General Chemistry Study Guide

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1 General Chemistry 1311 Study Guide Name : Louise K number: Date: Oct Instructor: Jingbo Louise Liu kfjll00@tamuk.edu 1

2 Chapter 04 & 05 (10 questions required and 5 questions for extra credit) Credited Questions 1. Which of the following compounds is insoluble in water? a. NaNO 3 b. Na 2 CO 3 c. CuS d. (NH 4 ) 2 SO 4 2. According to the solubility rules, which of the following compounds will be soluble in water? a. NaCl b. PbCO 3 c. AgCl d. CaSO 4 3. When aqueous solutions of NaOH and H 2 SO 4 are mixed, a reaction occurs. What ions, if any, are the spectator ions in this reaction? a. Na + & SO 4 b. H + & SO 4 c. H + & OH - d. NH + 4 & SO 4 4. The correct net ionic equation for the process which occurs when aqueous solutions of the electrolytes AgNO 3 and Na 2 S are mixed is: a. Ag + (aq) + Na 2 S (s) Na + (aq) + Ag 2 S(s) b. 2Ag + (aq) + S (aq) Ag 2 S(s) c. Ag + (aq) + S (aq) Ag 2 S(aq) d. AgNO 3 (aq) + Na 2 S (s) NaNO 3 (aq) + Ag 2 S(s) 5. The net ionic equation for the reaction between aqueous solutions of HCl and KOH is, a. H + (aq) + OH - (aq) H 2 O (aq) b. HCl (aq) + OH - (aq) H 2 O(l) + Cl - (aq) c. H + (aq) + OH - (aq) H 2 O (l) d. H + (aq) + OH - (aq) H 2 O (g) 6. What volume of a M solution of HCl is required to neutralize a solution 0.200M 10.0 ml of KOH solution? a. 20 ml b. 10 ml c. 100 ml d. 5 L 7. What are the products when aqueous solutions of HCl and Na 2 CO 3 react? a. NaCl and H 2 CO 3 b. Na 2 CO 3 and H 2 CO 3 c. NaCl, H 2 O and CO 2 d. HCl and CaSO 4 8. Equation: 3Cu(s) + 8HNO 3 (aq) 2NO(g) + 3Cu(NO 3 ) 2 (aq) + 4H 2 O(l) In the above reaction, the element oxidized is and is the reducing agent. a. Cu (s) and HNO 3 b. Cu (s) and Cu (s) c. Cu(NO 3 ) 2 (aq) and HNO 3 d. NO and Cu 9. What is the oxidation number of the polyatomic ion MnO - 4? a. +4 b. +5 c. +6 d In the equation shown below, which species, if any, is the oxidizing agent? Equation: Cr 2 O 7 + 2OH - 2CrO 4 + H 2 O a. Cr 2 O 7 b. CrO 4 c. OH - d. none of them is reducing agent. 2

