PbO2
You have to take the mass of lead in the problem, and divide by the molar mass.
When you do the same with oxygen, you get a number about twice as large as when you divide the mass of lead by the molar mass of lead. This means that the simplest formula would be PbO2
What's the answer? It asked to be 20 characters long so just writing this.
The value of X is 10 hence the formula of unknown hydrate sodium sulfate is NaSO4.10 H20
calculation
step 1:find the moles of NaSO4 and the moles of H2O
moles= mass/molar mass
moles of Na2SO4=1.42÷142=0.01 moles
moles of H20= mass of H2O/molar mass of H2O
mass of H2O= 3.22-1.42=1.8g
mole of H2O is therefore 1.8÷18=0.1 moles
step 2: find the mole ratio by dividing each mole by smallest number of mole (0.01)
that is Na2So4= 0.01/0.01 =1
H2O= 0.1/0.01=10
<span>Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles. We calculate as follows:
0.180 mol Br2 ( </span>6.022 x 10^23 molecules / mole ) = 1.084x10^23 molecules Br2