1. Borax is Na2[B4O7]10H2O.
What is the mass percent of water in borax?
How many pounds of borax contain 5.00 lb boron?
2. If you were interested only in the mass of the metal contained,
which compound would be the cheapest source of gold:
AuI at $75.00 per 5g or Au2O3 at $25.00 per g.
?
3. A 4.60-mg sample of a new enzyme found to contain manganese was treated
with a strong oxidizing agent and all of the Mn was converted to potassium
permanganate. The mass of KMnO4 obtained was 2.75µg.
What is the percent of Mn in the enzyme?
If there is only one Mn atom in each enzyme molecule, what is the molecular
weight of the enzyme?
4. What is the mass of 15 nmol of tetraphosphorus heptasulfide?
5. The pale yellow liquid, nicotine, is a compound containing 74.03% C, 8.70% H, and 17.27% N. Determine the empirical formula of nicotine.
6. How many grams of carbon are contained in 5.00 mL bromoform (CHBr3), a liquid with density 2.9035 g.mL-1?
7. Ca(MnO4)2 + 16 HBr -->5 Br2 + CaBr2 +2 MnBr2 + 8 H2O
How many grams of Ca(MnO4)2 are needed to produce 5.00 g Br2?
8. What mass of SO2 is produced when 16.25 g thiophen, C5H5S, is burned in excess oxygen?
9. A solution containing 5.00 g AgNO3 is mixed with a solution containing 12.50 g CaCl2. A white precipitate of AgCl is formed. What is the mass of the AgCl formed? Which is the limiting reagent, AgNO3 or CaCl2?
10. Which of the following are intensive properties of a substance?
Color, mass, volume, electrical conductivity
11 Name the following : Ca3N2, Pb(ClO)2, S2Cl2, OF2, Mn(MnO4)2
12. Write formulas for the following
magnesium chlorate, ferrous chloride, mercurous nitrate, diboron hexahydride,
bromine pentafluoride
13. For each of the following provide the number of protons and neutrons in the nucleus, and the number of electrons surrounding the nucleus. (Periodic Table available)
Si, Sc, Se2-, Sr2+, Sb3+, an alpha-particle
14. Describe the experiment that led to the conclusion that atoms contain a very small nucleus with most of the atomic mass. With which scientist is this experiment associated?
15. How may alpha-, beta-, and gamma-radiation be distinguished experimentally?
16. You are given a white powder in the laboratory. Describe three experiments that you could carry out to determine whether the powder was a mixture or a pure substance.
17. Define "mole", "density", and "isotopes"
18. Write a chemical formula that illustrates each of the following:
a binary molecular compound
a polyatomic cation
an electrolyte
19. Write and balance chemical equations for the following reactions
(A) combustion of powdered aluminum metal in chlorine gas
(B) the direct combination of lead with sulfur
(C) the decomposition of cupric nitrate to form copper(I) oxide, nitrogen dioxide, and oxygen gas
(D) the combustion of dimethylsulfoxide (CH3)2SO in oxygen
(E) the decomposition of ammonium nitrite to form water and nitrogen gas
20. Write formulas for:
mercury(I) carbonate; diphosphorus tetrahydride; octasulfur; chromic
cyanide; sodium peroxide; aluminum nitride; permanganic acid
21. Name the following:
HClO2; Al4C3; NaIO4; As2O3;
NiSO3; H2Se
22. Calculate the atomic weight of silicon from the following
isotopic masses and abundances:
28Si (92.28%) 27.9866; 29Si (4.67%) 28.9866,
30Si (3.05%) 29.9832
23. A 4.000-g sample of a phosphorus sulfide was burned in oxygen, and the products reacted with calcium hydroxide to form 17.819 g of a mixture of solid Ca3(PO4)2 and CaSO3. Addition of hydrochloric acid caused the calcium sulfite to dissolve leaving 11.273 g of calcium phosphate. Determine the empirical formula of the phosphorus sulfide.
24. (A) What is the mass of solute in 345 mL of 2.20 M NiCl2?
(B) A 50.0% solution of sulfuric acid (50 g H2SO4,
50 g water) has a density of 1.395 g/mL. What is the molarity of this solution?
(C) When sodium metal reacts with water, H2 is evolved and
a solution of NaOH is formed. What is the molarity of NaOH produced when
4.6 g Na metal is dissolved in water, and the final volume of the solution
is made up to 500.0 mL?
25. PbO2 + 4HI ---> I2 + PbI2
+ 2H2O
How many millimoles of I2 are produced when 10.0
g PbO2 are heated with 150 mL of 4.00 M HI?
26. Calcium hypochlorite is a strong electrolyte but hypochlorous acid is a weak electrolyte. Write chemical equations that show what occurs when these two substances dissolve in water.