3 11. Balance the following chemical equation: CH 3 OH (l) + O 2 (g) CO 2 (g) + H 2 O(g) a. CH 3 OH (l) + O 3 (g) CO 2 (g) + 2 H 2 O(g) b. 2 CH 3 OH (l) + 3 O 2 (g) 2 CO 2 (g) + 4 H 2 O(g) c. CH 3 OH (l) + 2 O 2 (g) CO 2 (g) + 2 H 2 O(g) d. CH 3 OH (l) + O 2 (g) CO 2 (g) + H 2 O(g) 12. What amount of bromine reacts with 4.0 mol of aluminum to produce AlBr 3? 2 Al(s) + 3 Br 2 (g) 2 AlBr 3 (s) a. 2.0 mol b. 4.0 mol c. 6.0 mol d. 12 mol 13. What mass of sodium will react with 1.23 g of chlorine gas to produce sodium chloride? 2 Na(s) + Cl 2 (g) 2 NaCl(s) a g (1.23/(35.45*2) * 2* b g c g d g 14. Which of the following statements concerning electrolytes are correct? 1) Soluble compounds are always strong electrolytes. 2) Elements, such as N 2, are weak electrolytes. 3) Strong acids, such as HCl, are strong electrolytes. a. 1 only. b. 2 only. c. 3 only. d. 2 and Which of the following compounds is a strong electrolyte? a. HNO 3 b. HNO 2 c. NH3 d. H 2 O e. HF ( strong acid, strong base, and soluble salts are usually strong electrolyte.) 16. Which of the following compounds is soluble in water? a. BaSO 4 b. Cu 2 O c. AgBr d. NaClO 3 e. Hg 2 Cl 2 ( compounds contains 1A elements (Na, K, NH 4 + ) are soluble. ) 17. In accordance with the solubility rules, which of the following is true when solutions of KCl(aq) and AgNO 3 (aq) are mixed? a. No precipitate will form. b. KAg 2+ will precipitate and Cl - and NO 3 - will be spectator ions. c. KNO 3 will precipitate and Ag + and Cl - will be spectator ions. d. ClNO 3 will precipitate and K + and Ag + will be spectator ions. e. AgCl will precipitate and K + and NO 3 - will be spectator ions. 18. What is the name of H 3 O +? a. Proton b. Hydronium c. Trihydrogen oxide cation d. Water cation 3

4 19. Which statement is correct in terms of the ph definition? a. ph is the measurement of concentration of an aqueous solution. b. ph is the measurement of acidity of an aqueous solution and defined as ph = -log[h + ] c. ph is the measurement of conductivity of an aqueous solution. d. ph is the measurement of acidity of an aqueous solution and defined as ph = -log[oh - ]. Credited Questions 11. The net ionic equation of FeBr 2 and AgNO 3 is, a. Ag + (aq) + Br - (s) AgBr (s) b. Ag + (aq) + Br - (aq) AgBr (s) c. Ag + (aq) + Br - (aq) AgBr (aq) d. AgNO 3 (aq) + FeCl 2 (aq) NaNO 3 (aq) + AgBr (s) 12. The net ionic equation for the reaction between aqueous solutions of H 2 CO 3 and NaOH is, a. 2H + (aq) + CO 3 (aq) H 2 O (l) + CO 2 (g) b. 2H + (aq) + CO 3 (aq) H 2 O (aq) +CO 2 (g) c. H + (aq) + OH - (aq) H 2 O (aq) d. H + (aq) + OH - (aq) H 2 O (g) 13. What is the oxidizing agent in the redox reaction: C 2 H 6 O + Cr 2 O 7 + H + C 2 H 4 O + H 2 O + Cr 3+ a. Cr 2 O 7 b. H 2 O c. C 2 H 6 O d. H + 4

5 1. Data: 2SO 2 (g) + O 2 (g) 2SO 3 (g) ΔH = -198 kj Use the data above to calculate the standard enthalpy change for the reaction below. Reaction: 2SO 3 (g) O 2 (g) + 2SO 2 (g) ΔH =? a kj (reverse reaction) b kj c kj d kj 2. Data: (1) 2H 2 (g) + O 2 (g) 2H 2 O(g) ΔH = kj (2) 2H 2 (g) + O 2 (g) 2H 2 O(l) ΔH = kj On the basis of the above data, determine the ΔH of H 2 O (g) H 2 O(l)? a kj (switch the direction of reaction (1) and change the sign of ΔH, (483.6+(-571.6)) b kj c kj d kj 3. Data: SO 2 (g) + ½O 2 (g) SO 3 (g) ΔH = kj Given the above data, calculate the enthalpy change ΔH when 120 g of SO 2 is converted to SO 3. a kj b kj c kj d kj moles of SO 2 = 120/ (molar mass), 120/( *2) *(-99.1) 4. A combustion reaction occurs in a bomb calorimeter. The temperature of the calorimeter and the 3.5 mol of water rose from 22.5 C to 32.5 C. The heat Determine the heat released by the combustion. (c = 4.18 J / g K, q= c m T) a kj b kj c kj d kj (3.5*18.016*( ) 5. Which equation is associated to the standard enthalpy of formation? a. CO(g) + NO(g) CO 2 (g) + ½ N 2 (g) b. 2Ag(s) + Cl 2 (g) 2AgCl(s ) c. ½ Ca(s) + C(graphite) + 3/2 O 2 (g) CaCO 3 (s) d. H 2 (g) + 2C(graphite) + N 2 (g) 2HCN(g) (find the equation only has one product, the product has only one mole) 6. Data: 2Ba(s) + O 2 (g) 2BaO(s) ΔH = kj (1) BaCO 3 (s) Ba (s) + CO 2 (g) + ½O 2 (g) ΔH = kj (2) Given the data above, calculate ΔH for the reaction below: BaO(s) + CO 2 (g) BaCO 3 (s) a kj b kj c kj d kj (Switch the direction of equation (1), and then divided by 2, switch the direction of equation (2): (-)( )/2 + (-)(+822.5) =

