Supplemental Instruction
Iowa State University / Leader: / Nevin
Course: / Chem 177
Instructor: / Kingston
Date: / 09/22/13
1) Which of the following is NOT a chemical reaction?
a) Dissolution of penny in nitric acid
b) Burning of a candle
c) The melting of copper
d) Formation of polyethylene from ethylene
2) What are intensive and extensive properties? Give an example of each.
Intensive doesn’t depend on mass, but extensive do. Example of intensive would be density, example of extensive would be mass or volume.
3) You are running an experiment to determine the amount of carbon in a 10g of a liquid. The accepted value of carbons is 5g. Label each of the following a certain level of accuracy and precision. (good or bad)
- 4.0g, 1.9g, 9.9g, 8.3g bad precision, bad accuracy
- 3.3g, 3.2g, 3.0g, 3.2g good precision, bad accuracy
- 5.1g, 5.0g, 4.9g, 5.2g, good precision, good accuracy
4) Give an example of a homogenous and heterogeneous mixture? How are they different? Also, would CO_2 be a mixture?
Homogenous mixture would be anything like tea, alloys, salt water. Sand or rice pudding would be considered heterogeneous. Homogeneous are uniform while heterogeneous are not. CO2 is not a mixture, but a pure substance because the molecules are mixed together.
5) Match each experiment or discovery to the scientist famous for it. (Scientists can be used more than once!!) (Or write M, T, R next to each discovery/experiment)
T Cathode Ray R. Millikan
T Electron’s charge to mass ratio J.J Thomson
M Oil Drop Experiment E. Rutherford
M Actual charge of the electron
R Relative volume and mass of nucleus using Alpha Particles
T Plum Pudding Model
R Gold Foil Experiment
What does a mass spectrometer do?
Looks at all isotopes and makes an average atomic weight for the element
Draw methane, ethane, propane, butane, pentane. Write the empirical formula for each of them.
Methane: CH4 empirical: CH4
Ethane: C2H6 CH3
Propane: C3H8 C3H8
Butane: C4H10 C2H5
Pentane: C5H12 C5H12
Label the alkali metals, alkaline earth metals, transition metals, metalloids, halogens, chalcogens, and noble gases. What ion would each of these groups go for?
Group 1: Alkali Metals, Group 2: Alkaline Earth Metals, Group 3-12: Transition metals, Group 16: Chalcogens, Group 17: Halogens, Group 18: Noble Gases, Metalloids (See Book or ptable.com)
Alkali Metals : +1, Alkaline Earth : +2, Transition metals: depends, Chalcogens: -2, halogens: -1, noble gases: 0
Underline the sig figs in the following
254 100070 .0095 1.0055 0.002500 17100 19100.0
Round the final answers in each of the following to the appropriate sig figs:
84.0 + 37.56 = 121.6
78.223 * 32.2 = 2.52*10^3
23.34(78.4) + 18.99 = 1849
Read Law of Conservation of Mass, Law of Definite proportions, law of multiple proportions, and Dalton’s Laws on your own.
Write number of protons, neutrons, atomic mass, and electrons.
1531P 59Co (+2 charge) 41Zr (51 Neutrons)
15 P 27 P 40 P
16 N 32 N 51 N
31 amu 59 amu 91 amu
15 E 25 E 40 E
Write the name or chemical formula for each compound. Say whether its molecular or ionic.
NaOH Sodium Hydroxide I
Calcium Acetate Ca(CH3COO)_2 I
Cl2O3 Dichloride trioxide M
Ferric iodide FeI_3 I
K2SO4 Potassium Sulfate I
KCN Potassium Cyanide I
Lead (II) Carbonate PbCO_3 I
Ag2Cr2O7 Silver Dichromate I
CuOH2 Copper (II) Hydroxide I
Dinitrogen Tetroxide N2O4 M
Name these ions and the acid they would become.
BrO- hypobromite hypobromous acid
BrO2- bromite bromous acid
BrO3- bromate bromic acid
BrO4- Perbromate perbromic acid
What do Cl, F, H, and O have in common? Are there others like them?
Diatomic molecules, O2, N2, I2, Br2, Cl2, F2, H2
Which two transition metals always have a certain charge? What are their charges?
Ag+ and Zn2+
Automobile batteries contain sulfuric acid, which is commonly referred to as battery acid. Calculate the number of grams of sulfuric acid in 1.00 gallon of battery acid if the solution has a density of 1.28 g/ml and is 38.1% sulfuric acid by mass. (1 Gallon is 3.78541 L)
1850 g of H2SO4
Given the masses of three Br_2 isotopes (157.836, 159.834, and 161.832) determine the averace molecular mass of the Br_2 molecule. They respectively have 25.69%, 49.99%, and 24.31% rate of appearance.
159.790 amu
Page 105, exercises with drawings
Calculate the molecular weight of Acetic Acid.
60.04 amu
What is the percent of carbon by mass in acetic acid?
40%
Ibuprofen, a headache remedy, contains 75.69% C, 8.80% H, and 15.51% O by mass, and has a molar mass of 206 g/mol. What are the empirical and molecular formulas?
C13H18O2
Both empirical and molecular
Combustion analysis of toluene, a common organic solvent, gives 5.86 g of CO2, and 1.37g of H2O. If the compound contains only carbon and hydrogen, what is it’s empirical formula?
C7H8
78.34g of carbon is equivalent to how many particles of carbon?
3.9 * 10^24 molecules
3.9*1030 molecules is how many moles of CO2? How many particles of oxygen are in this many moles of CO2? How many grams of carbon are in this many molecules of CO2?
Don’t worry about this one, numbers turned out too big L
Hydrogen Sulfide is an impurity in natural gas that must be removed. One common removal method is called the Claus process, which relies on reacting hydrogen sulfide with oxygen both as gases. This produces S8(l) and water. Under optimal conditions the Claus process gives 98% yield of S8 from Hydrogen Sulfide. If you started with 30.0g of hydrogen sulfide and 50.0g of oxygen, how many grams of S8 would be produced, assuming 98% yield.
13.86g