To find how many atoms are in the compound, we first have to find how many moles there are. The numbers in the subscript tell you how many moles of each element are present in the compound. Therefore, to find the number of total moles, we can add up each of the numbers in the subscript:
Cu₂Mg₁H₁O₁ *when there is no number under an element, it is implied that there is 1 mole of the element
2+1+1+1=5 moles
We can then use Avogadro's number and dimensional analysis to find how many atoms are in the compound (Avogadro's number is 6.02x10^23):
5 moles (6.02x10^23/1 mole)= 3.01x10^24 atoms
V1/T1=V2/T2
V2=(V1)(T2)/T1
Plug in values given (for the temp you can either turn 300K to 27°C or turn 132°C into kelvin
V2= 4400 mL= 4.4L
Answer is c
Work out the moles of 2H2O: 1.80/ (16+1+1) = 0.1
The moles of 2H2 are the same (0.1)
The Mr of H2 is 2
So the mass needed to produce 1.80g of water is
0.1 x 2 = 0.2
