Law of Conservation of Mass Homework 10-29.docx - Name: Tyandra ... - Free Printable

Let’s solve each row of the table using the Law of Conservation of Mass.

This law says:
Mass of Reactants = Mass of Products

So for each reaction, we add up the masses on the left (reactants) and set them equal to the sum on the right (products). Then we solve for the missing value.

---

Row 1:

Reactants: H₂ + O₂ → H₂O
Given: ? g + 9 g → 13.4 g

So:
? + 9 = 13.4
→ ? = 13.4 - 9 = 4.4 g

✔ Answer: 4.4 g

---

Row 2:

Reactants: CH₄ + O₂ → CO₂ + H₂O
Given: 12.2g + 14g → 6.2g + 20g

Check if mass is conserved:
Left: 12.2 + 14 = 26.2 g
Right: 6.2 + 20 = 26.2 g

It already balances! So no missing value here — but wait, looking at the table, it seems like maybe one of these values was meant to be unknown? But in the image, all are filled except Row 1, Row 3, Row 5, Row 7, Row 8.

Wait — let me recheck the table as shown:

Actually, looking again:

Row 2 has “6.2g” under CO₂ — that might be the answer they want us to find? But according to conservation, if reactants are 12.2 + 14 = 26.2, and products are CO₂ + 20g, then:

CO₂ = 26.2 - 20 = 6.2 g → which matches what’s written. So this row is complete.

But perhaps the student is supposed to verify or fill in blanks? Let’s go row by row as per the table structure.

Looking at the original worksheet layout:

The table has columns: Reaction | Reactant(s) | Product(s)

And some cells have numbers, others are blank with arrows pointing to where answers should go.

From the image description, the blanks are:

- Row 1: H₂ mass missing → we solved: 4.4 g
- Row 3: MgO mass missing → let’s do that next
- Row 5: NaCl mass missing
- Row 7: NH₃ mass missing
- Row 8: H₂O mass missing

Also, there’s a note: “Answers lie somewhere on the LAW OF CONSERVATION OF MASS!” — meaning we use that principle.

Let’s proceed row by row.

---

Row 3:

Reaction: Mg + O₂ → MgO
Given: 18.9 g + 5.7g → ? g

Total reactants: 18.9 + 5.7 = 24.6 g

So product MgO must also be 24.6 g

✔ Answer: 24.6 g

---

Row 5:

Reaction: Li + Cl₂ → LiCl
Given: ? g + 10.8g → 14.6g

So: ? + 10.8 = 14.6
→ ? = 14.6 - 10.8 = 3.8 g

✔ Answer: 3.8 g

---

Row 7:

Reaction: N₂ + H₂ → NH₃
Given: 28.6g + 2.86g → ? g

Total reactants: 28.6 + 2.86 = 31.46 g

So product NH₃ = 31.46 g

✔ Answer: 31.46 g

---

Row 8:

Reaction: C₆H₁₂O₆ → CO₂ + H₂O
Given: 31.5g → 23kg + ? kg ← Wait, units don’t match!

Hold on — look carefully:

In Row 8:
C₆H₁₂O₆ → CO₂ + H₂O
Masses given: 31.5g → 23kg + ? kg

That can’t be right — grams vs kilograms? Probably a typo in the worksheet.

Looking back at the image description:

It says:
“C₆H₁₂O₆ → CO₂ + H₂O
31.5g → 23kg + ? kg”

But that doesn’t make sense physically. Likely, it’s supposed to be grams, not kilograms.

Because 31.5g decomposing into 23kg of CO₂? Impossible.

Probably a misprint — should be 23g and ? g

Assuming that, then:

Reactant: 31.5 g
Products: 23 g + ? g

So: 31.5 = 23 + ?
→ ? = 31.5 - 23 = 8.5 g

✔ Answer: 8.5 g

*(If it really were kg, the problem would be broken — so we assume typo and use grams.)*

---

Now, double-checking all:

Row 1: 4.4 g ✔️
Row 3: 24.6 g ✔️
Row 5: 3.8 g ✔️
Row 7: 31.46 g ✔️
Row 8: 8.5 g ✔️

All follow Law of Conservation of Mass.

Final Answer:
4.4 g, 24.6 g, 3.8 g, 31.46 g, 8.5 g