20. mol H2 reacts with 8.0 mol O2 to produce H2O. Determine the number of grams reactant in excess and number of grams H2O produced. Identify the limiting reactant. 8.1 g H2 , 2.9 x 102 g H2O 17. How many litres of O2 gas are required to produce 100. g Al2O3?
CHEM 1412 SAMPLE FINAL EXAM PART I - Multiple Choice (2 points each) _____ 1. In which colligative property(ies) does the value decrease as more solute is added? A. boiling point B. freezing point and osmotic pressure C. vapor pressure D. freezing point and vapor pressure _____ 2. What is the molarity of a solution prepared by dissolving 25.2 g of CaCO3 in 600 mL of solution? A.
There will have some error. 2) A volatile liquid was allowed to evaporate in a 43.298 g flask that has a total volume of 252 ml. the temperature of the water bath was 100˚C at the atmospheric pressure of 776 torr. The mass of the flask and condensed vapor was 44.173 g. calculate the molar mass of the liquid. T = 273 + 100 = 373 V = 252 mL = 1 L / 1000 mL = 0.252 L P = 776 Torr R= 0.0821 mass of 44.173 - 43.298 g = 0.875g moles of gas = PV / RT = 776 x .252 / 62.363 x (273+100) =0.00841 moles molar mass = 0.875g / 0.00841 moles = 104.1 g/
Lab 4: Determination of Percent by Mass of the Composition in a Mixture by Gravimetric Analysis Introduction Thermal gravimetric analysis is used to determine the percent by mass is used to determine the percent by mass of a component in a mixture. When a mixture is heated to an appropriately high temperature, one component in the mixture decomposes to form a gaseous compound. The mass of this particular component is related to the mass of the gaseous compound. In this experiment, the percent by mass of sodium hydrogen carbonate (NaHCO3) and potassium chloride (KCl) in a mixture will be determined. Experimental First, we weighed 2 samples, each has 1 gram of NaHCO3-KCl mixture Second, we put the samples in 2 crucibles (A and B) and weighed them.
pyridinium hydrobromide perbromide type of stationary phase column length column temperature rate ﬂow of the carrier gas List the 4 general factors that affect the separation obtained on a gas chromatograph What speciﬁc technique is used to collect/isolate your puriﬁed unknown compound at the end of the recrystallization experiment? suction ﬁltration 14 of 22 4/16/12 9:15 PM StudyBlue Flashcard Printing of Lab Final 2211L UGA
3 x (C H5 N) = C3H15N3 Hydrated compounds Solving process: 1st- the difference between the initial mass and that of the dry sample is the mass of water that was driven off. Mass of hydrate minus mass of dry sample equals the mass of water 10.407 – 9.520 = 0.887 g 2nd- The mass of dry BaI2 and the mass of water are converted to MOLES. 9.520 g BaI2 x 1 mol BaI2 ∕ 391 g BaI2 = 0.0243 mol BaI2 anhydrate 0.887 g H2O x 1 mol H2O / 18.0 g H2O = o.o493 mol H2O 3rd: Dividing both results by the amt of 0.0243 mol, we get a ratio of 1 to 2.03, or 1 to 2, since the formula must have full numerical integers of water molecules, in other words no fractions of a water molecule. Thus, for every 1 mole of BaI2, there are two moles of water. The formula for the hydrate is written as BaI2 • 2H2O And it is named barium iodide dihydrate.
The reaction that occurred with this step was displacement and metathesis in the form of gas formation. The balanced equation of this step looks as follows: CuSO4aq+Zns→Cus+ZnSO4(aq) Once this step was finished, the remaining copper was retrieved. First, to recover the copper HCl was added to remove all the zinc. When this happened, a yellow tint was observed in the liquid, as well as bubbling as the zinc was broken down. Once the copper dried out, it was weighed and came to a total of 240 mg.
Conclusion 10 Grams of Potassium chlorate when decomposed produces 3.915576 grams oxygen gas and 6.083363 grams potassium chloride Atomic Weight of Magnesium Introduction In this lab we will determine the atomic weight of magnesium by measuring the amount of hydrogen gas evolved when hydrochloric acid reacts with magnesium. The reaction is as follows: Mg + 2HCl -> H2 + Mg2+ (aq) + 2Cl- (aq) There is a one to one relationship between the number of moles of hydrogen gas evolved and the
If 0.100 mol of hydrogen iodide is placed in a 1.0 L container and allowed to reach equilibrium, find the concentrations of all reactants and products at equilibrium. 2 HI (g) === H2 (g) + I2 (g) Ke = 1.84(10-2 [H2]=[I2]= 1.07(10-2 mol/L, [HI]=7.86(10-2 mol/L 6. A 1.00 L reaction vessel initially contains 9.28(10-3 moles of H2S. At equilibrium, the concentration of H2S of 7.06(10-3 mol/L. Calculate the value of Ke for this system.
For zinc ion to react, the NaEDTA must also be an ion in the solution which means that the large salt must be dissolved in water. Procedure 1) Weighed out 3.64 of NaEDTA on an electronic beam balance 2) Added this mass of NaEDTA using wide mouth funnel to a 250 mL volumetric flask. 3) Rinsed the funnel with a squirt bottle containing deionized water making sure none of the solid remained in the funnel. 4) Added about 100-200 mL of deionized water to the volumetric flask containing the solid NaEDTA. 5) Swirled the solution until the NaEDTA (s) dissolved entirely.