Question

1. to balance a chemical equation, it may be necessary to adjust the ______

a. coefficients b. subscripts c. superscripts d. formulas of the compounds
part 2 balancing and classifying: balance and classify the following chemical reactions. write your classification in the blank to the right. (4 pts each, unless otherwise indicated, 41 pts total)

1. __licl + br₂ → libr + __cl₂
2. __kclo₃ → kcl + __o₂
3. __n₂ + o₂ → __n₂o₅
4. __c₃h₈ + o₂ → co₂ + __h₂o
5. __ca(oh)₂ + h₃po₄ → ca₃(po₄)₂ + __h₂o
6. write the chemical equation for the following reaction. then balance and classify. (9 pts)

aqueous potassium hydroxide reacts with aqueous copper (ii) sulfate to make aqueous copper (ii) hydroxide and solid potassium sulfate.

Explanation:

Question 25

To balance a chemical equation, we adjust the coefficients (the numbers in front of compounds) to ensure the same number of each atom on both sides. Subscripts (in formulas) can't be changed as they define the compound, superscripts relate to charges, and formulas of compounds are fixed. So the correct answer is A.

Step 1: Balance Cl and Li

On the left, we have 1 Li and 1 Cl in LiCl. On the right, 1 Li in LiBr and 2 Cl in Cl₂. So we need 2 LiCl to balance Cl (and Li). So put 2 in front of LiCl: \( 2\text{LiCl} + \text{Br}_2
ightarrow \text{LiBr} + \text{Cl}_2 \)

Step 2: Balance Br

Now, left has 2 Br (in Br₂), right has 1 Br in LiBr. So put 2 in front of LiBr: \( 2\text{LiCl} + \text{Br}_2
ightarrow 2\text{LiBr} + \text{Cl}_2 \)

Step 3: Check Cl

Left: 2 Cl (from 2 LiCl), right: 2 Cl (from Cl₂). Balanced. Classification: Single - displacement (one element replaces another in a compound)

Step 1: Balance O

Left: 3 O in KClO₃, right: 2 O in O₂. The least common multiple of 3 and 2 is 6. So put 2 in front of KClO₃ (gives 6 O) and 3 in front of O₂ (gives 6 O): \( 2\text{KClO}_3
ightarrow \text{KCl} + 3\text{O}_2 \)

Step 2: Balance K and Cl

Left: 2 K and 2 Cl (from 2 KClO₃), right: 1 K and 1 Cl in KCl. So put 2 in front of KCl: \( 2\text{KClO}_3
ightarrow 2\text{KCl} + 3\text{O}_2 \)

Step 3: Check

All atoms balanced. Classification: Decomposition (a compound breaks into simpler substances)

Answer:

A. coefficients

Question 26