chemistry help .. i don't understand this. plz help me thank you?

Question

i really don't get this plz help me i have a test tommorow but still not getting the molar ratio works..

9. The elements lithium and oxygen react ex-
plosively to from lithium oxide (Li2O). How much lithium oxide will form if 2:6 mol of
lithium react? Answer in units of mol.


10. Ammonia (NH3) is widely used as a fertilizer
and in many household cleaners. How much
ammonia is produced when 5:39 mol of hydro-
gen gas react with an excess of nitrogen gas?
Answer in units of mol.

11. How many atoms are in 2 x10^-10 g Au



4. In 0:29 mol of SO2 there are how many moles
of oxygen atoms? Answer in units of mol.

Answer 1

Didnt get you correctly is it2:6 or 2.6 mol
anyways
9. 4Li + O2 ---->2LiO2
Thus 1 mol Li gives 0.5 mol Li2O
2.6 mol Li gives 1.3 mol Li2O

10. Since Hydrogen is limited it decides the amount of ammonia formed.
3H2+ N2----->2NH3
3 moles of hydrogen gives 2 moles of ammonia.
5.39 moles of hydrogen gives 2*5.39/3 moles of ammonia = 3.593 moles of Ammonia.

11. Atomic weight of gold =197
thus 197 g gold contains 6.0225*10^23 atoms
thus 2 x10^-10 g Au contains 6.0225*10^23 *2 x10^-10/197= 6.1138 * 10^11 atoms.

4. 1 mol SO2==2 mol O atoms
0.29 mol SO2==0.58 mol O atoms