* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download energy and rates practice test answers
Water splitting wikipedia , lookup
Nuclear fusion wikipedia , lookup
Asymmetric induction wikipedia , lookup
Multi-state modeling of biomolecules wikipedia , lookup
Supramolecular catalysis wikipedia , lookup
Electrochemistry wikipedia , lookup
Hydrogen-bond catalysis wikipedia , lookup
Chemical equilibrium wikipedia , lookup
Process chemistry wikipedia , lookup
Woodward–Hoffmann rules wikipedia , lookup
Electrolysis of water wikipedia , lookup
Photoredox catalysis wikipedia , lookup
Thermometric titration wikipedia , lookup
Hydroformylation wikipedia , lookup
Marcus theory wikipedia , lookup
Physical organic chemistry wikipedia , lookup
Chemical reaction wikipedia , lookup
Chemical thermodynamics wikipedia , lookup
Rate equation wikipedia , lookup
Strychnine total synthesis wikipedia , lookup
Lewis acid catalysis wikipedia , lookup
Photosynthetic reaction centre wikipedia , lookup
Click chemistry wikipedia , lookup
Reaction progress kinetic analysis wikipedia , lookup
Stoichiometry wikipedia , lookup
George S. Hammond wikipedia , lookup
NAME: SCH 4U ENERGY AND RATES TEST A KNOW COMM INQ MC TOTAL 13 8 24 4 50 PART ONE: KNOWLEDGE (15 marks) MULTIPLE CHOICE (15 marks) For each question below, chose the CAPITAL letter of the answer and place it in the table below. 1. An endothermic reaction is one where a. heat is transferred from the surroundings into a system b. heat is transferred from a system into the surroundings c. kinetic energy is transformed into potential energy d. there is no transfer of heat e. none of the above 2. The molar heat of vaporization of water is 42 kJ/mol. How much energy is released by the condensation of 3.0 g of water? a. 0.88 kJ d. 250 kJ b. 7.0 kJ e. 0.07 kJ c. 130 kJ 3. What is another way to write the following equation? C2H6(g) C2H2(g) + 2H2(g) ΔH = 3.2 102 kJ/mol a. b. c. d. e. 4. C2H6(g) C2H6(g) + 2H2(g) + 3.2 102 kJ C2H6(g) + 3.2 102 kJ C2H2(g) + 2H2(g) 2H2(g) + C2H2(g) + 3.2 102 kJ C2H6(g) C2H6(g) – 3.2 102 kJ C2H2(g) + 2H2(g) none of the above Which statement concerning the accompanying diagram is true? a. b. c. d. e. H is positive the system is endothermic the system releases heat to the surroundings the heat content of the reactants is less than the heat content of the products the enthalpy of the products is greater than the enthalpy of reactants 5. For which one of the following substances is the standard enthalpy of formation, H°f, equal to zero? a. water [H2O(l)] d. carbon dioxide [CO2(g)] b. lead [Pb(s)] e. tin [Sn(g)] c. carbon dioxide [CO2(s)] Use the following data to determine the ΔH of vaporization for silicon tetrachloride at its boiling point. 6. a. –30.6 kJ b. +30.6 kJ c. –609.6 kJ 7. d. +609.6 kJ e. +1249.8 kJ The combustion of magnesium in air is very exothermic. If the given two reactions and their heats of reaction were used to determine the heat of combustion of magnesium the result would be a. x + y d. x – 2y b. x – y e. not enough information is given c. 2x – y 8. a. b. c. d. e. 9. The following property can be measured to determine the rate of the reaction change in mass change in colour change in volume change in pressure all of the above depending on the reaction In the reaction, N2 (g) + 2 O2 (g) NO2 (g), if the concentration changes from 0.45 mol/L to 1.00 mol/L in 2 minutes, what is the overall rate of production of nitrogen dioxide in the system? a. 3.64 mol/(L·min) d. 12.6 mol/(L·min) b. 0.275 mol/(L·min) e. 0.333 mol/(L·min) c. 0.137 mol/(L·min) 10. a. b. c. d. e. The presence of a catalyst is thought to increase the rate of a reaction by changing the products that are formed in the reaction decreasing the enthalpy change of the reaction increasing the enthalpy change of the reaction decreasing