Answer:
The answer is 15 units.
Step-by-step explanation:
The reason it is 15 units is because We know that QV = 15 and TQ = TS, QV = SV;4 x - 1 = 154 x = 15 + 14 x = 16x = 16 : 4 = 4 henceforth the answer being 15 units
So, here you have to look at the periodic table and see what the molar mass of each molecule composing the water compound

its two hydrogen atom plus an oxygen molecule, making it about 18g per mol.
That said, looking at the mass, we have to ask ourselves, if a mol of water contains 18g of mass, how many moles do we have in 0.5g of water?
We just do a cross multiplication:
Answer:
315
Step-by-step explanation:
1. This is not a scale rectangle and it angers me.
2. All you have to do is draw proportions.
5x7=35
15x21=315
Youll notice that 5x3=15 and 7x3=21 so it’s just proportions!