Question

1. choose the best answer. which chemical equation demonstrates the law of conservation of mass? \\( 3h_2o_2 \

ightarrow 3h_2o + o_2 \\) \\( nh_3 \
ightarrow n_2 + 3h_2 \\) \\( p_4 + 3na \
ightarrow na_3p \\) \\( h_2so_4 \
ightarrow h_2o_2 + so_2 \\) 4) choose the best answer. which reaction between phosphorus trihydride and oxygen follows the law of conservation of mass? \\( 4ph_3 + o_2 \
ightarrow p_4h_{10} + 2h_2o \\) \\( 8ph_3 + 2o_2 \
ightarrow 2p_4h_{10} + 2h_2o \\) \\( 8ph_3 + o_2 \
ightarrow 2p_4h_{10} + 2h_2o \\) \\( 4ph_3 + o_2 \
ightarrow p_4h_{10} + 6h_2o \\)

Explanation:

Step1: Check Q3 eq1 atom count

Left: H=6, O=6; Right: H=6, O=5. Not balanced.

Step2: Check Q3 eq2 atom count

Left: N=1, H=3; Right: N=2, H=6. Not balanced.

Step3: Check Q3 eq3 atom count

Left: P=4, Na=3; Right: P=1, Na=3. Not balanced.

Step4: Check Q3 eq4 atom count

Left: H=2, S=1, O=4; Right: H=2, S=1, O=4. Balanced.

Step5: Check Q4 eq1 atom count

Left: P=4, H=12, O=2; Right: P=4, H=12, O=2. Balanced.

Step6: Check Q4 eq2 atom count

Left: P=8, H=24, O=4; Right: P=8, H=24, O=2. Not balanced.

Step7: Check Q4 eq3 atom count

Left: P=8, H=24, O=2; Right: P=8, H=24, O=2. Balanced, but stoichiometry is not the simplest valid ratio for this reaction.

Step8: Check Q4 eq4 atom count

Left: P=4, H=12, O=2; Right: P=4, H=22, O=6. Not balanced.

Answer:

1. $\boldsymbol{H_2SO_4

ightarrow H_2O_2 + SO_2}$

1. $\boldsymbol{4PH_3 + O_2

ightarrow P_4H_{10} + 2H_2O}$