the activation energy of the reaction increasing the activation energy of the reaction 11. a. b. c. d. e. If for the reaction aX + bY products, the rate law is determined to be , r= [X]1[Y]0then the order of the reaction is 0 increasing the concentration of Y will have no effect on the rate increasing the concentration of X will have no effect on the rate increasing the concentration of Y will increase the rate of the reaction there is no way to determine the value of k 12. The amount of energy required for a reaction to begin is known as a. enthalpy change d. kinetic energy b. reaction energy e. potential energy c. activation energy 13. When a reaction is broken down into a number of elementary steps, this is known as a a. reaction progression d. reaction step b. reaction mechanism e. none of the above c. reaction pattern 14. Consider the above reaction mechanism. The rate-determining step of this reaction is a. b. c. d. e. elementary step 1 elementary step 2 elementary step 3 elementary steps 2 and 3 impossible to tell from this information PART TWO: COMMUNICATION (8 marks) 1. A reaction has a molar enthalpy of reaction of -45 kJ/mol and the activation energy for the reverse reaction is 120 kJ/mol. Draw a potential energy diagram for the reaction. (4 marks). 2. Using a diagram and the concept of kinetic energy, explain why an increase in temperature increases the rate of a chemical reaction. (4 marks) PART THREE: INQUIRY (24 marks 1. Determine the amount of heat required to heat 1.50 L of water from 15 °C to the boiling point in a 1.20 kg iron pot. (3 marks) q = mcwaterΔT + mcironΔT = (1.50 kg)(4.18 kJ/kg°C)(100-15°C) + (1.20 kg)(0.45 kJ/kg°C)(100-15°C) = 530 kJ + 46 = 576 kJ 2. A) Calculate the heat of combustion for pentane using HEATS OF FORMATION. (4 marks) C5H12(l) + 8 O2(g) 5 CO2(g) + 6 H2O(g) ΔH= Σ Hf products - Σ Hf reactants = [5 CO2(g) + 6 H2O(g)] – [C5H12(l) + 8 O2(g)] = [5(-393.5 kJ/mol) + 6(-241.8 kJ/mol)] – [-173.5 kJ/mol+ 8(0)] = (-1967.5- 1450.8 +173.5) kJ/mol = -3244.8 kJ/mol B) Calculate the mass of pentane required to heat 250.0 g of ice at -6°C to 85°C. (7 marks) qgained water = mciceΔT1 + mlf + mcliquid waterΔT2 = (250 g)(2.1J/g°C)(0-(-6) °C) + (250 g)(333 J/g) + (250 g)(4.18J/g°C)(85-0°C) = 3150 J + 83 250 J + 88 825 J = 175 kJ qlost pentane = -qgained water = - 175 kJ n= q/ΔH = -175 kJ/-3244.8 kJ/mol = 0.054 mol m=nMM = 0.054 mol(72.17 g/mol) = 3.9 g 2. Calculate ΔH for the reaction : 3 N2H4 (l) + 4 ClF3 (g) 3 N2 (g) + 12 HF(g) + 2 Cl2 (g), using the following data. (5 marks) 1) 2 ClF3 (g) + 2 NH3 (g) N2 (g) + 6 HF(g) + Cl2 (g) 2) N2H4 (l) + O2 (g) N2 (g) + 2 H2O (l) ΔH= -622 kJ 3) 4 NH3 (g) + 3 O2 (g) 2 N2 (g) + 6 H2O(l) ΔH= -1530 kJ 2 x 1) 4 ClF3 (g) + 4 NH3 (g) 2 N2 (g) + 12 HF(g) + 2 Cl2 (g) 3 x 2) 3 N2H4 (l) + 3 O2 (g) 3 N2 (g) + 6 H2O (l) R 3) 2 N2 (g) + 6 H2O(l) 4 NH3 (g) + 3 O2 (g) 3 N2H4 (l) + 4 ClF3 (g) 3 N2 (g) + 12 HF(g) + 2 Cl2 (g) 3. ΔH= -1196 kJ ΔH= -2392 kJ ΔH= -1866 kJ ΔH= 1530 kJ ΔH= -2728 kJ Given the experimental data below, determine the rate equation, including the value for k for the following reaction. (5 marks) 3 A (aq) + 2 B (aq) + C (aq) products [B] [C] Rate (mol L-1 s-1) 0.400 0.100 0.200 1.50 x 10-3 0.400 0.100 0.400 3.00 x 10-3 1.600 0.100 0.200 1.50 x 10-3 0.400 0.500 0.200 3.75 x 10-2 [A] For A compare 1 and 3; [A] x 4, rate x1, therefore 0 order for A For B compare 1 and 4; [B] x 5, rate x5 = 52, therefore 2nd order for B For C compare 1 and 2; [C] x 2, rate x2, therefore 1st order for C r=k[B]2[C] sub in trial 1 data to solve for k 1.5x10-3=k(0.100)2(0.200) k=0.75 r=0.75[B]2[C] PART FOUR: MAKING CONNECTIONS (4 marks) 1. Using specific examples, explain how we use temperature, surface area, concentration and catalysts in order to speed up the rate of chemical reactions to our advantage. (4 marks)