Chemistry 1411 Final Exam: Top-Tier Questions & Expert Solutions, Exams of Chemistry

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Chemistry 1411 Final Exam: Top-Tier Questions &

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You have 75.0 mL of a 2.50 M solution of NaCrO4(aq). You also have 125 mL of a 2.26 M solution of AgNO3(aq). Calculate the concentration of NO3- after the two solutions are mixed together. A. 0.00 M B. 0.706 M C. 1.41 M D. 2.82 M E. 4.50 M - CORRECT ANS- - Consider the following portion of the energy-level diagram for hydrogen: n = 4 - 0.1361 x 10 ^-18 J n = 3 - 0.2420 x 10 ^-18 J n = 2 - 0.5445 x 10 ^-18 J n = 1 - 2.178 x 10 ^-18 J For which of the following transitions does the light emitted have the longest wavelength? A. n = 4 to n = 3 B. n = 4 to n = 2 C. n = 4 to n = 1 D. n = 3 to n = 2 E. n = 2 to n = 1

Consider an aqueous solution of calcium nitrate added to an aqueous solution of sodium phosphate. Write and balance the equation for this reaction to answer the following question. What is the sum of the coefficients when the molecular equation is balanced in standard form? A. 4 B. 5 C. 7 D. 11 E. 12 - CORRECT ANS- - The following statements concerning petroleum are all true except: A. it is a thick, dark liquid composed mostly of hydrocarbons. B. it must be separated into fractions (by boiling) in order to be used efficiently. C. some of the commercial uses of petroleum fractions include gasoline and kerosene. D. it was probably formed from the remains of ancient marine organisms. E. all of its hydrocarbon chains contain the same number of carbon atoms. Aqueous solutions of sodium sulfide and copper(II) chloride are mixed together. Which statement is correct? A. Both NaCl and CuS precipitate from solution. B. No reaction will occur. C. CuS will precipitate from solution. D. NaCl will precipitate from solution.

Which of the following statements are true? I. The electrons in each molecule tend to orient themselves around the most electronegative element. II. Each molecular drawing follows the localized electron model. III. Both HF and CO2 are linear molecules and therefore polar. IV. The bond angles of NH3 are slightly less than 109.5° because the lone pair compresses the angles between the bonding pairs. A. I, III, IV B. I, II, IV C. I, II, III D. II, IV E. All of the above statements are correct. Which of the following statements is least likely to be true of a sample of nitrogen gas? A. Molecules of gaseous nitrogen are in constant random motion. B. The pressure exerted by gaseous nitrogen is due to collisions of the molecules with the walls of the container. C. The average kinetic energy of the gaseous nitrogen is proportional to the absolute temperature of the gas. D. Collisions between the gaseous molecules are elastic. E. The volume of the sample would be zero at - 273°C. - CORRECT ANS- - Consider the following portion of the energy-level diagram for hydrogen: n= 4 - 0.1361 x 10^-18 J

n= 3 - 0.2420 x 10^-18 J n= 2 - 0.5445 x 10^-18 J n= 1 - 2.178 x 10^-18 J In the hydrogen spectrum, what is the wavelength of light associated with the n= X to n= 1 electron transition? A. 1.99 x 10^-25 nm B. 3.65 x 10^2 nm C. 8.22 x 10^6 cm D. 1.63 x 10^-18 m E. 1.22 x 10^-7 m An oxide of iron has the formula Fe3O4. What mass percent of iron does it contain? A. 0.72% B. 28% C. 30% D. 70% E. 72% - CORRECT ANS- - Which of the following reactions does not involve oxidation-reduction? A. CH4 + 3O2 → 2H2O + CO B. Zn + 2HCl → ZnCl2 + H C. 2Na + 2H2O → 2NaOH + H D. MnO2 + 4HCl → Cl2 + 2H2O + MnCl

If each tonne of coal produces 1.30 × 10^4 L of sulfur dioxide (measured at STP), what mass of sulfuric acid can result from combustion of each tonne of coal? (1 tonne = 1000 kg) A. 2.85 x 10^1 kg H2SO B. 2.86 x 10^4 kg H2SO C. 5.69 x 10^7 kg H2SO D. 5.69 x 10^1 kg H2SO E. 1.14 x x 10^2 kg H2SO4 - CORRECT ANS- - Which of the following statements about the CO3^2- ion is false? A. The orbitals on the carbon atom are sp2 hybridized. B. The ion is expected to be diamagnetic. C. The C-O bonds are different lengths. D. The ion has a total of 24 electrons. E. All the above statements are true. The hybridization of the central atom in XeF5+ is: A. sp B. sp C. sp D. dsp E. d2sp3 - CORRECT ANS- - Consider three 1-L flasks at STP. Flask A contains NH3 gas, flask B contains NO2 gas, and flask C contains N2 gas. In which flask are the molecules least polar and therefore most ideal in behavior? A. Flask A

B. Flask B C. Flask C D. All are the same. E. More information is needed to answer this. A balloon has a volume of 2.68 liters at 24.0°C. The balloon is heated to 48.0°C. Calculate the new volume of the balloon. A. 2.68 L B. 2.90 L C. 2.48 L D. 5.36 L E. 1.34 L - CORRECT ANS- - Which of the following molecules is nonlinear? NO2- , C2H2 , N3- , HCN , CO2 , H2O A. C2H2, HCN B. CO2, N3- C. NO2-, H2O D. N3-, NO2- E. All are linear Aqueous solutions of barium chloride and silver nitrate are mixed to form solid silver chloride and aqueous barium nitrate. The balanced molecular equation contains which one of the following terms?

