S-C-8-1 Mass-Mole Conversions Worksheet and KEY - S-C-8-1 Mass ... - Free Printable

Let’s solve each problem step by step. We’ll use the molar masses from the periodic table and basic math.

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1. What is the mass of 2 grams?

This one is tricky — it says “What is the mass of 2 grams?” That doesn’t make sense as written, because grams are already a unit of mass. So if you have 2 grams, then the mass is just 2 grams.

But looking at the context (it’s a mole conversion worksheet), this might be a typo or misprint. Maybe it was meant to say:
> “What is the mass of 2 moles of [something]?”

However, since no substance is named, and it literally says “2 grams”, we must answer based on what’s written.

✔ Final Answer for #1: 2 grams

*(Note: If this was supposed to be about moles, the question is incomplete. But as written, 2 grams = 2 grams.)*

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2. What is the mass of 0.5 moles of CO₂?

Step 1: Find molar mass of CO₂
- Carbon (C) = 12.01 g/mol
- Oxygen (O) = 16.00 g/mol → O₂ = 32.00 g/mol
→ CO₂ = 12.01 + 32.00 = 44.01 g/mol

Step 2: Multiply moles by molar mass
Mass = moles × molar mass
= 0.5 mol × 44.01 g/mol = 22.005 g

The image shows “22.98 g” — that’s incorrect. Let’s double-check:

Wait — maybe they used rounded values?
If C = 12, O = 16 → CO₂ = 12 + 32 = 44 g/mol
Then 0.5 × 44 = 22.0 g

Still not 22.98. Hmm.

Actually — let’s check if it’s supposed to be something else? No, it says CO₂.

Perhaps it’s a mistake in the original sheet. But let’s calculate accurately:

Using precise values:
C = 12.011, O = 15.999 → O₂ = 31.998 → CO₂ = 44.009 g/mol
0.5 × 44.009 = 22.0045 g ≈ 22.00 g

So the correct answer should be ~22.00 g, not 22.98 g.

But wait — maybe it’s not CO₂? Or maybe it’s 0.52 moles? Let’s reverse-calculate:

If mass = 22.98 g for 0.5 moles → molar mass = 22.98 / 0.5 = 45.96 g/mol — which isn’t CO₂.

Conclusion: The given answer “22.98 g” is likely wrong. Correct answer is 22.00 g (using standard rounding).

But since the student may be expected to follow the worksheet’s pattern, perhaps they want us to accept their value? No — we should teach correctly.

✔ Final Answer for #2: 22.00 g

*(Note: The worksheet says 22.98 g — that appears to be an error.)*

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3. What is the mass of 0.5 moles of H₂O?

Molar mass of H₂O:
H = 1.008 × 2 = 2.016
O = 16.00
Total = 18.016 g/mol

Mass = 0.5 mol × 18.016 g/mol = 9.008 g

Worksheet says “18.01528 g/mol” — that’s the *molar mass*, not the mass of 0.5 moles!

Ah! Here’s the confusion. Question #3 says:
> “What is the mass of 0.5 moles of H₂O?”

But the answer written is “18.01528 g/mol” — which is the molar mass, not the actual mass.

That’s incorrect. They probably mixed up the question.

Correct calculation:
0.5 × 18.01528 = 9.00764 g ≈ 9.01 g

✔ Final Answer for #3: 9.01 g

*(Worksheet incorrectly lists molar mass instead of calculated mass.)*

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4. What is the mass of 0.5 moles of NaCl?

Na = 22.99 g/mol
Cl = 35.45 g/mol
NaCl = 22.99 + 35.45 = 58.44 g/mol

Mass = 0.5 × 58.44 = 29.22 g

✔ Final Answer for #4: 29.22 g

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5. How many moles are in 36 g of H₂O?

Molar mass H₂O = 18.015 g/mol (approx)

Moles = mass ÷ molar mass
= 36 g ÷ 18.015 g/mol ≈ 2.00 moles

(Exactly 2 if using 18 g/mol: 36 ÷ 18 = 2)

✔ Final Answer for #5: 2.00 moles

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6. How many moles are in 22 g of CO₂?

Molar mass CO₂ = 44.01 g/mol

Moles = 22 ÷ 44.01 ≈ 0.500 moles

(Exactly 0.5 if using 44 g/mol: 22 ÷ 44 = 0.5)

✔ Final Answer for #6: 0.500 moles

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7. How many moles are in 58.5 g of NaCl?

Molar mass NaCl = 58.44 g/mol

Moles = 58.5 ÷ 58.44 ≈ 1.001 moles ≈ 1.00 mole

(If using 58.5 g/mol exactly, then 58.5 ÷ 58.5 = 1.00)

✔ Final Answer for #7: 1.00 mole

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Now, compiling all corrected answers:

Final Answer:
1. 2 grams
2. 22.00 g
3. 9.01 g
4. 29.22 g
5. 2.00 moles
6. 0.500 moles
7. 1.00 mole