Chemistry

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CHE 140 Name__Chesi Spriggs
First Hour Exam

Potentially useful information

1000 g = 1 kg 1000 mL = 1 L 1 in = 2.54 cm
1 mL = 1 cm3
D = m/v

Select the best choice for the following questions.

___e___ 1. A hypothesis is a(n)
a. formulation of principles based on facts.
b. modification of a theory.
c. organized body of knowledge.
d. tentative explanation of observations.
e. None of the above.

__b___ 2. The initial success of the Bohr theory was based on

a. its ability to predict the atomic spectra of multi-electron atoms. b. its ability to predict the atomic spectrum of hydrogen atoms. c. its prediction of the precise radius of electron orbits of hydrogen. d. its elegant inclusion of the Heisenberg uncertainty principle.

___c___ 3. . An object with a mass of 163.0 g displaces 28.6 mL of water. What is the density of the object.

a. 7.50 g/mL b. 9.25 g/mL
c. 5.70 g/mL d. 264.5 g/mL
e. None of the above.
SHOW WORK HERE:

D= 163.0/28.6
D=5.7

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__c___ 4. Of the following substances, the least dense is that of (HINT: estimate or calculate the density of the choices)? a. 1000 g of water at 4 oC
b. 100.0 cm3 of chloroform, which weighs 148.9 g
c. a 10.0 cm3 piece of wood weighing 7.72 g
d. an ethyl alcohol ‑ water mixture of density 0.83 g/mL.

__a___ 5. The scattering of alpha particles by thin metal foils established that
a. the mass and positive charge of an atom are concentrated in the nucleus. b. electrons are fundamental particles of all matter
c. all electrons have the same charge
d. atoms are electrically neutral.

__c__ 6. What is the electron configuration for Ar ?

a. 1s22s22p63s23p63d2

b. 1s22s22p63s23p64s2

c. 1s22s22p63s23p6

d. 1s22s22p62d83s2

___a___ 7. In science, the correct result for the multiplication 447.0 x 0.340 is

a. 152 c. 1.52x101
b. 152.3. d. 1.52x10-1
e. none of the above.

__d____ 8 A substance that has a definite volume and indefinite shape is a

a. vapor c. solid.
b. gas d. liquid.

___b__ 9. An example of chemical change is

a. the melting of ice cube b. the boiling of ethyl alcohol. c. the frying of an egg d. both a. and b.
e. all of the above.

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___a___ 10. The most abundant ordinary element in the universe is

a. Hydrogen b. Helium c. Nitrogen d. Oxygen
e. Carbon

___a___ 11. The longest length of the following choices is

a. 4.0 m b. 12 ft. c. 180 in d. 0.001 km.

___d___ 12. In an experiment to test how well methyl alcohol works as an antifreeze, a technician took 325 mL of this liquid. Its density is 0.810 g/mL. How many grams of methyl alcohol were taken?

a. 336 g b. 223 g c. 0.003 g d. 263 g
e. none of the above.
SHOW WORK HERE:

325*0.810= m/325 (325)
325 * 0.081= 263.25g

(13-17.) Choose the correct electronic configurations for the species listed below. Remember to use the core convention correctly for any species with an atomic number greater than ten.

___d_ 13. V a. [Ar]4s23d4 b. [Ar]4s13d6

c. [Ar]4s13d5 d. [Ar]4s23d3

e. None of the above.

__b___ 14. Zn a. [Ar]4s23d9 b. [Ar]4s23d3

b. [Ar]4s23d10 d. [Ar]4s13d10

e. None of the above.

__b___ 15. Ne. a. 1s22s23p6 b. 1s22s22p6

c. 1s22s13p6 d. 1s22s12p6

e. None of the above.

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___b__ 16. Br a. [Ar]4s23d104p6 b. [Ar]4s23d104p5

c. [Ar]4s23d104p4 d. [Ar]4s13d104p6

e. None of the above.

__d___17. Ba a. [Ar]5s24d105p6 b. [Xe]5s24d105p6

b. [Kr]5s24d105p4 d. [Xe]6s2

e. None of the above.

18. Write the names of the elements shown by their symbols:

a) Co ____cobalt__________ b) Au ___gold____________

c) I _iodine______________ d) Pu ___plutonium_______

e) Hg ___mercury_________ f) Sb ____antimony________

g) Ar ____argon___________ h) Li ____lithium__________...
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