# WAEC GCE Chemistry Essay Answers Live

on September 16, 2015

(1a)
(i)
Mass concentration of
B=3.95/750*1000
=5.2g/dm
VA=22.70cm^3 VB=25.0cm^3
(ii)
Concentration of B in mol/dm^3
=Concentration in g/dm^3/Molar mass
in g/mol
Molar mass of Na2CO3
=(23*2)+(12)+(16*3) =46+12+48
=106g/mol
Concentration in mol/dm^3=5.27/106
=0.0497mol/dm^3
(iii)
CAVA/CBVB=nA/nB
(CA*22.70)/(0.0497*25)=1/1
CA=(0.0497*25*1)/22.70*1)
CA=0.0548mol/dm^3
(iv)
CA=concentration in g/dm/molar mass
Molar mass of A=H2SO4
=(1*2)+32+(16*4)
=2+32+64
=98g/mol 0.0548=concentration in g/dm^3/98
Concentration of A in g/
dm^3=0.0548*98
=5.37g/dm^3 ### About the Author (Author Profile)

myPastQuestion.com is the largest past question database for all types examination in Nigeria. We have Post UTME Past Questions for all Universities, Polytechnics and Colleges of Education. We also have CBT Software, Scholarships Past Questions, WAEC and NECO Past Questions. Follow Ifiokobong Twitter and share what you love most.

1. Kelly says: