Question

silicon, the second most common element in earths crust, is commonly used in semiconductors and electronics such as computers. since it is naturally found in quartz, it is processed by to heat the quartz with carbon to separate the silicon. the chemical equation is
sio₂ + 2c → si + 2co

which chemical formula(s) represents the reactants? | which chemical formula(s) represents the products?

how many of each atom is present in the reactants? | how many of each atom is present in the products?
si: | si:
o: | o:
c: | c:

is this a balanced equation (yes or no)? explain why.

extra practice 8 - 10: are the equations below balanced?

1. na + h₂o → naoh + h₂
2. fe + o₂ → fe₂o₃
3. al + o₂ → al₂o₃

Explanation:

Part 1: Analyzing the reaction $\boldsymbol{SiO_2 + 2C

ightarrow Si + 2CO}$

1. Reactants and Products

• Reactants (left of $

ightarrow$): $SiO_2$ (silicon dioxide) and $C$ (carbon).

• Products (right of $

ightarrow$): $Si$ (silicon) and $CO$ (carbon monoxide).

2. Atom Count in Reactants

• Si: 1 (from $SiO_2$).
• O: 2 (from $SiO_2$: $1 \times 2$).
• C: 2 (from $2C$: $2 \times 1$).

3. Atom Count in Products

• Si: 1 (from $Si$).
• O: 2 (from $2CO$: $2 \times 1$).
• C: 2 (from $2CO$: $2 \times 1$).

4. Is the Equation Balanced?

Yes. The number of each atom (Si: 1, O: 2, C: 2) is equal on both sides of the reaction.

Part 2: Extra Practice (Balancing Check)

8. $\boldsymbol{Na + H_2O

ightarrow NaOH + H_2}$

• Reactants: Na: 1, H: 2, O: 1.
• Products: Na: 1, H: 3 (1 from $NaOH$ + 2 from $H_2$), O: 1.
• Unbalanced (H atoms differ).

9. $\boldsymbol{Fe + O_2

ightarrow Fe_2O_3}$

• Reactants: Fe: 1, O: 2.
• Products: Fe: 2, O: 3.
• Unbalanced (both Fe and O differ).

10. $\boldsymbol{Al + O_2

ightarrow Al_2O_3}$

• Reactants: Al: 1, O: 2.
• Products: Al: 2, O: 3.
• Unbalanced (both Al and O differ).

Summary Table (for $SiO_2 + 2C

ightarrow Si + 2CO$)

Question	Answer
Products’ formulas	$Si$, $CO$
Atom count in reactants (Si, O, C)	1, 2, 2
Atom count in products (Si, O, C)	1, 2, 2
Balanced? (yes/no)	Yes (equal atoms on both sides)

Extra Practice Answers

1. Not balanced (H atoms: 2 vs. 3).
2. Not balanced (Fe: 1 vs. 2; O: 2 vs. 3).
3. Not balanced (Al: 1 vs. 2; O: 2 vs. 3).

Answer:

Part 1: Analyzing the reaction $\boldsymbol{SiO_2 + 2C

ightarrow Si + 2CO}$

1. Reactants and Products

• Reactants (left of $

ightarrow$): $SiO_2$ (silicon dioxide) and $C$ (carbon).

• Products (right of $

ightarrow$): $Si$ (silicon) and $CO$ (carbon monoxide).

2. Atom Count in Reactants

• Si: 1 (from $SiO_2$).
• O: 2 (from $SiO_2$: $1 \times 2$).
• C: 2 (from $2C$: $2 \times 1$).

3. Atom Count in Products

• Si: 1 (from $Si$).
• O: 2 (from $2CO$: $2 \times 1$).
• C: 2 (from $2CO$: $2 \times 1$).

4. Is the Equation Balanced?

Yes. The number of each atom (Si: 1, O: 2, C: 2) is equal on both sides of the reaction.

Part 2: Extra Practice (Balancing Check)

8. $\boldsymbol{Na + H_2O

ightarrow NaOH + H_2}$

• Reactants: Na: 1, H: 2, O: 1.
• Products: Na: 1, H: 3 (1 from $NaOH$ + 2 from $H_2$), O: 1.
• Unbalanced (H atoms differ).

9. $\boldsymbol{Fe + O_2

ightarrow Fe_2O_3}$

• Reactants: Fe: 1, O: 2.
• Products: Fe: 2, O: 3.
• Unbalanced (both Fe and O differ).

10. $\boldsymbol{Al + O_2

ightarrow Al_2O_3}$

• Reactants: Al: 1, O: 2.
• Products: Al: 2, O: 3.
• Unbalanced (both Al and O differ).

Summary Table (for $SiO_2 + 2C

ightarrow Si + 2CO$)

Question	Answer
Products’ formulas	$Si$, $CO$
Atom count in reactants (Si, O, C)	1, 2, 2
Atom count in products (Si, O, C)	1, 2, 2
Balanced? (yes/no)	Yes (equal atoms on both sides)

Extra Practice Answers

1. Not balanced (H atoms: 2 vs. 3).
2. Not balanced (Fe: 1 vs. 2; O: 2 vs. 3).
3. Not balanced (Al: 1 vs. 2; O: 2 vs. 3).