AP ChemistryName :
Worksheet : 3-4Date :
A. No calculator review :
_____ 1. A metal which can be used to block radiation and is very dense.
_____ 2. A monovalent metal which is valuable and forms precipitates with halides.
_____ 3. A metal which tends to form 2+ ions and 4+ ions and is colored in solution
_____ 4. A bivalent metal which is colorless in solution. Can be used to protect less reactive metals such as iron.
_____ 5. A bivalent metal which can react with water to form a base under high temperature conditions.
_____ 6. liquid at room temperature
_____ 7. gas at room temperature
_____ 8. solid at room temperature
_____ 9. diatomic
_____ 10. yellow-green gas, toxic, with a strong odor
_____ 11. Strong oxidizer, soluble, purple in color
_____ 12. Insoluble pale-bluish compound
_____ 13. soluble compound, white solid
_____ 14. yellow, insoluble compound, toxic
_____ 15. The atomic mass of element X is 52.75. Given that there are only two isotopes of element X, 54X and 52X, what is the abundance of 52X?
a. 25%b. 38%c. 50.%d. 63%e. 75%
_____ 16. How many moles of water are there in 27 g of water?
a. 0.67 molb. 1.0 molc. 1.3 mold. 1.5 mole. 1.7 mol
_____ 17. For which of the following compounds does 0.753 mol weigh 77g?
a. C2H7O2Nb. C3H8c. Al2O3d. C8H20e. ZnO
2NO + O2 2NO2
_____ 18. Given the above reaction, how many grams of nitrogen dioxide can be formed from 15 grams of nitrogen monoxide and 20. grams of oxygen?
a. 6.0 gb. 12 gc. 23 gd. 29 ge. 46 g
_____ 19. A compound contains 48 g of carbon, 16 grams of hydrogen and 32 g of oxygen, what is the empirical formula of this compound?
a. C2H4Ob. C4H4Oc. CH2Od. C2H6Oe. C2H8O
_____ 20. Calcium-37 contains
a. 37 protons, 37 neutrons and 37 electronsd. 20 protons, 17 neutrons and 20 electrons
b. 20 protons, 17 neutrons and 17 electronse. 18 protons, 19 neutrons and 18 electrons
c. 17 protons, 20 neutrons and 17 electrons
21. Natural rubidium has the average mass 85.4678 and is composed of isotopes 85Rb (mass = 84.9117) and 87Rb. The ratio of atoms 85Rb/87Rb in natural rubidium is 2.591. Calculate the mass of 87Rb. (Hint calculate % 85Rb and 87Rb first).
22. A compound contains only carbon, hydrogen, nitrogen, and oxygen. Combustion of 0.157 g of the compound produced 0.213 g CO2 and 0.0310 g H2O. In another experiment, it is found that 0.103 g of the compound produces 0.0230 g NH3. What is the empirical formula of the compound? Hint: Combustion involves reacting with excess O2. Assume that all the carbon ends up in CO2 and all the hydrogen ends up in H2O. Also assume that all the nitrogen ends up in the NH3 in the second experiment.(Hint :Use mass percent of N from second exp. to get mass and moles of N in first exp.. Subtract to get mass and mol of O).
23. The production capacity for acrylonitrile (C3H3N) in the United States is over 2 billion pounds per year. Acrylonitrile, the building block for polyacrylonitrile fibers and a variety of plastics, is produced from gaseous propylene, ammonia, and oxygen:
2C3H6(g) + 2NH3(g) + 3O2(g) 2C3H3N(g) + 6H2O(g)
a. Assuming 100% yield, what mass of acrylonitrile can be produced from a mixture of 5.00 x 102 g propylene, 5.00 x 102 g ammonia, and 1.00 x 103 g oxygen?
b. What mass of water is produced, and what masses of which starting materials are left in excess?
24. An element X forms both a dichloride (XCl2) and a tetra-chloride (XC14). Treatment of 10.00 g XC12 with excess chlorine forms 12.55 g XCl4. Calculate the atomic mass of X, and identify X.
25. A salt contains only barium and one of the halide ions. A 0.158-g sample of the salt was dissolved in water, and an excess of sulfuric acid was added to form barium sulfate (BaSO4), which was filtered, dried, and weighed. Its mass was found to be 0.124 g. What is the formula of the barium halide?
26. A 1.500-g sample of a mixture containing only Cu2O and CuO was treated with hydrogen to produce 1.252 g pure copper metal. Calculate the percentage composition (by mass) of the mixture.
Answers : 1.b 2. c 3.d 4.a 5.e 6.c 7.f 8.d 9.e 10.b 11.c 12.b 13.d 14.a 15.d 16.d 17.c 18.c 19.e 20.d 21. 86.91 amu 22. C7H5N3O6 23a. 631 g C3H3N 23b. 643 g H2O, 430 g O2 left, 297 g NH3 left 24. Pb 25. BaBr2 26. 60.% CuO, 40.% Cu2O
AP Chemistry-ws-3-4