1. Balance the following chemical equations: a. C 8 H 18 + O 2 à CO 2 + H 2 O. b. B 5 H 9 + O 2 à B 2 O 3 + H 2 O. c. S 8 + Cl 2 à S 2 Cl 2

Size: px

Start display at page:

Download "1. Balance the following chemical equations: a. C 8 H 18 + O 2 à CO 2 + H 2 O. b. B 5 H 9 + O 2 à B 2 O 3 + H 2 O. c. S 8 + Cl 2 à S 2 Cl 2"

Clara Fletcher
5 years ago
Views:

1 EXAM 2 PRACTICE QUESTIONS NOTE- THIS IS ONLY A SELECTION OF POSSIBLE TYPES OF QUESTIONS: REFER TO THE EXAM 2 REVIEW GUIDELINES FOR THE LIST OF LEARNING TARGETS. There will likely be other questions on the exam not shown here, e.g., Net Ionic Equations, etc. 1. Balance the following chemical equations: a. C 8 H 18 + O 2 à CO 2 + H 2 O b. B 5 H 9 + O 2 à B 2 O 3 + H 2 O c. S 8 + Cl 2 à S 2 Cl 2 2. Change these word equations into formula equations and balance them a. Lithium metal reacts with water to produce hydrogen gas and aqueous lithium hydroxide b. Copper metal placed in a zinc nitrate solution produces aqueous copper (I) nitrate plus zinc metal. 3. A gas sample is collected in a balloon. What happens to the density of the gas sample as the sample is heated? a. decreases b. increases c. does not change d. could increase or decrease, depending on how much it was heated liters of oxygen gas is produced at 1.00 atm of pressure. It is to be compressed and stored in a 20.0 liter cylinder. If temperature is constant, calculate the pressure of the oxygen in the cylinder. a. 125 atm b. 4.0 atm c atm d atm 5. A balloon has a volume of 5.00 liters of 22 C and 1.00 atmosphere of pressure. What will be the balloon's volume in liters if the pressure is increased to 3.00 atmospheres at 22 C? a b c. 1.30

2 6. What volume in liters is occupied by 8.22 g of SO 2 gas confined at a pressure of 1200 torr (1.578atm) at 75.0 C? R = liter atm/mol K a b c d A mixture of helium, argon and krypton is made and stored in a cylinder at a total pressure of 2.80 atm (2128 torr). The partial pressure of helium is 900 torr (1.184 atm), and that of argon is 250 torr (0.329 atm). What is the partial pressure of krypton in the mixture? a atm b atm c torr d. 978 torr 8. When a liquid sample is taken from sea level to a higher elevation, what happens to the external (atmospheric) pressure on the liquid and the boiling point of the liquid? a. both decrease b. both increase c. pressure goes down, but boiling point goes up d. pressure goes up, but boiling point goes down 9. The vapor pressure of a liquid a. decreases with increasing temperature b. is independent of temperature c. is equal to one atmosphere at the normal boiling point d. cannot be measured 10. What is the most likely possible cause for water to have a high specific heat and ability to dissolve many ionic compounds? a. it s molar mass b. it s molecular structure causing hydrogen bonding interactions c. that it s made from two gases d. it s ionic bonds 11. Carbon tetrachloride, CCl 4, is very slightly soluble in water, a polar solvent, but quite soluble in toluene, a nonpolar solvent. What can be inferred about the nature of the CCl 4 molecule? a. It is ionic. b. It is polar. c. It is nonpolar. d. Nothing can be inferred.

