Answer:
First we know that the molar mass of CO2 is 44.01g/mol, and that the sample of CO2 contains 3.408 x 10^21 molecules, and we have to find the mass of that sample.
We know that moles = mass/molar mass, if we rearrange the equation for mass, we'll get:
mass = moles x molar mass
Also, note that the number of atoms/molecules in a sample is the moles of the sample x Avogadro's number (6.02 x 10^23)
If we rearrange the equation for moles, we would get:
moles = molecules of sample/6.02 x 10^23
Plug in the values for the equation above to get the moles:
moles = (3.408 x 10^21)/(6.02 x 10^23)
moles = 0.00566112956 (we're not done yet)
Now that we have the moles and we were already provided the molar mass, we can calculate the mass using the very first equation we rearranged.
mass = moles x molar mass
mass = 0.00566112956 x 44.01
mass = 0.2491g (answered 4 places past the decimal point)
Therefore the sample of Carbon Dioxide has a mass of 0.2491g
