CHEM 131 Instructor: Maxi Boeckl
Your Name: ______
REVIEW PROBLEM SET
1 Classify the following properties as physical or chemical.
a) Iron melts at 1535°C; ______
b) Alcohol is very flammable; ______
c) The metal used in artificial hip joint implants is not corroded by body fluids; ______
d) A 1 in. cube of aluminum weighs less than a 1 in. cube of lead; ______
e) An antacid neutralizes stomach acid; ______
2 Classify each of the following as homogeneous or heterogeneous.
a) muddy flood water ______
b) normal urine ______
c) smog-filled air ______
d) mouthwash ______
e) petroleum jelly ______
3 Classify each of the following as an element, compound or mixture:
a) Blood; ______
b) Water; ______
c) Oxygen; ______
d) Air ______
4 Determine the number of protons, number of neutrons, and number of electrons in atoms of the following isotopes. For each one write down the mass number and the atomic number.
5 Which of the following carries a negative charge?
a. / a proton / c. / an electronb. / a neutron / d. / both proton and neutron
6 Determine the molecular weights of the following in u. What other unit can molecular weights be expressed as?
a) sodium hydroxide, NaOH; b) ethyl alcohol (C2H6O)
7 Perform the following calculations:
a) If Beryllium has a molecular weight of 9.012 g/mol, determine the number of moles of beryllium atoms in a 25.0-g sample of beryllium.
b) Determine the number of lead atoms in a 1.68-mol sample of lead (MW = 207.2 g/mol).
8 Which of the following elements is a nonmetal?
a. / Ni / b. / Cu / c. / Ba / d. / I9 Which of the following is a noble gas?
a. / gold / b. / platinum / c. / neon / d. / chlorine10 Draw Lewis dot structures for the following elements and compounds:
a) iodine b) HF c) phosphorus d) PH3 (each H atom is bonded to the P atom)
11 Write formulas for the following binary ionic compounds:
a) iron(II) bromide b) iron(III) sulfide c) chromium(II) oxide
12 Use the periodic table and Table 4.3 or Fig 3-10 to determine which of the following bonds will be polarized. Show the resulting charge distribution (partial charges) in those molecules that contain polarized bonds.
13 In describing the strength of intermolecular forces, we discover that the weakest forces of bonds are
a. / covalent / b. / metallic / c. / dipolar / d. / dispersion14 Which type of intermolecular forces leads to compounds with the lowest melting points?
a. covalent b. dispersion forces c. ionic d. dipolar forces
15 Which of the following correctly illustrates hydrogen bonding in water?
a. b. c. d.
16 A covalent bond results when
a. / one atom gives up an electron to another atomb. / one atom gives up two electrons to another atom
c. / two atoms share a pair of electrons
d. / two atoms share a single electron
17 Fill in the missing parts in the following table:
Element / Symbol / Number of valence electrons / Number of bonds that can be formedCarbon / C / 4 / 4
H
Oxygen
Br
Sulfur
Nitrogen
Na
Aluminum
Ar
18 A sample of 4.00 g of methane (CH4) is mixed with 15.0 g of chlorine (Cl2).
a) Determine which is the limiting reactant according to the following equation:
CH4(g) + 4Cl2(g) → CCl4(l) + 4HCl(g)
b) What is the maximum mass of CCl4 that could be formed?
c) What is the percent yield if 2.4 g of CCl4 is formed?
19 High density is characteristic of which state of matter?
a. solid b. liquid c. gaseous d. more than one response is correct
20 Use the terms soluble, insoluble, or immiscible to describe the behavior of the following pairs of substances when shaken together:
a) 25 mL of water and 1 g of salt-the resulting mixture is clear and colorless.______
b) 25 mL of water and 1 g of solid silver chloride-the resulting mixture is cloudy and the solid settles out. ______
c) 25 mL of water and 5 mL of mineral oil-the resulting mixture is cloudy and gradually separates into two layers. ______
21 Indicate which of the following substances (with geometries shown in the text) would be soluble in water (a polar solvent) and in benzene (a nonpolar solvent):
a) b) c)
22 Calculate the following the molarity (M) of 500 mL of solution that contains 0.304 mol of solute.
23 Using Le Châtelier’s principle, predict the direction of equilibrium shift and the changes that would be observed (color, amount of precipitate, etc.) in the following equilibria when the indicated stress is applied:
24 Write the dissociation equations for the following that emphasize their behavior as Arrhenius acids or bases:
a) HI b) KOH c) HClO2 d) Sr(OH)2
25 Identify each acid and base and their conjugate acid and base in the following equations. Note that the reactions are assumed to be reversible.
a) HBr(aq) + H2O (aq) « H3O+(aq) + Br -(aq)
b) H2SO4(aq) + H2O(l) « H3O+(aq) + HSO4-(aq)
c) NH3(aq) + H2O(l) « NH4+(aq) + OH-(aq)
26 Determine the pH of water solutions with the following characteristics. Classify each solution as acidic, basic, or neutral.
a) [H+] = 3.7 x10-4 M b) [OH-] = 1.3 x10-1 M
27 You need to prepare 500 mL of a 0.10M HCl(aq) solution. All you have is a 2.0M HCl(aq) solution in the lab. What do you need to do?