Question

1- What is the percent composition of 5-phosphomevalunate (C₆H₁₀PO₇), a biochemical messenger? Consider Significant Figures

%C =

%H =

%P =

%O =

2- What is the percent yield for a reaction where 32.50g of Cu should be made and 27.48g Cu is recovered? Consider Significant Figures

3- Waste calcium sulfate can be removed from plaster in the following sequence of steps. What volume in L of 0.1250M calcium hydroxide solution can be prepared from 138.2g calcium sulfate? Consider Sig Fig

CaSO_4(s) + 4C _(s)  à CaS_(l) + 4CO_(g)

CaS_(l) + 3CaSO_4(s)  à  4CaO_(s) + 4SO_2(g)

CaO_(s) + H₂O_(l)  à Ca(OH)_2(aq)

4- If 645.0ml of 0.235M gallium III chromate is used to react with 148.46g silver nitrate, what mass in g of silver chromate should be produced?

Consider Sig Figs

5- Butyric acid is a naturally occurring hydrocarbon found in rancid butter. A sample of butyric acid is analyzed and found to contain 52.1% C, 8.77% H, and 34.7% O. Further research shows the formula mass of butyric acid to be 88.12g/mol. Determine the empirical formula and molecular formula of of butyric acid. Consider Sig Fig

Answer 1

Molecular weight of this compound is

12x6 + 10x 1 + 30.97 x1 + 15.98 x 7

= 72 + 10+ 30.97 + 111.86 = 224.83 gm per mol

%C = (72/224.83)x100 = 32.024 %

%H = (10/224.83)x100 = 4.447 %

%P = (30.97/224.83)x100 = 13.774%

%O = (111.86/224.83)x100 = 49.753%

These are the % C, H, P and Oxygen .