MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

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1 CHM1025 Exam 4 Chapters 9, 10, & 13 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which of the following statements is false? 1) A) The percent yield = x 100% B) The theoretical yield is the amount of product that can be made based on the amount of limiting reagent. C) The limiting reactant is completely consumed in a chemical reaction. D) The actual yield is the amount of product actually produced by a chemical reaction. E) All of the above are true statements. 2) Consider the following generic chemical equation: 2A + 5B C + 3D If you react 4 units of A with 10 units of B, which statement is TRUE? A) Substance C cannot be formed from this reaction. B) Substance B will be the limiting reactant. C) Substance A will be the limiting reactant. D) There are equivalent amounts of A and B. 3) In order to to determine the limiting reactant in a particular reaction, one must know each of the following EXCEPT A) the coefficient of each reactant in a balanced equation B) the molar mass of each reactant present C) the mass of each product formed D) the mass of each reactant present 4) A tricycle factory uses the following items to produce one tricycle: 3 tires, 1 frame, and 2 pedals. If the factory has available 270 tires, 90 frames, and 170 pedals, which item would limit the amount of complete tricycles that can be assembled. A) pedals B) frames C) both tires and frames are limiting D) tires 5) Given that 4 NH O 2 4 NO + 6 H 2 O, if 3.00 mol NH 3 were made to react with excess of oxygen gas, the amount of H 2 O formed would be, A) 6.00 mol B) 3.00 mol C) 2.00 mol D) 4.50 mol 2) 3) 4) 5) 6) Which among the following statements is TRUE? 6) A) As the energy increases, the frequency of radiation decreases. B) Red light has a shorter wavelength than violet light. C) As the wavelength increases, the frequency also increases. D) The wavelength of light is inversely related to its energy.

2 7) The number of cycles of a wave that passes a stationary point in one second is called its 7) A) wavelength B) crest C) frequency D) trough 8) What is the correct order of the electromagnetic spectrum from shortest wavelength to longest? 8) A) Radio Waves X-rays Ultraviolet Radiation Visible Light Infrared Radiation Microwaves Gamma Rays B) Visible Light Infrared Gamma Rays X-rays Ultraviolet Radiation C) Gamma Rays X-rays Infrared Radiation Visible Light Ultraviolet D) Gamma Rays X-rays Visible Light Ultraviolet Radiation Infrared E) Gamma Rays X-rays Ultraviolet Radiation Visible Light Infrared 9) The subshell letter: 9) A) specifies the principal shell of the orbital. B) specifies the 3-D shape of the orbital. C) specifies the maximum number of electrons. D) specifies the principal quantum number of the orbital. 10) "When filling orbitals of equal energy, electrons fill them singly first with parallel spins." This is known as: A) Ground state B) Bohr's model C) Pauli exclusion principle D) Hund's rule 10) 11) The size of an atom generally increases 11) A) up a group and from left to right across a period. B) up a group and from right to left across a period. C) down a group and from left to right across a period. D) down a group and from right to left across a period. E) up a group and diagonally across the Periodic Table.

3 Short Answer Problems. Show ALL calculations. 1. Carbamide (CH4N2O), can be synthesized by the reaction of ammonia (NH3) with carbon dioxide (CO2): 2 NH3 (aq) + CO2 (aq) CH4N2O (aq) + H2O (l) An industrial synthesis of urea obtains 87.5 kg of urea upon reaction of 68.2 kg of ammonia with 105 kg of carbon dioxide. Determine the limiting reactant, theoretical yield of urea and percent yield for the reaction.

4 2. Sodium bicarbonate is often used as an antacid to neutralize excess hydrochloric acid in an upset stomach. How much hydrochloric acid in grams can be neutralized by 3.5 g of sodium bicarbonate?

5 3. Explain what is wrong with each electron configuration and write the correct ground state configuration based on the number of electrons. State which element is represented by the corrected electron configuration. a. 1s 3 2s 3 2p 9 b. 1s 2 2s 2 2p 6 2d 4 c. 1s 2 1p 5 END OF QUESTIONS

