How many molecules are there in 150g of nano3?
3. how many grams are there in 5.7 * 10^46 molecules of nano3?
4. how many grams are there in 301 miles of water, h2o?
5. how many miles are there in 25g of h2so4?
6. how many molecules are there in 252g of ca(oh)2?
7. how many grams are there in 6.7 * 10^35 atoms of calcium? if you answer this could you put each step too

For the whole set of problems, always remember the Avogadro’s number is 6.023*10^23 units per mole of a substance. Units could be atoms, molecules or formula units.  
The first question asks for the number of molecules of NaNO3. The molar mass of NaNO3 is 85 grams per mole. So,
150g NaNO3(1mole NaNO3/85 grams NaNO3)(6.023*10^23 molecules/1mole NaNO3)=1.063*10^24 molecules of NaNO3  

5.7*10^46 molecules of NaNO3(1mole NaNO3/6.023*10^23 molecules)(85 grams NaNO3/1mole NaNO3) = 8.044*10^24 grams NaNO3  

For the molar mass of water, we have 18.02grams per mole.
301 moles H2O(18.02 grams H2O/1 mole H2O) = 5424.02 grams H2O  

For the molar mass of sulfuric acid, we have 98.08 grams per mole.  
25g H2SO4(I mole H2SO4/98.08g H2SO4) = 0.2549 mole H2SO4  

For the molar mass of Ca(OH)2, we have 74.1 grams per mole.
252gCa(OH)2(1mol/74.1g)(6.023*10^23/1mol) = 2.048*10^24 molecules of Ca(OH)2  

For the molar mass of calcium, we have 40 grams of Ca per mole.
6.7*10^35 atoms Ca(1 mole Ca/6.023*10^23 atoms)(40g Ca/1mol Ca) = 4.45*10^13 grams Ca

The correct name for n3-ion should be azide.