Can you check my answers for some chemistry questions? Can you correct the ones I get wrong?

Question

6. Silver will dissolve in concentrated nitric acid, producing NO gas and leaving a solution of silver nitrate in water. Write the UNBALANCED chemical equation for this process.

A. Ag (s) + HNO3 (aq) --------> NO (g) + AgNO3 (aq)

7. Calcium carbonate reacts by combining with hydrochloric acid, producing a solution of calcium chloride, converting the acid into water, and releasing carbon dioxide gas. Write the UNBALANCED chemical equation for this process.

A. CaCO3 (g) + HCl (aq) --------> CaCl2 (aq) + CO2

8. Hydrogen sulfide burns in air, producing sulfur dioxide gas and water vapor. Write the UNBALANCED chemical equation for this process.

A. H2S (g) --------> SO2 (g) + H2O (g)

9. The group 2 metals (Ba, C, Sr) can be produced in elemental state by the reaction of their oxides with aluminum metal at high temperatures, also producing solid aluminum oxide as a by-product. Write the UNBALANCED equation for the formation of ozone gas from oxygen gas.

A. What?

Answer 1

6. Ag (s) + HNO3 (aq) --------> NO (g) + AgNO3 (aq) + H2O

7. CaCO3 (s) + HCl (aq) --------> CaCl2 (aq) + CO2 + H2O
Calcium carbonate is usually a solid.

9. Oxides are basically compounds with oxygen in it (e.g.: BaO, NO)
BaO + Al --> Ba + Al2O3
CaO + Al --> Ca + Al2O3
SrO + Al --> Sr + Al2O3

Answer 2

For #6: you forgot the water that is also produced (that's where the hydrogens go that were on the nitric acid)

Ag + HNO3 ---> NO + H2O + AgNO3 (un-balanced)

For # 7 you also forgot the water that is produced:

CaCO3 + HCl ---> CaCl2 + CO2 + H2O (un-balanced)

#8 is OK.

For the last one, it would be (un-balanced):

BaO + Al ---> Ba + Al2O3

Ca or Sr can be substituted for Ba in the above equation, they are all similar.