Here are the step-by-step solutions for each question on your worksheet.
1. How many Mr. Kohlers are in 11.68 moles of Kohlers?
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Step 1: Identify the conversion factor. One mole is equal to Avogadro's number, which is $6.02 \times 10^{23}$.
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Step 2: Multiply the number of moles by Avogadro's number.
$$11.68 \times (6.02 \times 10^{23})$$
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Step 3: Calculate the result.
$$11.68 \times 6.02 = 70.3136$$
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Step 4: Adjust to scientific notation and round to 3 significant figures (based on 6.02).
$$70.3136 \times 10^{23} = 7.03 \times 10^{24}$$
2. How many moles of Na are in 5.95 moles of $\text{Na}_2\text{SO}_4$?
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Step 1: Look at the chemical formula: $\text{Na}_2\text{SO}_4$. The subscript "2" next to Na means there are 2 moles of Sodium (Na) for every 1 mole of the whole compound.
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Step 2: Multiply the given moles of the compound by 2.
$$5.95 \text{ moles} \times 2 = 11.9 \text{ moles}$$
3. How many moles of $\text{SO}_4$ are in 5.95 moles of $\text{Na}_2\text{SO}_4$?
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Step 1: Look at the formula again: $\text{Na}_2\text{SO}_4$. There is no number written after the $\text{SO}_4$ group, which implies there is exactly 1 mole of sulfate ($\text{SO}_4$) for every 1 mole of the compound.
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Step 2: Since the ratio is 1:1, the amount stays the same.
$$5.95 \text{ moles} \times 1 = 5.95 \text{ moles}$$
4. How many atoms of Na are in 5.95 moles of $\text{Na}_2\text{SO}_4$?
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Step 1: First, find out how many *moles* of Na there are (we did this in Question 2).
$$5.95 \text{ moles of compound} \times 2 = 11.9 \text{ moles of Na}$$
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Step 2: Convert those moles into atoms using Avogadro's number ($6.02 \times 10^{23}$).
$$11.9 \times (6.02 \times 10^{23})$$
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Step 3: Calculate the result.
$$11.9 \times 6.02 = 71.638$$
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Step 4: Convert to scientific notation and round to 3 significant figures.
$$71.638 \times 10^{23} = 7.16 \times 10^{24} \text{ atoms}$$
5. How many ions of $\text{SO}_4$ are in 5.95 moles of $\text{Na}_2\text{SO}_4$?
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Step 1: Find the moles of $\text{SO}_4$ (we did this in Question 3). It is 5.95 moles.
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Step 2: Convert those moles into ions using Avogadro's number.
$$5.95 \times (6.02 \times 10^{23})$$
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Step 3: Calculate the result.
$$5.95 \times 6.02 = 35.819$$
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Step 4: Convert to scientific notation and round to 3 significant figures.
$$35.819 \times 10^{23} = 3.58 \times 10^{24} \text{ ions}$$
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Final Answer:
1. $7.03 \times 10^{24}$ Mr. Kohlers
2. $11.9$ moles of Na
3. $5.95$ moles of $\text{SO}_4$
4. $7.16 \times 10^{24}$ atoms of Na
5. $3.58 \times 10^{24}$ ions of $\text{SO}_4$
Parent Tip: Review the logic above to help your child master the concept of mole worksheet.
