Calculate the no.of moles
(a)3.011 X 10power 23 atoms of He
(b)1.505 X 10power23 of Co2
(c)6.022 X 10power23 atoms of Na (hint :nis equal to N/No)
There are 6.022E23 atoms in a mole of atoms and 6.022E23 molecules in a mole of molecules.
So 3.011E23 atoms x (1 mol/6.022 atoms) = mols He.
b. I don't know. I suspect you made a typo and this is meant to be CO2.
c. This is done the same way as part a. I don't get the hint since you didn't define N/No.
To calculate the number of moles, you can use Avogadro's number and the formula:
Number of moles = Number of particles / Avogadro's number (6.022 x 10^23)
Let's calculate the number of moles for each case:
(a) Number of moles of He atoms:
Number of particles = 3.011 x 10^23
Number of moles = 3.011 x 10^23 / (6.022 x 10^23)
Number of moles = 0.5 moles
Therefore, there are 0.5 moles of He atoms.
(b) Number of moles of CO2 molecules:
Number of particles = 1.505 x 10^23
Number of moles = 1.505 x 10^23 / (6.022 x 10^23)
Number of moles = 0.25 moles (Note that one molecule of CO2 contains one carbon atom and two oxygen atoms.)
Therefore, there are 0.25 moles of CO2 molecules.
(c) Number of moles of Na atoms:
Number of particles = 6.022 x 10^23
Number of moles = 6.022 x 10^23 / (6.022 x 10^23)
Number of moles = 1 mole
Therefore, there is 1 mole of Na atoms.
In general, to calculate the number of moles, divide the number of particles by Avogadro's number.