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?
Empirical formula: CH5N Steps for molecular formula: 1- Calculate the molar mass of the empirical formula. 2- Divide the known (given) molar mass by the calculated empirical formula molar mass to get a whole number 3- Multiply that whole number through subscripts of the empirical formula to obtain the molecular formula. Example CH5N 12.01 g C x 1 C= 12.01 g/mol 1.008 g H x 5 H = 5.040
Determine the percent yield of this reaction, showing all steps of your calculation. (3 points) heoretical yield of H2 gas: (1.156 x 10^-3 moles)(1 mole H2/ 1 mole Mg) = 1.156 x 10^-3 moles Theoretical mass: (1.156 x 10^-3 moles)(2.02 g/mole) = 2.335 x 10^-3 g Using ideal gas law: P = (1.1 atm)(760 torr / 1 atm) - 19.8 torr = 816.2 torr V = 0.026 L T = 295 K Solve for n: n = PV/(RT) n = (816.2 torr)(0.026
What pressure is required to reduce the volume of gases in a car’s cylinder from 48 cm3 at V1 102 kPa to 5.2 cm3? V2 P1 (Boyle’s) P1V1 = P2V2 P2 = P1V1/V2 P2 = (102 kPa)(48cm3)/(5.2cm3) P2 = 940 kPa (Boyle’s) P1V1 = P2V2 V2 = P1V1 / P2 V2 = (290.kPa)(18.9mL)/(104kPa) V2 = 52.7mL Divers must exhale or else the gas in their lungs will expand so much that his lungs could rupture. 5. , V1 P1 6. A gas sample has volume 3.00 dm3 at 101 kPa. What will be the volume if the pressure is reduced to 14.2 kPa?
Using the G° data in your Appendix B, calculate the change in Gibbs free energy for each of the following reactions. In each case, indicate whether the reaction is spontaneous under standard conditions. a) H2 (g) + Cl2 (g) → 2HCl (g) b) MgCl2 (s) + H2O (l) → MgO (s) + 2 HCl (g) c) 2 NH3 (g) → N2H4 (g) + H2 (g) d) 2 NOCl (g) → 2 NO (g) + Cl2 (g) 4. From the values given for ΔH° and ΔS°, calculate ΔG° at 25°C for each of the following reactions. If the reaction is not spontaneous under standard conditions at 298K, at what temperature (if any) would the reaction become spontaneous?
Synthesis of Methyl Stearate Post-Lab Submitted by Matthew Sharma TA: Evan Determining the Limiting Reagent Methyl Oleate (MW= 296.49 g/mol) Amount used = 1.141g (1.141g)(1mol / 296.49g) = 0.003848 mol ∴ The limiting reagent for the reaction is methyl oleate because hydrogen is used in excess Theoretical Yield Methyl Stearate (0.003848 mol)(298.504g/mol product) = 1.1486 g methyl stearate Percent Yield Given the 1:1 stoichiometry of the reaction: 100% x (0.2551g product / 1.1486g theoretical yield) = 22.2% Conclusion A 22.2% yield of synthesized methyl stearate was obtained via the catalytic hydrogenation of methyl oleate in the presence of the catalyst 10% palladium on carbon. The product
Step 2. Heat test tube until all of the O2 has evolved Step 3. Record the amount of O2 produced Observations Mass of O2 produced: 3.915576 grams or .1224 moles Mass of KCl produced: 6.083363 grams or .0816 moles Calculations Chemical Reaction 2KClO3-> 2KCl + 3O2 Theoretical Yield (96/245.1)*10 grams= 3.916 grams of O2 Percent Yield 3.915576/3.916= .99989 *100= 99.998 percent Data Actual amount of Oxygen Produced |3.915576 grams | |Theoretical amount of oxygen Produced |3.916 grams of O2 | |The Percent Yield |99.998 percent | | Results The amount of oxygen produced was almost exactly what was expected with a percent yield of 99.998 percent. The Law of conservation of mass was also up held with there being a combined mass of 10 grams from the resulting O2 and KCl. 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.
palladium on carbon 13 of 22 4/16/12 9:15 PM StudyBlue Flashcard Printing of Lab Final 2211L UGA http://www.studyblue.com/servlet/printFlashcardDeck?deckId=... Which alkyl halide would react fastest in a nucleophilic substitution using silver nitrate in ethanol? 3-bromo3-methylpentane bc its sn1 Which alkyl halide would react fastest in a nucleophilic substitution using sodium iodide in acetone? 1-bromopentane bc its sn2 What is the name of the chemical reagent used as the source of Br2 in the preparation of diphenylacetylene? 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?
Percent Yield Calculations 1) Balance this equation and state which of the six types of reaction is taking place: ____ Mg + ____ HNO3 ( ____ Mg(NO3)2 + ____ H2 Type of reaction: __________________________ 2) If I start this reaction with 40 grams of magnesium and an excess of nitric acid, how many grams of hydrogen gas will I produce? 3) If 1.7 grams of hydrogen is actually produced, what was my percent yield of hydrogen? 4) Balance this equation and state what type of reaction is taking place: ____ NaHCO3 ( ____ NaOH + ____ CO2 Type of reaction: __________________________ 5) If 25 grams of carbon dioxide gas is produced in this reaction, how many grams of sodium hydroxide should be produced? 6) If 50 grams of sodium hydroxide are actually produced, what was my percent yield?
The effect of heat on the expansion of gases is stated in Charles' Law. A gas occupies 1/273.15 more space for each 1° C. rise in temperature and, conversely, 1/273.15 less space for each 1° C. drop in temperature. This fact enabled scientists to determine absolute zero (-273.15° C.), the temperature at which all molecules theoretically stop moving. A gas can be made to expand without the addition of outside heat if the pressure confining the gas is reduced. This principle is stated in Boyle's Law.