How many grams of S are needed to react with 25.5g of Co?

2 CO + O2 ———————-> 2 CO2

Mass of CO = 174 g

First change it into moles

No of moles = (mass in grams)/molar mass

Molar mass of CO = 30 g/mol

No of moles of CO = 174/30 = 5.8 mol

2 CO + O2 ———————-> 2 CO2

Equation shows that

2 moles of CO react with moles of O2 = 1 mol

1 mole of CO react with moles of O2 = 1/2

1 mole of CO react with moles of O2 = 0.5 mol

5.8 mole of CO react with moles of O2 =0.5x5.8

5.8 mole of CO react with moles of O2 = 2.9 mol

No of moles of O2 used = 2.9 mol

Then change it into no of molecules

No of molecules of O2 = 2.9x6.02x10^23

No of molecules of O2 used = 17.45x10^23

Explanation:

i do not get it   at all

the answer is d. 74.02