Question

1. next, predict the mass of the solid that would remain if reaction #2 occurs when baking soda decomposes.

balance reaction #2.
$\boldsymbol{?}\\ \ce{nahco_{3}(s) \
ightarrow \boldsymbol{?}\\ \ce{na(s)} + \boldsymbol{?}\\ \ce{h_{2}(g)} + \boldsymbol{?}\\ \ce{c(s)} + \boldsymbol{?}\\ \ce{o_{2}(g)}}$
choices:
1 2 3 4

Explanation:

Step1: Balance Na atoms

$$2\text{NaHCO}_3(s) ightarrow 2\text{Na}(s) + \text{H}_2(g) + \text{C}(s) + \text{O}_2(g)$$

Step2: Balance H atoms

H is already balanced (2 on each side).

Step3: Balance C atoms

C is already balanced (1 on each side).

Step4: Balance O atoms

Adjust O₂ coefficient:

$$2\text{NaHCO}_3(s) ightarrow 2\text{Na}(s) + \text{H}_2(g) + 2\text{C}(s) + 3\text{O}_2(g)$$

Verify all atoms:

• Na: 2 on both sides
• H: 2 on both sides
• C: 2 on both sides
• O: 6 on both sides

Answer:

The coefficients (from left to right) are 2, 2, 1, 2, 3. The solid products are $\text{Na}(s)$ and $\text{C}(s)$; their total molar mass per 2 moles of $\text{NaHCO}_3$ is $(2\times22.99) + (2\times12.01) = 70.00$ g. For 1 mole of $\text{NaHCO}_3$ (84.01 g), the remaining solid mass is 35.00 g.