Let's compare the total mass of the reactants to the total mass of the products for each chemical reaction provided:
### Option A:
Reactants:
[tex]\[ 32 \, \text{g} \, CH_3OH + 38 \, \text{g} \, O_2 = 70 \, \text{g} \][/tex]
Products:
[tex]\[ 44 \, \text{g} \, CO_2 + 18 \, \text{g} \, H_2O = 62 \, \text{g} \][/tex]
Difference:
[tex]\[ 70 \, \text{g} - 62 \, \text{g} = 8 \, \text{g} \][/tex]
### Option B:
Reactants:
[tex]\[ 28 \, \text{g} \, N_2 + 6 \, \text{g} \, H_2 = 34 \, \text{g} \][/tex]
Products:
[tex]\[ 24 \, \text{g} \, NH_3 \][/tex]
Difference:
[tex]\[ 34 \, \text{g} - 24 \, \text{g} = 10 \, \text{g} \][/tex]
### Option C:
Reactants:
[tex]\[ 29 \, \text{g} \, K + 18 \, \text{g} \, H_2O = 47 \, \text{g} \][/tex]
Products:
[tex]\[ 56 \, \text{g} \, KOH + 10 \, \text{g} \, H_2 = 66 \, \text{g} \][/tex]
Difference:
[tex]\[ 47 \, \text{g} - 66 \, \text{g} = -19 \, \text{g} \][/tex]
### Option D:
Reactants:
[tex]\[ 12 \, \text{g} \, C + 32 \, \text{g} \, O_2 = 44 \, \text{g} \][/tex]
Products:
[tex]\[ 44 \, \text{g} \, CO_2 \][/tex]
Difference:
[tex]\[ 44 \, \text{g} - 44 \, \text{g} = 0 \, \text{g} \][/tex]
### Conclusion:
The Law of Conservation of Mass states that the total mass of the reactants must equal the total mass of the products. From the differences calculated:
- Option A has a mass difference of 8 g.
- Option B has a mass difference of 10 g.
- Option C has a mass difference of -19 g.
- Option D has a mass difference of 0 g.
Thus, Option D [tex]\(12 \, \text{g} \, C + 32 \, \text{g} \, O_2 \rightarrow 44 \, \text{g} \, CO_2\)[/tex] demonstrates the Law of Conservation of Mass because the total mass of reactants equals the total mass of products.
