Question

Which of the following samples contains the greatest number of atoms?

a. 9 mole of CO2 b. 10 moles of Xe
c. 11 moles of N2O d. 12 moles of CO

Answer 1

c. 11 moles of N2O.

Step-by-step explanation:

Hello,

In this case, for each substance, we use the Avogadro's number to compute the number of atoms in the given sample:

a.

`atoms \ C=9molCO_2*(1molC)/(1molCO_2) *(6.022x10^(23)atoms\ C)/(1molC) =5.4x10^(24)atoms\ C`

`atoms \ O=9molCO_2*(2molO)/(1molCO_2) *(6.022x10^(23)atoms\ O)/(1molO) =1.1x10^(25)atoms\ O`

`Total\ atoms=1.1x10^(25)+5.4x10^(24)=1.64x10^(25)atoms`

b.

`atoms \ Xe=10molXe *(6.022x10^(23)atoms\ Xe)/(1molXe) =6.022x10^(24)atoms`

c.

`atoms \ N=11molN_2O*(2molN)/(1molN_2O) *(6.022x10^(23)atoms\ N)/(1molN) =1.3x10^(25)atoms\ N`

`atoms \ O=11molN_2O*(1molO)/(1molN_2O) *(6.022x10^(23)atoms\ O)/(1molO) =6.6x10^(24)atoms\ O`

`Total\ atoms=1.3x10^(25)+6.6x10^(24)=2.0x10^(25)atoms`

d.

`atoms \ C=12molCO_2*(1molC)/(1molCO_2) *(6.022x10^(23)atoms\ C)/(1molC) =7.2x10^(24)atoms\ C`

`atoms \ O=12molCO_2*(1molO)/(1molCO_2) *(6.022x10^(23)atoms\ O)/(1molO) =7.2x10^(24)atoms\ O`

`Total\ atoms=7.2x10^(24)+7.2x10^(24)=1.44x10^(25)atoms`

Thus, we notice 11 moles of N2O have the greatest number of atoms.

Best regards.

Answer 2

12 moles of CO

Step-by-step explanation:

According to Avogadro, one mole of a substance, contains the same number of elementary entities as 12g of carbon-12. Now the number of elementary entities (atoms, molecules, ions, particles etc) in any substance is given by the Avogadro's constant.

Now since 1 mole of a substance contains Avogadro's number of atoms, it means that the substance with the highest number of moles will have the highest number of atoms.

With this in mind we can see that 12 moles of CO is expected to contain 72.24 ×10^23 atoms of CO. Hence the answer.