Which of the following is a correctly written chemical equation that demonstrates the conservation of mass?


Mg + HC1
→
H
2
+
MgC
1
2
Mg + HC1 → H 2 + MgC 1 2

H
2
O
+
C
O
2
→
H
2
C
O
3
H 2 O + C O 2 → H 2 C O 3

KC
1
O
3
→
KC1 +
O
2
KC 1 O 3 → KC1 + O 2

H
2
+
O
2
→
H
2
O
H 2 + O 2 → H 2 O