Westonci.ca is your go-to source for answers, with a community ready to provide accurate and timely information. Join our Q&A platform to connect with experts dedicated to providing precise answers to your questions in different areas. Get detailed and accurate answers to your questions from a dedicated community of experts on our Q&A platform.

What is the percent yield of lithium hydroxide from a reaction of 7.40 g of lithium with 10.2 g of water? The actual yield was measured to be 12.1 g.

[tex]\[
2 \text{Li}_{(s)} + 2 \text{H}_2\text{O}_{(l)} \rightarrow 2 \text{LiOH}_{(aq)} + \text{H}_2(g)
\][/tex]

A. 47.4%
B. 72.5%
C. 89.0%
D. 53.1%


Sagot :

To determine the percent yield of lithium hydroxide (LiOH) from the reaction of lithium (Li) with water (H[tex]\(_2\)[/tex]O), follow these steps:

1. Identify the given data:
- Mass of lithium: [tex]\( 7.40 \text{ g} \)[/tex]
- Mass of water: [tex]\( 10.2 \text{ g} \)[/tex]
- Actual yield of lithium hydroxide: [tex]\( 12.1 \text{ g} \)[/tex]
- Molar masses (needed for calculations):
- Lithium ([tex]\( \text{Li} \)[/tex]): [tex]\( 6.94 \text{ g/mol} \)[/tex]
- Water ([tex]\( \text{H}_2\text{O} \)[/tex]): [tex]\( 18.0 \text{ g/mol} \)[/tex]
- Lithium hydroxide ([tex]\( \text{LiOH} \)[/tex]): [tex]\( 23.94 \text{ g/mol} \)[/tex]

2. Calculate the moles of reactants (Li and H[tex]\(_2\)[/tex]O):
[tex]\[ \text{Moles of Li} = \frac{\text{Mass of Li}}{\text{Molar mass of Li}} = \frac{7.40 \text{ g}}{6.94 \text{ g/mol}} \approx 1.066 \text{ moles} \][/tex]
[tex]\[ \text{Moles of H}_2\text{O} = \frac{\text{Mass of H}_2\text{O}}{\text{Molar mass of H}_2\text{O}} = \frac{10.2 \text{ g}}{18.0 \text{ g/mol}} \approx 0.567 \text{ moles} \][/tex]

3. Determine the theoretical moles of lithium hydroxide (LiOH) produced:
According to the balanced chemical equation:
[tex]\[ 2 \text{ Li} + 2 \text{ H}_2\text{O} \rightarrow 2 \text{ LiOH} + \text{ H}_2 \][/tex]
The reaction stoichiometry shows that 2 moles of Li react with 2 moles of H[tex]\(_2\)[/tex]O to produce 2 moles of LiOH. Therefore, moles of LiOH produced should be equivalent to the moles of Li reacted considering lithium is the limiting reactant.
[tex]\[ \text{Theoretical moles of LiOH} = \text{Moles of Li} \approx 1.066 \text{ moles} \][/tex]

4. Convert the theoretical moles of lithium hydroxide to grams:
[tex]\[ \text{Theoretical yield of LiOH} = \text{Theoretical moles of LiOH} \times \text{Molar mass of LiOH} = 1.066 \text{ moles} \times 23.94 \text{ g/mol} \approx 25.53 \text{ g} \][/tex]

5. Calculate the percent yield:
[tex]\[ \text{Percent yield} = \left( \frac{\text{Actual yield}}{\text{Theoretical yield}} \right) \times 100 = \left( \frac{12.1 \text{ g}}{25.53 \text{ g}} \right) \times 100 \approx 47.4\% \][/tex]

Thus, the percent yield of lithium hydroxide is [tex]\( 47.4\% \)[/tex].

The correct answer is [tex]\( 47.4\%\)[/tex].
Thank you for choosing our platform. We're dedicated to providing the best answers for all your questions. Visit us again. Thanks for stopping by. We strive to provide the best answers for all your questions. See you again soon. Your questions are important to us at Westonci.ca. Visit again for expert answers and reliable information.