6 1. Steam is subject the phase change mol of steam at C is cooled to ice at C. Calculate total heat released. (5 pts) H cond. = kj/mol, H fus = 6.01 kj/mol, C (liquid water ) = J/(mol / C), C ice = J/(mol / C). 100 C H 1 = moles H cond. H 2 = moles c liquid T 0 C H 3 = moles H fus -40 C H 4 = moles c ice T H 1 H 2 H 3 H 4 H *40.67 = kj H *75.40*(100)/1000 = 9.42 kj H *6.01 = 7.52 kj H * * (40) / 1000 = 1.82 kj Total heat released = kj 2. Explain what the kinetics-molecular theory is (5 pts) Postulate 1: Particle Volume 1 Because the volume of an individual gas particle is so small compared to the volume of its container, the gas particles are considered to have mass, but no volume. Postulate 2: Particle Motion 2 3 Gas particles are in constant, random, straight-line motion except when they collide with each other or with the container walls. Postulate 3: Particle Collisions Collisions are elastic therefore the total kinetic energy (Ek) of the particles is constant. 6

7 3. Explain what the significance of different variable is in the ideal gas law. Meaning Commonly used unit P Partial pressure of gases atm (standard atmosphere) V Volume of the gas container L (liter) n Moles of gases mol T Absolute temperature K (Kelvin) R Ideal gas constant or universal constant atm L/(mol K) 4. Define three rules of thermo-chemistry. (5 pts) H and amount of substances H of forward and reverse reaction Hess Law Rules of thermo-chemistry The enthalpy change is directly proportional to the amount (moles) of the substances of interest. The enthalpy change for the forward reaction has the same digit but opposite sign compared with its reverse direction. The total enthalpy change for the overall reaction is the sum of the enthalpy changes for the individual reactions. 5. A 1.57 g sample of an unknown vapor occupies ml at C and mmhg. The empirical formula of the compound is CH 2. What is the molecular formula of the compound? The vapor behaves as an ideal gas. (5 pts) PV = nrt Molar mass = mass / moles mmhg To atm /760 = ml To liter /1000 = C To Kelvin = moles PV 1.033*0.5/( *331.63) = RT molar mass Mass 1.57/ = moles Molar mass of g/mol *2 = Empirical formula Molecular Formula (CH 2 )x X = / = C 6 H 12 is your molecular formula 7

Name. Practice Test 2 Chemistry 111

Name. Practice Test 2 Chemistry 111 Name Practice Test 2 Chemistry 111 1) In the aqueous reaction of K 2 SO 4 (aq) + Ba(NO 3 ) 2 (aq) BaSO 4 (s) + 2KNO 3 (aq), which ions are the spectator ions? A) Ba 2+ 2- and SO 4 B) Ba 2+ and K + C) Ba