1) 3.5x10 3 g sucrose 2) 1.1x10 3 g sucrose 3) 3.5 g sucrose 4) 4.4x10 3 g sucrose 5) 4.5 g sucrose

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1 Form Code X NAME CHM 2045, Fall 2015, Exam 1 Review Packet (Broward Teaching Center) Final Packet Instructions: Do your best and don t be anxious. Read the question, re-read the question, write down all given or valuable information, and write down what you want to find. As on all graded events, the loving of moles applies. 1. A solution of sucrose in water is 55.0% sucrose by mass and has a density of 1.59 g/ml. What mass of sucrose, in grams, is contained in 4.00 L of solution? 1) 3.5x10 3 g sucrose 2) 1.1x10 3 g sucrose 3) 3.5 g sucrose 4) 4.4x10 3 g sucrose 5) 4.5 g sucrose 2. The compound (X) contains % carbon, % hydrogen, % nitrogen, and 16.48% oxygen by mass. Additionally, X s molecular weight lies between the domain of Compound Y s MW and Compound Z s MW. If MWY = 188 g/mol and MWZ = 200 g/mol. Determine the molecular formula of the compound. 1) C4H5N2O 2) C8H10N4O2 3) C8H8N3O3 4) C10H7N5O2 5) C8H10N2O

2 3. The radioactive 50 V isotope has which Z, neutron number, and A (respectively)? 1) 23, 23, 27 2) 35, 27, 50 3) 23, 27, 50 4) 20, 81, 35 5) 35, 27, If g BaCl2 xh2o yields g of anhydrous BaSO4 ( g/mol) after treatment with excess sulfuric acid, what is the value of x in the formula of BaCl2 xh2o? (round to nearest whole number) 1) one 2) two 3) three 4) four 5) five

3 5. Calculate the number of oxygen atoms in g of sodium sulfate, Na2SO4. (1) x O atoms (2) x O atoms (3) x O atoms (4) x O atoms (5) x O atoms 6. If 4.00 g of element G reacts with 7.00 g of element M to produce g of a compound with the formula G3M4, and the atomic mass of M is amu, what is the atomic mass of G? 1) 60.5 amu 2) amu 3) 72.0 amu 4) 89.5 amu 5) 150 amu

4 7. Consider the following reaction: 2A + B 3C + D If 3.0 mol A and 2.0 mol B react to form 4.0 mol C. What is the percent yield of this reaction? (1) 100% (2) 67% (3) 89% (4) 50% (5) 75% 8. If a sheet of aluminum foil (d = 2.70 g/cm3) weighs 6.45 lbs and is mm thick, the surface area of the foil is closest to? 1) 9.40 ft 2 2) 13.9 ft 2 3) 234 ft 2 4) 740 ft 2 5) 555 ft 2

5 9. Which of the following ionic compounds/names are true? A) Magnesium Dicholride B) Fe2O3 C) Iron (III) Oxide D) NH3 1) A, B, C, D 2) A only 3) A and B only 4) B and C only 5) D only 10. Which of the covalent compounds are incorrect? A) P4S5 (tetraphosphorous pentasulfur) B) Si2Br6 (disilicon hexabromide) C) ClO2 (monochorine dioxide) 1) A only 2) B and C only 3) C only 4) B and C only 5) A and C only 11. Which of the following is false? 1) Iron(III) sulfide has three Fe atoms 2) HCl is a strong acid 3) Z is the atomic number symbol 4) N2O3 is dinitrogen trioxide 5) The reaction H2(g) + F2(g) 2HF(g) is a redox reaction

6 12. Which of the following is closest to the mass of chromium in g Cr2O3? 1) g 2) g 3) g 4) g 5) g 13. Sweetener saccharin (C7H5NO3S) is sometimes dispensed in tablet form. Ten (10) tablets with a total mass of g were dissolved in water. They were oxidized to convert all the sulfur to sulfate ion, which was precipitated by adding an excess of barium chloride solution. The mass of barium sulfate obtained was g. What is the average mass percent of saccharin in the tablets? Hint* Think of a pregnant mole.literally! 1) 69% 2) 40% 3) 65% 4) 39.4% 5) 58.94% 14. Given the reaction: 3 H2S + 2 FeCl3 Fe2S3 + 6 HCl We have 60.0 g of FeCl3 reacts with 42.0 g of H2S. Which is the limiting reactant. Also, what is the percent yield given that only 36g of HCl is produced? 1) 88.76% 2) 70% 3) 36% 4) 89.91% 5) 62%

