CHEM125-C                                                                                                  Fall, 2005

Hourly Exam # 1                                                                                             Dunnivant

 

Name (PRINTED) ____________________________________

 

There are 100 points.  The exam will be graded on a percentage basis.

 

The honor statement must be signed in order for your exam to be graded.

Closed book, closed Internet, closed notes, closed neighbor!

I have neither given nor received aid on this exam.  

                                                            Signature ________________________

 

Avogadros number = 6.022 x 1023 items/mol           

amu = 1.6605 x 10-24 g/amu

electron charge = 1.602 x 10-19 C

mass of neutron = 1.6749 x 10-24 g

mass of electron = 9.1094 x 10-28 g

mass of proton = 1.6726 x 10-24 g

 

NOTES:

-Show all work for partial credit.  

-Significant figures and units will be graded throughout the exam.

 

1.     (2 pts each):

 

Name or give the chemical formula for

 

Hydrogen sulfide        ___________________         

 

Sodium perchlorate     ___________________

 

Calcium nitrite ___________________

 

Potassium dichromate ___________________

 

Iron (III) chloride        ___________________

 

Calcium bicarbonate    ___________________

 

2.     (2.5 pts each) Write the name and chemical formula for

 

An metal-alkaline earth salt     ___________________

 

An anion of a halide    ___________________

 

A transition metal ion  ___________________

 

A metalloid      ___________________

 

3.      (5 pts) Yahoo weather says that the temperature for today is supposed to reach 69.0oF.  What is this temperature in degrees C and degrees K?

 

 

4.     (5 pts) A gallon of water weighs 7.44 pounds.  What is the weight of 4.68 gallons of water in milligrams?  Express your answer in scientific notation.

 

 

5.     (5 pts)  Convert 7.44 pounds of water to mL.  Express your answer in scientific notation.

 

 

6.     (10 pts) Complete and balance the following reactions:

 

Na(s)    +     H2O

 

 

C3H8    +     O2

 

 

Na(s)    +      Cl2 

 

 

CaO    +     H2O 

 

 

Ni(II)(s)     +      HCl 

 

 

 

7.     (15 pts) Determine the empirical and molecular formulas of the following:  ibuprofen, a headache remedy that contains 75.69% C, 8.80 % H, and 15.51% O by mass, molar mass about 206 g/mol.

 

Empirical formula:  ____________________

Molecular formula:  ___________________

 

 

8.  (15 pts) 150. grams of benzene is placed in a sealed flask containing 150. grams of O2 and combusted. Answer the following questions and draw and fill in a complete flow chart for all reactants and products.

 

a) The limiting reactant is _____________________

 

b)create a complete flow chart for the reaction in the space given below

 

c)determine how much (in grams) of the reactant that is present in abundance will be left in the flask (how much of the non-limiting reagent will be left over?).

 

 

 

limit your answer to the following question on this page. BE NEAT!

9.      (15 pts) Explain the experiment(s) that dispelled the plum pudding model of atomic structure. 

a)Who did it? 

 

b)Draw it. 

 

c)Explain the logic behind the argument against the plum pudding model.

 

 

 

10.  (10 pts)  Explain how we get from very tiny weights of neutrons, protons, and electrons to a mole.  Use an atom and a mole of lead-82 isotope (82Pb) in your explanation.  After you have finished the rest of the exam, go to the computer room and TYPE your answer, use a font size NO SMALLER THEN 12, and single space the text.  Limit your answer to 1 page.