Write and balance the 5 reactions?

The only way that you will learn to write and balance equations is by doing them over and over again. The basic steps are quite easy for most reactions. The initial difficulty is often learning names and formulas, but again with practice this becomes quite easy to do. I'll walk through a couple of these and you can do the rest.

b) Here, the formula of ammonia is given to you, and you know that oxygen is O2, nitrogen is N2 and water is H2O. So you start with:
NH3 + O2 --> N2 + H2O
Since you have N2 on the right, you must have 2 NH3 on the left:
2 NH3 + O2 --> N2 + H2O
That gives you 6 H on the left, so you need 3 H2O on the right:
2 NH3 + O2 --> N2 + 3 H2O
Now, you have 3 O on the right, so you need 3 O on the left, but you have O2 on the left. You could write 3/2 O2, and this is not necessarily wrong. But generally we want to use whole number coefficients. So, you need to multiply everything by 2. That gives you the final balanced equation:
4 NH3 + 3 O2 --> 2 N2 + 6 H2O

c) is really straightforward

d) The unbalanced equation is:
P4O10 + H2O --> H3PO4
Since you have 4 P on the left, start with 4 H3PO4 on the right
P4O10 + H2O --> 4 H3PO4
Since you now have 12 H on the right, start with 6 H2O on the left:
P4O10 + 6 H2O --> 4 H3PO4
Now, you have 16 O on the left and 16 O on the right, so it is balanced.

e) Unbalanced equation is:
BaCl2 + K3PO4 --> Ba3(PO4)2 + KCl
You should be able to balance this one....

a)
Aluminum reacts with hydrogen chloride to yield aluminum chloride and hydrogen gas
2Al + 6HCl → 2AlCl₃ + 3H₂

b)
Ammonia (NH3) reacts with oxygen to yield nitrogen gas and water
4NH₃ + 3O₂ → 2N₂ + 6H₂O

c)
Sodium metal reacts with chlorine gas to form sodium chloride
2Na + Cl₂ → 2NaCl

d)
Tetraphosphorous decaoxide reacts with water to yield hydrogen phosphate (H3PO4)
P₄O₁₀ + 6H₂O → 4H₃PO₄

e)
Barium chloride reacts with potassium phosphate to yield barium phosphate and potassium chloride
3BaCl₂ + 2K₃PO₄ → Ba₃(PO₄)₂ + 6KC