To find the mass percent of dolomite [CaMg(CO3)2] in a soil sample, a geochemist titrates 11.30 g of soil with 35.90 mL of 0.2516 M HCl. What is the mass percent of dolomite in the soil?
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2007-10-08 05:21:12 · 2 answers · asked by bumblebee 4 in Science & Mathematics ➔ Chemistry
From titration,
35.90mL x .2516M = 9.032mmol
so, there are 0.009032 moles of dolomite in 11.3g of soil
the molar mass = 11.3/0.009032
= 1251.05 g/mol
molar mass of dolomite = 184.4 g/mol
% of dolomite in soil = 184.4/1251.05 x 100%
= 14.74%
2007-10-08 05:49:09 · answer #1 · answered by nosha47 3 · 0⤊ 0⤋
REMEMBER: YOU HAVE TO CONVERT TO MOLES TO DO THESE PROBLEMS.
Find the moles of HCl (0.0359L*0.2516Molar)= M1
Check reaction for conversion from HCl to dolomite
CaMg(CO3)2 + 4 HCl = CaCl2+MgCl2+"2H2CO3"
Number of moles of dolomite reacting with HCl = M1/4
Mass of dolomite in soil= molwt dolomite*M1/t
Percent dolomite in soil= mass dolomite*100/soil wt.
2007-10-08 05:28:49 · answer #2 · answered by cattbarf 7 · 0⤊ 0⤋