Which sample of gas contains the FEWEST molecules?

#1.# #"A 4.4 g mass of carbon dioxide."#
#2.# #"A 3.4 g mass of ammonia."#
#3.# #"A 1.6 g mass of methane."#
#4.# #"A 3.2 g mass of sulfur dioxide."#

1 Answer
May 24, 2017

Answer:

#"Sample 4"#, #"sulfur dioxide."#

Explanation:

All we need to do is to calculate the molar quantity of each gas, and we know that #1*mol# of any substance constitutes #6.022xx10^23# individual particles of that substance.........

#"Moles of"# #CO_2=(4.4*g)/(44.01*g*mol^-1)=0.1*mol#.

#"Moles of"# #NH_3=(3.4*g)/(17.01*g*mol^-1)=0.2*mol#.

#"Moles of"# #CH_4=(1.6*g)/(16.04*g*mol^-1)=0.1*mol#.

#"Moles of"# #SO_2=(3.2*g)/(64.1*g*mol^-1)=0.05*mol#.

Since the molar quantity represents an actual number, #N_A=6.022xx10^23*mol^-1#, clearly, there are FEWER #"sulfur dioxide"# molecules than the number of molecules of any other gas. In other words, since #SO_2(g)# is the heaviest, the given mass contains the least number of molecules.