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?
The precipitate(s) for the above reaction is/are: A) Silver nitrate B) Aluminum bromide C) Silver bromide D) Aluminum nitrate E) There is no precipitate 18 – 37: For each of the two REDOX reactions below, perform the following: A) Balance the following equation and place the final answer in the boxes provided; show all work on the exam pages. B) Identify the oxidizing and reducing reagents. C) Assign the oxidation numbers to the elements in bold on both sides of the equation. D) Identify the oxidation and reduction half-reactions by placing LEO and GER, respectively, above the arrows in each half-reaction. E) NOTE that illegible writing will not be graded.
Concept Explorations 8.29. Periodic Properties I A hypothetical element, X, has the following ionization energy values: First ionization energy: 900 kJ/mol Second ionization energy: 1750 kJ/mol Third ionization energy: 14,900 kJ/mol Fourth ionization energy: 21,000 kJ/mol Another element, Y, has the following ionization energy values: First ionization energy: 1200 kJ/mol Second ionization energy: 2500 kJ/mol Third ionization energy: 19,900 kJ/mol Fourth ionization energy: 26,000 kJ/mol * a. To what family of the periodic table would element X be most likely to belong? Explain? * X belongs to Group 2 of the periodic table because it has a low first and second ionization energy, however, a higher second and third.
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
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.
Practice Question for Exam 2 Chem 103 |A chemical reaction requires 30.77 kJ. How many kilocalories does this correspond to? | |A) 7,354 kcal B) 7.354 kcal C) 128.7 kcal D) 0.1287 kcal E) 30.77 kcal | |776 J is the same quantity of energy as | |A) 7.76 × 105 kJ. B) 1.85 × 102 kcal. C) 0.185 kcal.
Chemical Kinetics Exam Name:______________________________ Part A: Multiple Choice Value: 42 marks Suggested Time: 60 minutes INSTRUCTIONS: For each question, select the best answer and record your choice on the Response Form provided. Using an HB pencil, completely fill in the circle that has the letter corresponding to your answer. 1. Consider the reaction: Ca(s) + 2H2O(l) ( Ca(OH)2(aq) + H2(g) At a certain temperature, 2.50 g Ca reacts completely in 30.0 seconds. The rate of consumption of Ca is A.
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?