General chemistry II, Cheat Sheet of Chemistry

Download General chemistry II and more Cheat Sheet Chemistry in PDF only on Docsity! CHEMISTRY 101 Name ______________________________ Hour Exam II March 28, 2023 Signature ___________________________ McCarren Section _____________________________ “Obstacles don’t have to stop you. If you run into a wall, don’t turn around and give up. Figure out how to climb it, go through it, or work around it.” – Michael Jordan This exam contains 17 questions on 10 numbered pages. Check now to make sure you have a complete exam. You have one hour and thirty minutes to complete the exam. Determine the best answer to the first 15 questions and enter these on the special answer sheet. Also, circle your responses in this exam booklet. Show all of your work and provide complete answers to questions 16 and 17. 1-15 (30 pts.) _________ 16 (18 pts.) _________ 17 (12 pts.) _________ Total (60 pts) _________ Useful Information: 1 L = 1000 mL (exactly) Always assume ideal behavior for gases (unless explicitly told otherwise). PV = nRT R = 0.08206 L·atm/mol·K K = C + 273 NA = 6.022 × 1023 = 1 mole Standard temperature and pressure (STP) is 1.0 atm and 273 K. Solubility Rules: 1. Most nitrate salts are soluble. 2. Most salts of sodium, potassium, and ammonium cations are soluble. 3. Most chloride salts are soluble. Exceptions: silver(I), lead(II), and mercury(I) chloride. 4. Most sulfate salts are soluble. Exceptions: calcium, barium, and lead(II) sulfate. 5. Most hydroxide salts can be considered insoluble. Soluble ones: sodium, potassium, ammonium, and calcium hydroxide. 6. Consider sulfide, carbonate, and phosphate salts to be insoluble. Soluble ones: sodium, potassium, and ammonium. Chemistry 101 Spring 2023 Hour Exam II Page No. 2 Part 1: Multiple Choice 1. Which is true about a limiting reactant? The limiting reactant always is the reactant that… a. can produce less product. b. has the largest coefficient in the balanced equation. c. remains in the container after the reaction is complete. d. has the greatest molar mass. e. has the smallest number of moles before the reaction. 2. Consider the following balanced equation which shows acetylene gas burning in oxygen. Balance the equation in standard form (using lowest whole number coefficients) and give the coefficient in front of the oxygen gas. C2H2(g) + O2(g)  CO2(g) + H2O(g) a. 1 b. 2 c. 3 d. 4 e. 5 Consider the equation shown below for the reaction between solid sulfur (S8) and solid carbon to form liquid CS2. Use this reaction to answer the next two questions. S8(s) + 4C(s)  4CS2(l) 3. Each time 2.50 moles of S8 react, __________ moles of CS2 form. a. 2.50 moles b. 5.00 moles c. 7.50 moles d. 10.0 moles e. 12.5 moles. 4. Each time 65.0 grams of CS2 forms, _________ moles of S8 were required. a. 0.214 moles b. 0.427 moles c. 0.853 moles d. 3.41 moles e. 54.7 moles Chemistry 101 Spring 2023 Hour Exam II Page No. 5 Consider the reaction between aqueous magnesium nitrate and aqueous potassium hydroxide as shown below. Use this reaction to answer the next three questions. Mg(NO3)2(aq) + 2KOH(aq)  Mg(OH)2(s) + 2KNO3(aq) 11. Select the balanced complete ionic equation for this reaction. a. Mg+2(aq) + 2NO3 -(aq) + 2K+(aq) + 2OH-(aq)  Mg(OH)2(s) + 2K+(aq) + 2NO3 -(aq) b. Mg+2(aq) + (NO3 -)2(aq) + 2K+(aq) + 2OH-(aq)  Mg(OH)2(s) + 2K+(aq) + (NO3 -)2(aq) c. Mg+2(aq) + 2NO3 -(aq) + K+(aq) + OH-(aq)  Mg(OH)2(s) + K+(aq) + NO3 -(aq) d. Mg+(aq) + NO3 -(aq) + K+(aq) + OH-(aq)  MgOH(s) + K+(aq) + NO3 -(aq) e. Mg+2(aq) + NO3 -(aq) + K+(aq) + OH-(aq)  Mg(OH)2(s) + K+(aq) + NO3 -(aq) 12. When a 100.0 mL solution of 0.200 M aqueous magnesium nitrate is mixed with 100.0 mL of 0.200 M aqueous potassium hydroxide, which ion limits the amount of product that can be produced? a. The magnesium ion b. The potassium ion c. The nitrate ion d. The hydroxide ion e. Both magnesium ion and the hydroxide ion limit the amount of product. 13. After mixing the two solutions in #12, which ions are remaining in the solution after the reaction? a. magnesium and potassium ions b. magnesium and hydroxide ions c. nitrate and potassium ions d. nitrate, potassium, and hydroxide ions e. magnesium, nitrate, and potassium ions Chemistry 101 Spring 2023 Hour Exam II Page No. 6 Consider the reaction between hydrogen gas and oxygen gas to form liquid water. 2H2 + O2  2H2O We have seen this reaction several times in class, in both the “pop” bottles and balloons. Suppose this reaction begins with hydrogen gas and oxygen gas in a sealed container with no water present. After the reaction, the container held 20.0 g water, 10.0 g leftover oxygen gas, and no hydrogen gas. 14. What mass of hydrogen gas was required to produce 20.0 grams water? a. 0.555 grams b. 1.11 grams c. 2.24 grams d. 4.48 grams e. 40.4 grams 15. What was the total mass of oxygen gas present before the reaction? a. 0.865 grams b. 10.0 grams c. 17.8 grams d. 20.0 grams e. 27.8 grams Please go on to the next page. Chemistry 101 Spring 2023 Hour Exam II Page No. 7 Part 2: Free Response 16. Recall the lab activity in which you observed the combinations of several aqueous solutions. Use the solubility rules on the equation sheet to help answer the following questions related to these solutions. a. The table below shows possible combinations of aqueous solutions of several salts. For each combination, determine whether or not a precipitate formed. Write “ppt” or “no” in each of the boxes below accordingly. b. For each combination above which resulted in the formation of a precipitate, give the balanced molecular and net ionic equations in the space below. Be sure to include all phases and charges as required, and label which is the molecular equation and which is the net ionic equation. Please go on to the next page. iron(III) nitrate sodium sulfate potassium chloride calcium nitrate sodium carbonate Chemistry 101 Spring 2023 Hour Exam II Page No. 10 c. In another scenario, you find an unknown white solid which consists of a bicarbonate compound and some unknown cation X consisting of an ion of one element. This compound reacts with sulfuric acid according to the balanced equation below and similarly inflates a balloon. H2SO4(aq) + 2XHCO3(s)  2H2O(l) + 2CO2(g) + X2SO4(aq) This reaction occurs when 50.0 mL of 0.100 M H2SO4 and 0.680 g of the unknown solid react completely, with no excess reactant remaining. What is the identity of X? Show work to support your answer. STOP. You have reached the end of the exam. Nothing written after this page will be graded. Chemistry 101 Spring 2023 Hour Exam II Page No. 11 SCRATCH PAPER Nothing written on this page will be graded. Chemistry 101 Spring 2023 Hour Exam II Page No. 12