Final answer:
The number of moles of lithium in the diluted solution remains 0.500 mol after tripling the volume of the solution to 3.00L because dilution does not change the total number of moles, although it changes the concentration. The correct answer is option (a) 0.500 mol.
Step-by-step explanation:
When determining the number of moles of lithium (Li) in a diluted solution, we start with the initial concentration and volume of the solution. The original solution is 1.00L of 0.500M LiBr. Molarity (M) is defined as moles of solute per liter of solution (mol/L). Initially, there are 0.500 moles of LiBr per liter.
To find the moles of LiBr in the original solution before dilution, we use the formula:
- Moles of solute = Molarity (M) × Volume (L)
This yields:
- 0.500 mol/L × 1.00 L = 0.500 mol of LiBr
When the solution is tripled by dilution, the volume becomes 3.00 L but the number of moles of LiBr stays the same, because dilution only affects concentration, not the number of moles. Therefore, even after the solution volume is tripled to 3.00 L, there are still 0.500 mol of LiBr present.
Since LiBr dissociates into Li+ and Br− in solution, we can infer that there are 0.500 mol of Li+. Thus, the correct answer is option (a) 0.500 mol.