Question #ccb14

1 Answer
Oct 31, 2015

Answer:

#0,1833mol#.
#1,104xx10^23# particles.
#71,11%# oxygen by mass.

Explanation:

Moles = Mass divided by molar mass.
#therefore n=(16,5g)/(2xx1+12xx2+16xx4g//mol)=0,1833mol#

One mole contains an Avagadro number of particles, ie #6,023xx10^23# particles.
Hence by ratio and proportion, 0,1833 moles will contain
#0,1833xx6,023xx10^23=1,104xx10^23# particles.

In 1 mole of #H_2C_2O_4#, which has a mass of 90g, exactly 64g of this 90g is oxygen. this corresponds to a percent of #64/90xx100=71,11%#.