To do this you need to work out formula mass, the weight of 1 mole of any chemical.
Waters formula is H2O so write;
2H
O
Then find the relative Atomic Mass of these elements
Hydrogens weigh is 1
Oxygen is 16
2x1
1x16
then add them together
2+16 = 18
that is the weight in grams of 1mole
so 36g is the weight of 2moles
75 grams water is equal to 4,166 moles.
0.377 grams of Kr is equal to 0,0045 moles.
124 grams of ethane is equal to 4,124 moles.
54,0 grams of water is equivalent to 3 moles.
15 grams of nitrogen are equal to 1,071 moles.
75 grams water is equal to 4,166 moles.
3.65 grams of water is equal to .203 moles of H2O. This means there is also .203 moles of H2 present, or .408 grams.
180 grams of water is 10 moles of water.
0.377 grams of Kr is equal to 0,0045 moles.
124 grams of ethane is equal to 4,124 moles.
370 grams of mercury is equal to 1,844 moles.
54,0 grams of water is equivalent to 3 moles.
1,99 grams of aluminum is equal to 0,0737 moles.
15 grams of nitrogen are equal to 1,071 moles.
6,5 grams of sulfur S are equal to 0,203 moles.
89 grams of Pb(CH3COO)4 is equal to 0,2 moles.
7,68 grams of calcium nitride is equal to 0,052 moles.