D. NO3- , K+ , CrO4^2 , water E. water Which of the following equations is not balanced? A. 4Al + 3O2 → 2Al2O B. C2H6 + 7/2 O2 → 2CO2 + 3H C. 2KClO3 → 2KCl + 3/2 O D. 4P4 + 5S8 → 4P4S E. P4 + 5O2 → P4O10 - CORRECT ANS- - Suppose the reaction Ca3(PO4)2 + 3H2SO4 → 3CaSO4 + 2H3PO4 is carried out starting with 155 g of Ca3(PO4)2 and 81.3 g of H2SO4. how much phosphoric acid will be produced? A. 81.2 g B. 54.1 g C. 236.3 g D. 121.8 g E. 97.9 g What volume of carbon dioxide measured at STP will be formed by the reaction of 1.43 mol of oxygen with 0.900 mol of ethyl alcohol, CH3CH2OH? A. 40.3 mL B. 21.4 L C. 32.0 L D. 48.0 L E. 0.953 L - CORRECT ANS- - Tetracyanoethylene has the skeleton shown below:

From its Lewis structure determine the following: How many of the atoms are sp2 hybridized? A. 2 B. 4 C. 6 D. 8 E. 10 Calcium hydride combines with water according to the equation: CaH2(s) + 2H2O(l) → 2H2(g) + Ca(OH)2(s) Beginning with 84.0 g of CaH2 and 42.0 g of H2O, what volume of H2 will be produced at 273 K and a pressure of 1482 torr? A. 26.8 L B. 13.4 L C. 4.83 x 10^2 L D. 23.0 L

B. SiCl C. NF D. F E. None of these Which of the nitrogen-containing molecules below is paramagnetic in its lowest energy state? A. N B. NO C. NH D. N2H E. None of these - CORRECT ANS- - Exactly 277.7 J will raise the temperature of 10.0 g of a metal from 25.0°C to 60.0°C. What is the specific heat capacity of the metal? A. 1.26 J/g°C B. 0.793 J/g°C C. 11.1 J/g°C D. 66.4 J/g°C E. none of these The following two reactions are important in the blast furnace production of iron metal from iron ore (Fe2O3):

Using these balanced reactions, how many moles of O2 are required for the production of 6.51 kg of Fe? A. 87.4 moles B. 38.9 moles C. 350 moles D. 116.6 moles E. 4.88 moles - CORRECT ANS- - How many grams of potassium are in 15.0g of K2CrO7? A. 2.42 g B. 0.767 g C. 4.84 g D. 78.2 g E. 30.0 g Which of the following species has a trigonal bipyramid structure? A. NH B. IF C. I3- D. PCl E. none of these - CORRECT ANS- - Given the equation:

If all of the chloride in a 4.519-g sample of an unknown metal chloride is precipitated as AgCl with 70.90 mL of 0.2010 M AgNO3, what is the percentage of chloride in the sample? A. 50.52% B. 11.18% C. 1.425% D. 8.945% E. none of the above - CORRECT ANS- - How many moles of hydrogen sulfide are contained in a 39.3-g sample of this gas? A. 0.867 mol B. 1.15 mol C. 73.4 mol D. 19.5 mol E. 2.31 mol Using the following data reactions: ΔH° (kJ) H2(g) + Cl2(g) → 2HCl(g) - 184 H2(g) → 2H(g) 432 Cl2(g) → 2Cl(g) 239 Calculate the energy of an H-Cl bond. A. 855 kJ B. 244 kJ

C. 487 kJ D. 92 kJ E. 428 kJ - CORRECT ANS- - Consider the molecule and the following hybridization choices: What is the hybridization of the carbon atom that is bonded to chlorine? A. sp B. sp C. sp D. dsp E. d2sp The man who discovered the essential nature of acids through solution conductivity studies is _____. A. Priestly B. Boyle C. Einstein D. Mendeleev

E. observation e What mass of calcium chloride, CaCl2, is needed to prepare 3.350 L of a 1.57 M solution? A. 237 g B. 5.26 g C. 52.0 g D. 111 g E. 584 g - CORRECT ANS- - When electrons in a molecule are not found between a pair of atoms but move throughout the molecule, this is called _____. A. ionic bonding B. covalent bonding C. polar covalent bonding D. delocalization of the electrons E. a dipole moment An unknown substance dissolves readily in water but not in benzene (a nonpolar solvent). Molecules of what type are present in the substance? A. Neither polar nor nonpolar B. Polar C. Either polar or nonpolar D. Nonpolar E. None of these - CORRECT ANS- - The hybridization of Br in BrF3 is:

A. sp B. sp C. sp D. dsp E. d2sp In the molecular orbital description of CO: A. the highest energy electrons occupy antibonding orbitals. B. six molecular orbitals contain electrons. C. there are two unpaired electrons. D. the bond order is 3. E. all of the above are false. - CORRECT ANS- - Nitric acid, HNO3, contains what percent hydrogen by mass? A. 3.25% B. 20.0% C. 25.4% D. 1.60% E. 2.22% For which of the following elements does the electron configuration for the lowest energy state show a partially filled d orbital? A. Ti