
[tex]\[
\text{Moles of LiBr} = \frac{\text{mass of LiBr}}{\text{molar mass of LiBr}} = \frac{97.7 \, \text{g}}{86.845 \, \text{g/mol}} \approx 1.1249928 \, \text{moles}
\][/tex]
4. Calculate the Molarity: Molarity is defined as the number of moles of solute per liter of solution. Use the formula:
[tex]\[
\text{Molarity} = \frac{\text{moles of LiBr}}{\text{volume in liters}} = \frac{1.1249928 \, \text{moles}}{0.75 \, \text{L}} \approx 1.50 \, \text{M}
\][/tex]
Thus, the molarity of the solution is approximately 1.50 M.