Exam 1 Review Supplemental Instruction Iowa State University Leader

1. 
   Which of the following is NOT a chemical reaction?
   

1. 
   Dissolution of penny in nitric acid
   
2. 
   Burning of a candle
   
3. 
   The melting of copper
   
4. 
   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

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.
(+2 charge) (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

Name these ions and the acid they would become.

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)

Calculate the molecular weight of Acetic Acid.

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?

Both empirical and molecular

78.34g of carbon is equivalent to how many particles of carbon?

3.9 * 10^23 molecules

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 (l) and water. Under optimal conditions the Claus process gives 98% yield of from Hydrogen Sulfide. If you started with 30.0g of hydrogen sulfide and 50.0g of oxygen, how many grams of would be produced, assuming 98% yield.

13.86g