7 15. Both Mg3N2 (100.9 g/mol) and Mg(OH)2 (58.3 g/mol) can be converted to MgO (40.3 g/mol) by appropriate means. If a 2.00 g mixture of these two compounds is converted, and 1.50 g of MgO is obtained, what is the approximate mass percent of Mg3N2 in the mixture? (1) 11.5% (2) 20% (3) 50% (4) 10% (5) 96% 16. The concentration of LiOH is 0.50 M. If 25 ml of LiOH is needed to titrate 40 ml of HNO3 (nitric acid) what is the concentraiton of HNO3? 1) M HNO3 2) 0.8 M HNO3 3) M HNO3 4) 0.08 M HNO3 5) 1.00 M HNO3

8 17. Select the false statement below: (1) Pb 2+( aq) + 2I (aq) PbI2(s) is a precipitation reaction but is not a redox reaction (2) CH4(g) + 2O2(g) CO2(g) + 2H2O(g) is a combustion reaction and a redox reaction (3) Ca(s) + F2(g) CaF2(s) is a precipitation reaction and a redox reaction (4) HNO3(aq) + KOH(aq) H2O(l) + KNO3(aq) is an acid-base reaction but is not a redox reaction (5) H2SO4(aq) + Ba(OH)2(aq) 2H2O(l) + BaSO4(s) is a precipitation reaction and an acidbase reaction 18. In which of the following equations are the base and conjugate base (proposed bases are underlined) incorrectly labeled? (1) HCl + H2O Cl - + H3O + (2) H2PO4 - + H2O H3PO4 + OH - (3) CN - + H2O HCN + OH - (4) CH3COOH + H2O CH3COO - + H3O + (5) HCO3 - + H2O H2CO3 + OH In which of the following equations are the acid and conjugate acid (proposed bases are underlined) correctly labeled? 1) CH3CO2H(aq) + H2O(l) <-----> H3O + (aq) + CH3CO2 -( aq) 2) NH3(g) + H2O(l) NH4 + (aq) + OH (aq) 3) HCl + NH3 NH4 + + Cl - 4) H3O + + OH - 2H2O 5) H2NO2 + H2O NO2 - + H3O How many hydrogen ions are present in a 14.6 ml aqueous solution of sulfurous acid given that density Sulfurous acid = 1.03g/mL. 1) 1.1x10 23 H+ ions 2) H+ ions 3) 2.207x10 23 H+ ions 4) 2.22x ) 2.21x10 22 H+ ions

9 21. Find the percent by mass of hydrogen in ammonium hypochlorite? 1) 5.76% 2) 3.49% 3) 7.66% 4) 4.05% 5) 50% 22. How many mols of Aluminum are in 268.9g Aluminum Oxide? 1) 2.64 mol Al 2) 3.45 mol Al 3) 5.27 mol Al 4) 1 mol Al 5) mol Al

10 23. If 20.00g of Calcium Carbonate reacts with Magnesium Nitrate in a double displacement reaction, how many mols of nitrate is produced through the reaction? Assume that reaction goes to completion and that there is no excess of reactants. Hint* What is the charge of Nitrate? Hint*This is a double displacement Hint*Write out the reaction 1) 0.4 mols Nitrate 2) 0.8 mols Nitrate 3) 1.2 mols Nitrate 4) 1.0 mols Nitrate 5) 4.5 mols Nitrate 24. How many grams of sodium are needed to make a 750 ml of a 1.3 M solution of sodium bromide? Hint* Write out what the units of molarity are. Hint* What does multiplying molarity by volume leave you with? 1) g Sodium 2) 85.43g Sodium 3) 1.73g Sodium 4) g Sodium 5) 80.00g Sodium

11 25. How many chromium ions are in 63.54g of potassium chromate? Hint* What is Chromate? Hint*What is Potassium s oxidation number? Hint*Think of pregnant moles.literally.again!! Hint* Molar mass of Potassium Chromate = 194.2g/mol 1) 0.327x10^23 2) ) ) 2.00x10^23 5) 1.97x10^23 GOOD LUCK and SMILE ON THE EXAM!!! -Broward Teaching Center