Hi, I have some reviw questions for the upcomming chemistry exam, the problem is I don't have the answers so can some one read throught my work and check if it is wright? Thanks. *** 1. An anaysis of a valitile liquid shoed that it wsa composed of 14.4%C, 2.37% H and 83.49% Cl. If 4.25 g of the liquid was vaporized and occupied 628 mL at 65 degrees celcuios and 112 kpa, what would be the molecular formula of the compund? carbon 14.4% x 100g = 14.4 g m=14.4 g n=1.199 mol Mm=12.01 g/mol hydrogen 2.37% x 100g =2.37g m=2.37 g n=2.347mol Mm=1.01 g/mol Cholrine 83.49% x 100g =83.49g m=83.49 g n=2.355mol Mm=35.45 g/mol so... 1.199 / 1.199 =1 2.37 / 1.1.99=2 2.355/ 1.199=2 Impirical Formula C1 H2 Cl2 # mol of Impirical formula PV=nrt n=PV/rt n=(112Kpa)(0.628L)/ 8.314kpaL/molL (388k) n=0.025 mol Molar mass of Impreical formula Mm=m/n Mm=4.25g/0.025 mol Mm=170 g/mol Molar mass of ( what is this the molar mass of???) C1 H2 Cl2 84.93 Find a Factor 170g/mol/ 84.93 g/mol =2 Molecular Formula 2(C1 H2 Cl2) C2 H4 Cl4 *** 2. A gas has a volume of 40.0 ml at 40 degrees celcuios and 95 Kpa. What will be its volume at STP? gas 40.0 mL = 0.04L 40 degrees celcioue=313 K 95 kPa=P n=rt/pv n= 8.134(313)/95(0.04) n=27.3890 mol v=nrt v=27.3809(8.134)(273)/101.3 v=613.4948 *** 3. How many grams of sodium and required to product 2.24 L of Hydrogen gas, measured at 25 degrees celcuoiu adn 110 Kpa, according to the following reaction? 2Na + 2 H2O ---> 2 NaOH + H2O n=rt/pv n= 8.314(298)/110(2.24) n=10.055 m=nMm m=20.11 (22.99) m=462.3289 B)calculate the volume of H2(g) produced when 54 g of Na(s) reacts with an excess of water at STP. moles of Na n=m/Mm n=54/22.99 n=2.348 moles H 3.348/2 1.174 Volume v=nrt/p 1.174(8.314)(273)/101.3 v=2.791 *** 4. An aquois solution has a volume of 2.0L and contains 36.0 g of glucose. If the molar mass of glucose is 180 g , what is the molarity of the solution? molar mass of glucose n=m/Mm n=36.0/180 n=0.2 ...what next? *** 5. How would you prepare 100ml of 0.40 mol/L MgSO4 form a stock solution of 2.0 mol/L MgSO4? n=0.100L/0.40 mol/L 0.25 v=n/c v=0.25/2.0 v=0.125L add 0.125L of MgSO4 *** 6. A solution contains 5.85 g of sodium chlride dissolved in 5.00 x 10^3 ml of water. What is the concentration of the sodium cholirde solution? n=M/Mm n=0.0568 mol C=n/v 0.0568/5 =0.01136 mol/L *** 7.what mass of potassium hydroxide is required to prepare 6.00 x 10^2 ml of a solution with a concentration of 0.225 mol/L m=cv 0.225(0.5) 0.135mol *** 8. What volume of 0.500mol/L sodium hyroxide solution can be prepared form 10.0 ml of a 6.00 mol/L solution? C1V1=C2V2 6(0.01)=0.500(v2) 0.12=v2 *** 9. What is the mass of hydrochoric acid that is present in 500 mL of a solution containg 3.50 mol/L of HCl(aq)? n=cv 3.50(0.5) =1.75 mol m=nMm 1.75(36.46) 63.805g *** 10. Passing a park throught a mixture of hydrogen gas and oxygen gas produced water a) calculate the mas of hydrogen needed to completly convert 4.00 g of oxygen into water H2 + O = H2O moles of O n=m/Mm 4.00/18.025 0.22 moles of H 0.22 mol mass of H m=nMm =0.22(1.01) =0.224 b) calcute the number of moles of oxygen required to react with 12.5 moles of hydrogen gas I dont know how to do this one c)calculate the number of moles of water produced when 4.00 g of oxygen are used I dont know how to do this one *** Thanks for reading pleas post any corrections and solutions to the problems I don't know how to do. this is practise for an exam so pleas help!!!!