Chemistry Multiple Choice?

Question

1) Nitrogen and hydrogen combine to form ammonia according to the reaction N_2 + 3H_2 -> 3NH_3
What is the volume of hydrogen required to combine with 2.2L of nitrogen?
a)2.2L
b) 4.4L
c) 6.6L
d) 44.8L

2) The percent by weight of water in calcium chloride dihydrate, CaCl_2·2H_2O, is:
a) 16.1%
b) 12.2%
c) 24.5%
d) 32.4%

3) In an acidic aqueous solution (the square brackets [ ] denote concentrations):
a)[H+] is less than [OH-]
b)[H+] is less than 1 x 10^-14 mol/L
c)[H+] is greater than 1 x 10^-7 mol/L
d)[OH-] is greater than 1 x 10^-7 mol/L

If and where possible could you explain it as well? Please and thank you.

Answer 1

1) c) 6.6 Equal volumes of gases have equal numbers of molecules, and the equation says 3 moles H2 for every 1 of N2.

2) c)

Atomic weights: Ca=40 Cl=35.5 H=1 O=16 H2O=18 CaCl2=111 CaCl2*2H2O=147

36gH2O/147gCaCl2*2H2O x 100% = 24.5%

3) c) [H+] is greater than 1x10^-7, because 1x10^-7 is neutrality for water.

Answer 2

1) c. 6.6L (the mole ratio is 1:3, multiply vol. of nitrogen by 3 to get the vol. of hydrogen)
2)24.5% (RMM=147 RMM of water=36, (36/147)*100)
3) a. P.S. not sure about this answer.