6 CHM1025 Exam 4 Chapters 9, 10, & 13 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A sample of 8.5 g NH 3 on oxidation produces 4.5 g of NO. Calculate the percent yield. Reaction: 4 NH O 2 4 NO + 6 H 2 O A) 15 % B) 30% C) 60% D) 70% 2) How many grams of NO2 are theoretically produced if we start with 1.20 moles of S and 9.90 moles of HNO3? Reaction: S + 6HNO3 H2SO4 + 6NO2 + 2H2O A) 455 B) 786 C) 7.20 D) 331 1) 2) 3) Which of the following atoms has the least metallic character? 3) A) Na B) K C) Li D) Cs E) Rb 4) Consider the following generic chemical equation: 2W + 3X 3Y + Z When 5 units of W and 6 units of X are allowed to react, the limiting reactant would be: A) X B) W C) Z D) Y E) There is no limiting reactant in this situation. 4) 5) How are wavelength and frequency of light related? 5) A) Wavelength increases as the frequency decreases. B) Wavelength is independent of frequency. C) Wavelength increases as frequency increases. D) Wavelength is double the frequency. E) Wavelength is one-half of the frequency. 6) Which one of the following is the correct orbital diagram for nitrogen? 6) A) B) C) D) 7) In order to to determine the limiting reactant in a particular reaction, one must know each of the following EXCEPT A) the molar mass of each reactant present B) the coefficient of each reactant in a balanced equation C) the mass of each product formed 7)

7 D) the mass of each reactant present 8) What is the correct order of the electromagnetic spectrum from shortest wavelength to longest? 8) A) Gamma Rays X-rays Infrared Radiation Visible Light Ultraviolet B) Visible Light Infrared Gamma Rays X-rays Ultraviolet Radiation C) Radio Waves X-rays Ultraviolet Radiation Visible Light Infrared Radiation Microwaves Gamma Rays D) Gamma Rays X-rays Ultraviolet Radiation Visible Light Infrared E) Gamma Rays X-rays Visible Light Ultraviolet Radiation Infrared 9) What is the theoretical yield of a reaction if 25.0 grams of product were actually produced from a reaction that has a 88% yield? A) 28.4 B) 22.0 C) 3.52 D) ) Which one of the following species has the electron configuration of 1s22s22p6? 1. Na+ 2. O2-3. F- A) 1 and 2 only B) 2 and 3 only C) 1 and 3 only D) All of 1, 2, and 3 E) Neither 1, 2, or 3 9) 10) 11) Which of the following elements has the highest ionization energy? 11) A) Ca B) Ba C) Ne D) Cl E) Al 12) What is the percent yield of CuS for the following reaction given that you start with of Na 2 S and CuSO 4? The actually amount of CuS produced was. Reaction: Na 2 S + CuSO 4 Na 2 SO 4 + CuS A) 16.1% B) 42.1% C) 18.93% D) 7.25% 12) 13) The n = principal shell is the lowest that may contain a d-subshell. 13) A) 3 B) 2 C) 4 D) 1

8 14) "When filling orbitals of equal energy, electrons fill them singly first with parallel spins." This is known as: A) Pauli exclusion principle B) Bohr's model C) Ground state D) Hund's rule 15) What is the excess reactant for the reaction below given that you start with 10.0 g of Al and of O 2? Reaction: 4Al + 3O 2 2Al 2 O 3 A) Al 2 O 3 B) Al C) O 2 D) both Al and O 2 14) 15) 16) What do the alkali metals all have in common? 16) A) They all undergo similar reactions. B) They all have similar physical properties. C) They all have the same number of valence electrons. D) They all form +1 ions. E) all of the above 17) Given that 4 NH O 2 4 NO + 6 H 2 O, if 3.00 mol NH 3 were made to react with excess of oxygen gas, the amount of H 2 O formed would be, A) 3.00 mol B) 6.00 mol C) 4.50 mol D) 2.00 mol 17) 18) Which of the following statements is false? 18) A) The actual yield is the amount of product actually produced by a chemical reaction. B) The percent yield = x 100% C) The theoretical yield is the amount of product that can be made based on the amount of limiting reagent. D) The limiting reactant is completely consumed in a chemical reaction. E) All of the above are true statements. 19) When sunlight is passed through a prism, what is observed? 19) A) white light B) continuous spectrum C) bright spots and lines D) nothing 20) What is the limiting reactant for the following reaction given we have 3.4 moles of Ca(NO 3 ) 2 and 2.4 moles of Li 3 PO 4? Reaction: 3Ca(NO 3 ) 2 + 2Li 3 PO 4 6LiNO 3 + Ca 3 (PO 4 ) 2 20)

9 A) LiNO 3 B) Ca(NO 3 ) 2 C) Ca 3 (PO 4 ) 2 D) Li 3 PO 4

10 1) B 2) D 3) C 4) A 5) A 6) B 7) C 8) D 9) A 10) D 11) C 12) B 13) A 14) D 15) C 16) E 17) C 18) E 19) B 20) B