Question

A chemist mixes 108 g of H2O, with 186 L of NO2 at STP. How many grams of NO will be produced? The balanced equation for this reaction is:

H2O + 3 NO2  2 HNO3 + NO

Answer 1

change both values to moles
H2O
mass is given
so use the formula
mole = mass/ molecular mass
u can calculate the molecular mass using periodic table
and so get the answer for mole of H2O

Answer 2

next, you are given volume of NO2 & you are given the condition STP
so use formula
Volume = mole x STPvolume
so make mold as subject since we need mole
mole = Volume / STPvolume
Volumd = ur given volume
STPvolume = 22.4 L
so put the values into the formula and get your mole for NO2

Answer 3

now you have both moles
compare them
the ratio is
H2O : NO2
1 : 3

so compare the values u got
see which is less and which is more accordingly with the ratio between them
then u can see which value is bigger or less
the value that is less = limiting reactant
the value that is more = excess reactant

Answer 4

once u find limiting reactant use its mole & coefficient and do the ratio between limiting reactant & NO

Answer 5

for example: if NO2 is your limiting reactant
you need to compare it with NO
3 : is the ratio
3 - mole of NO2
1 - mole of NO
so
mole of NO = 3/ mole of NO2
so now find mole of NO

Answer 6

now just use this formula
mole = mass / molecular mass
mass = mole x molecular mass
u know both mole & molecular mass of NO
so put into formula & get the mass in grams

thats about it