Question

1. a student has a 1 g sample of each of the following compounds: licl, kf, lif, and nacl. arrange these compounds in order of increasing number of moles.

Explanation:

Step1: Calculate molar masses

Molar mass of \( \text{LiCl} \): \( \text{Li} (6.94) + \text{Cl} (35.45) = 42.39 \, \text{g/mol} \)
Molar mass of \( \text{KF} \): \( \text{K} (39.10) + \text{F} (19.00) = 58.10 \, \text{g/mol} \)
Molar mass of \( \text{LiF} \): \( \text{Li} (6.94) + \text{F} (19.00) = 25.94 \, \text{g/mol} \)
Molar mass of \( \text{NaCl} \): \( \text{Na} (22.99) + \text{Cl} (35.45) = 58.44 \, \text{g/mol} \)

Step2: Calculate moles for 1g

Moles \( = \frac{\text{mass}}{\text{molar mass}} \). For 1g:
\( \text{LiCl} \): \( \frac{1}{42.39} \approx 0.0236 \, \text{mol} \)
\( \text{KF} \): \( \frac{1}{58.10} \approx 0.0172 \, \text{mol} \)
\( \text{LiF} \): \( \frac{1}{25.94} \approx 0.0386 \, \text{mol} \)
\( \text{NaCl} \): \( \frac{1}{58.44} \approx 0.0171 \, \text{mol} \)

Step3: Order by moles (increasing)

Compare moles: \( \text{NaCl} (0.0171) < \text{KF} (0.0172) < \text{LiCl} (0.0236) < \text{LiF} (0.0386) \)

Answer:

\( \text{NaCl} < \text{KF} < \text{LiCl} < \text{LiF} \)