Question

1. choose the best answer.

which type of reaction is this?
co₂(g) + h₂(g) → co(g) + h₂o(g)
○ redox
○ precipitation
○ acid - base

1. choose the best answer.

what is the balanced equation for the following reaction?
butane (c₄h₁₀) + oxygen →
○ 2c₄h₁₀ + 10o₂ → 8co₂ + 2h₂o
○ 2c₄h₁₀ + 13o₂ → 8co₂ + 10h₂o
○ c₄h₁₀ + 13o₂ → 8co₂ + 2h₂o
○ c₄h₁₀ + 13o₂ → 4co₂ + 4h₂o

Explanation:

Question 3

Step1: Analyze reaction type

Redox reactions involve electron transfer (oxidation state changes). Precipitation reactions form insoluble solids. Acid - base reactions involve proton transfer. In $\ce{CO_{2}(g) + H_{2}(g) -> CO(g) + H_{2}O(g)}$, C in $\ce{CO_{2}}$ has +4 oxidation state, in $\ce{CO}$ it has +2 (reduction). H in $\ce{H_{2}}$ (0) is oxidized to +1 in $\ce{H_{2}O}$. So it's a redox reaction. Precipitation: no solid formed. Acid - base: no proton transfer.

Step2: Eliminate other options

Precipitation reaction needs a solid product, which is not present here. Acid - base reaction involves acids (proton donors) and bases (proton acceptors), not seen here. So only redox fits.

Step1: Balance C atoms

Butane is $\ce{C_{4}H_{10}}$. For 1 $\ce{C_{4}H_{10}}$, we need 4 $\ce{CO_{2}}$. But to balance H, $\ce{C_{4}H_{10}}$ has 10 H, so we need 5 $\ce{H_{2}O}$ (since each $\ce{H_{2}O}$ has 2 H). But usually we use even coefficients. So multiply $\ce{C_{4}H_{10}}$ by 2: $2\ce{C_{4}H_{10}}$. Now we have 8 C and 20 H.

Step2: Balance H and O

8 C means 8 $\ce{CO_{2}}$. 20 H means 10 $\ce{H_{2}O}$ (since $20\div2 = 10$). Now calculate O: in 8 $\ce{CO_{2}}$: $8\times2 = 16$ O, in 10 $\ce{H_{2}O}$: $10\times1 = 10$ O. Total O: $16 + 10=26$. Since $\ce{O_{2}}$ is diatomic, number of $\ce{O_{2}}$ molecules: $26\div2 = 13$. So the balanced equation is $2\ce{C_{4}H_{10}}+13\ce{O_{2}}->8\ce{CO_{2}}+10\ce{H_{2}O}$.

Step3: Check other options

First option: H in products: $2\times2 = 4
eq20$ (from 2 $\ce{C_{4}H_{10}}$). Third option: C: 1 $\ce{C_{4}H_{10}}$ gives 8 $\ce{CO_{2}}$ (C not balanced). Fourth option: C: 1 $\ce{C_{4}H_{10}}$ gives 4 $\ce{CO_{2}}$ (C not balanced). Second option matches the balanced equation.

Answer:

A. redox

Question 4