Question

practice: interpreting chemical formulas
part 1: for each chemical formula, list: (1) the elements in it and (2) how many atoms there are of each element.

1. h₂o₂
2. ba₃n₂
3. c₆h₁₂o₆
4. bacl₂
5. ch₄
6. pb(no₃)₂
7. (nh₄)₂s
8. cr(c₂h₃o₂)₂
9. mg₃(po₄)₂
10. ch₃cooh

Explanation:

Step1: Identify elements, count atoms

For $\text{H}_2\text{O}_2$: Elements are Hydrogen (H), Oxygen (O). Subscripts give atom counts: H=2, O=2.

Step2: Identify elements, count atoms

For $\text{Ba}_3\text{N}_2$: Elements are Barium (Ba), Nitrogen (N). Subscripts give atom counts: Ba=3, N=2.

Step3: Identify elements, count atoms

For $\text{C}_6\text{H}_{12}\text{O}_6$: Elements are Carbon (C), Hydrogen (H), Oxygen (O). Subscripts give atom counts: C=6, H=12, O=6.

Step4: Identify elements, count atoms

For $\text{BaCl}_2$: Elements are Barium (Ba), Chlorine (Cl). Subscripts give atom counts: Ba=1, Cl=2.

Step5: Identify elements, count atoms

For $\text{CH}_4$: Elements are Carbon (C), Hydrogen (H). Subscripts give atom counts: C=1, H=4.

Step6: Identify elements, count atoms

For $\text{Pb(NO}_3\text{)}_2$: Elements are Lead (Pb), Nitrogen (N), Oxygen (O). Multiply subscripts inside parentheses by outer subscript: Pb=1, N=$1\times2=2$, O=$3\times2=6$.

Step7: Identify elements, count atoms

For $\text{(NH}_4\text{)}_2\text{S}$: Elements are Nitrogen (N), Hydrogen (H), Sulfur (S). Multiply subscripts inside parentheses by outer subscript: N=$1\times2=2$, H=$4\times2=8$, S=1.

Step8: Identify elements, count atoms

For $\text{Cr(C}_2\text{H}_3\text{O}_2\text{)}_2$: Elements are Chromium (Cr), Carbon (C), Hydrogen (H), Oxygen (O). Multiply subscripts inside parentheses by outer subscript: Cr=1, C=$2\times2=4$, H=$3\times2=6$, O=$2\times2=4$.

Step9: Identify elements, count atoms

For $\text{Mg}_3\text{(PO}_4\text{)}_2$: Elements are Magnesium (Mg), Phosphorus (P), Oxygen (O). Multiply subscripts inside parentheses by outer subscript: Mg=3, P=$1\times2=2$, O=$4\times2=8$.

Step10: Identify elements, count atoms

For $\text{CH}_3\text{COOH}$ (rewrite as $\text{C}_2\text{H}_4\text{O}_2$): Elements are Carbon (C), Hydrogen (H), Oxygen (O). Combine equivalent element counts: C=2, H=4, O=2.

Answer:

1. $\text{H}_2\text{O}_2$: Elements - Hydrogen (H), Oxygen (O); Atom counts - H: 2, O: 2
2. $\text{Ba}_3\text{N}_2$: Elements - Barium (Ba), Nitrogen (N); Atom counts - Ba: 3, N: 2
3. $\text{C}_6\text{H}_{12}\text{O}_6$: Elements - Carbon (C), Hydrogen (H), Oxygen (O); Atom counts - C: 6, H: 12, O: 6
4. $\text{BaCl}_2$: Elements - Barium (Ba), Chlorine (Cl); Atom counts - Ba: 1, Cl: 2
5. $\text{CH}_4$: Elements - Carbon (C), Hydrogen (H); Atom counts - C: 1, H: 4
6. $\text{Pb(NO}_3\text{)}_2$: Elements - Lead (Pb), Nitrogen (N), Oxygen (O); Atom counts - Pb: 1, N: 2, O: 6
7. $\text{(NH}_4\text{)}_2\text{S}$: Elements - Nitrogen (N), Hydrogen (H), Sulfur (S); Atom counts - N: 2, H: 8, S: 1
8. $\text{Cr(C}_2\text{H}_3\text{O}_2\text{)}_2$: Elements - Chromium (Cr), Carbon (C), Hydrogen (H), Oxygen (O); Atom counts - Cr: 1, C: 4, H: 6, O: 4
9. $\text{Mg}_3\text{(PO}_4\text{)}_2$: Elements - Magnesium (Mg), Phosphorus (P), Oxygen (O); Atom counts - Mg: 3, P: 2, O: 8
10. $\text{CH}_3\text{COOH}$: Elements - Carbon (C), Hydrogen (H), Oxygen (O); Atom counts - C: 2, H: 4, O: 2