How many atoms are in a #92.0*g# mass of ethyl alcohol?

2 Answers
Jan 28, 2018

Well, ethanol has a molar mass of #46.07*g*mol^-1#....and there are #6xxH+1xxO+2xxC="9 atoms per EtOH molecule"#

Explanation:

And thus we have a molar quantity of #(92*g)/(46.07*g*mol^-1)~=2.0*mol#

And it is a fact that one mole of stuff contains #6.022xx10^23# individual molecules....and so we have approx...

#2*molxx6.022xx10^23*mol^-1xx9*"atoms"#

#~=18*N_A# atoms, where #N_A-="Avocado number...."#

Jan 28, 2018

#~~2.0xx N_A" atoms " C_2H_5OH#

Explanation:

  1. Ethanol is a simple alcohol also called ethyl alcohol with a chemical formula of #C_2H_5OH#. Its molar mass #(Mm)# is obtainable from the periodic table.

    #MmC_2H_5OH=(46.07g)/(mol)#

  2. Given its mass, the mole relationship that 1mol of any substance is equivalent to #6.02xx10^23 (N_A)# number of atoms of that substance for the required molar conversionded ; i.e.,

    #1molC_2H_5OH-=6.02xx10^23 " atoms "C_2H_5OH #

  3. Conversion processes are shown below.

From mass to mole:

#=92gcancel(C_2H_5OH)xx(1molC_2H_5OH)/(46.07cancel(gC_2H_5OH))#
#~~2.0molC_2H_5OH#

From mole to number of atoms:
#=2.0molC_2H_5OHxx(6.02xx10^23 " atoms " C_2H_5OH)/(1molC_2H_5OH)#
#=12.04xx10^23" atoms " C_2H_5OH#
#=1.2xx10^24" atoms " C_2H_5OH#