3 12. What volume of a 10.00% (w/v) solution of sugar is needed to provide 2.00 g of sugar? a liter b ml c ml d ml 13. How many grams of solid KCl are needed to prepare 250 ml of M solution? a b c d How many ml of 6.00 M HCl are needed to prepare 1500 ml of M HCl solution? a b. 125 c d Which of the following pass through both osmotic and dialysis membranes? a. solvent molecules b. large molecules c. small molecules that are larger than solvent molecules d. more than one response is correct 16. Express the following concentration of solution in terms of molarity: 3.00 L of solution contains 1.75 mol of solute. a M b M c M d. too little information to know 17. One test to determine if a mixture is a true solution or a colloid is. a. physical state of the mixture b. boiling point elevation c. light scattering d. color 18. The concept of entropy a. is employed to explain how energy can be stored b. is employed to explain how an exothermic reaction can become endothermic c. is employed as an indicator of disorder in a system d. explains why most chemical reactions are endothermic

4 19. Which of the following states of matter generally has the lowest entropy? a. a crystalline solid b. a liquid c. a gas d. two of the three have virtually the same entropy 20. The reaction conditions for a specific reaction,, are correct, but the reaction does not occur. What could be the reason? a. There are no collisions between the molecules. b. The collisions of the particles with the container walls remove the required energy because it is transferred to the container molecules. c. The orientation of the molecules with respect to each other is not correct for the reaction to occur. d. There is more than one answer. 21. Catalytic can do which of the following: a. increase the amount of energy given off of an exothermic reaction b. lower activation energy c. make a reaction proceed at a lower temperature d. there is more than one correct response 22. The following question(s) refer to the following equilibrium in which all reactants and products are gases: CH 4 + H 2 O CH 3 OH + H 2 + heat Remove H 2 from the mixture. a. shifts left b. shifts right c. no effect d. can shift to right or left Cool the mixture. a. shifts left b. shifts right c. no effect d. can shift to right or left 23. Which method can be used to produce a timed-release medication? a. The patient is given the medication in small doses over time, rather than one larger dose.

5 b. The patient is to take the medication two or three times a day. c. The medication is provided in special capsules that are subdivided into smaller, pulverized portions of the medicinal compound. d. The medication compound is produced in very small amounts and each is coated with a material of varying thickness 24. Complete and balance the equation for this single replacement reaction (Zn forms a 2+ ion sulfate ion is SO 4 2- ): Zn + H 2 SO 4 à 25. Complete and balance the equation for this double replacement reaction: BeCl 2 + KOH à 26. Complete and balance the equation for this combination reaction: Na + F 2 à (changed from earlier version) 27. Complete and balance the equation for this decomposition reaction: H 2 O à 28. Provide the oxidation number for each atom in the polyatomic ion SO 4 2- (charge corrected from earlier version) Sulfur: Oxygen: 29. CaSO 4 is obtained by reacting 4.50g of Ca and 3.5g of H 2 SO 4? (And which is the limiting reactant?) Ca (s) + H 2 SO 4 (aq) à CaSO 4 (aq) + H 2 (g) a. What is the theoretical yield of CaSO 4? b. What is the limiting reactant? c. Is this a redox reaction if so, what is reduced, what is oxidized.

6 30. (A gas occupies a volume of 250. ml at 5.25 atm pressure. When the pressure is reduced to 1.50 atm, what volume will the gas occupy (assuming constant temperature)? 31. An expandable balloon contains L of He at 1.20 atm and 20 C. The balloon rises to an altitude of 10,000 feet, where the pressure is atm and the temperature is 5 C. What is the volume of the balloon at this altitude? 32. How many grams of nitrogen gas will be needed to fill a balloon to a volume of 4.5 L at STP (O o C, 1atm) 33. How many moles of KMnO 4 are in 220 ml of 1.2 M KMnO 4 solution? 34. What volume of 12.0 M HCl is required to prepare 1.00 L of 3.00 M HCl?

7 35. Given the equation: CuSO 4 + 2NaOH à Cu(OH) 2 + Na 2 SO 4 Calculate the amount of ml of 0.50 M NaOH solution that will react with 15 ml of 0.20 M CuSO 4 solution.

c. K 2 CO 3 d. (NH 4 ) 2 SO 4 Answer c

c. K 2 CO 3 d. (NH 4 ) 2 SO 4 Answer c Chem 130 Name Exam 2, Ch 4-6 July 7, 2016 100 Points Please follow the instructions for each section of the exam. Show your work on all mathematical problems. Provide answers with the correct units and