Name___________________
Test 1 & 2 Reexamination
I. Fill in the Blank (10pts)
0.090010 mL has _____ significant figures
80020 ng has _____ significant figures
The correct answer to 6.37 m/s X 0.6607 s – 4.00042 should have _____
significant figures
A ___________ is a sub-atomic particle with a positive charge, but its mass is
almost the same as that of the __________.
There are ________ electrons in a
81Br
(bromine-81) atom.
The total number of neutrons in an atom of
207Pb
(lead-207) is ___________.
Different structural forms of an element are called _________________.
Varying the number of neutrons in an element creates _______________.
Neutral fluorine has __________ electrons.
II. Multiple Choice (16pts)
1. A burning lab coat is an _______________________________________.
A) exothermic physical change
B) endothermic chemical change
C) exothermic chemical change
D) endothermic physical change
2. Nail polish remover (acetone) evaporating is an ____________________.
A) exothermic physical change
B) endothermic chemical change
C) exothermic chemical change
D) endothermic physical change
3. The volume of an atom is primarily determined by
A) the number of neutrons
B) the volume dial
C) the innermost electron shell
D) the outermost electron shell
4. A dull substance that insulates against heat loss is probably a
A) metal
B) noble gas
C) non-metal
D) metalloid
5. A neutral selenium (Se) atom has _____ protons, _____ neutrons, and _____
electrons.
A) 45, 34, 34
B) 34, 45, 34
C) 45, 34, 45
D) 34, 79, 34
6. All chemical reactions involve:
A) liquids
B) a change in energy
C) a color change
D) exothermic processes
7. Metalloids are located _________________ on the periodic table.
A) to the left of the “stair steps”
B) to the right of the “stair steps”
C) on the “stair steps”
D) in group 18
8. An example of a very reactive element is:
A) Cesium (Cs)
B) Helium (He)
C) Neon (Ne)
D) Krypton (Kr)
9. A cylinder with a diameter of 24 mm and a height of 8.0 cm with a mass of
22.7 g has a density of ____________ g/cm3.
A) 0.0016
B) 0.63
C) 0.0063
D) 0.16
10. Which of the following elements would have properties most similar to
oxygen?
A) sulfur
B) fluorine
C) neon
D) nitrogen
11. This scientist postulated the existence of quantized energy levels for
electrons:
A) Bohr
B) Dalton
C) Thompson
D) Rutherford
12. All of the following can be used to separate a physical mixture except:
A) distillation
B) filtration
C) sublimation
D) decapitation
13. An example of an allotrope of sulfur is ______________________.
A) sulfonamides, a class of drugs containing sulfur, oxygen, carbon, hydrogen...
B) rhombic sulfur, yellow crystals of sulfur atoms arranged in an 8-pointed ring
C) sulfuric acid, a powerful acid with the chemical formula H2SO4
D) thiols, the family of sulfur compounds which give the skunk its smell
14. How many atoms of argon (Ar) would you find in a light bulb which contains
0.52 moles of argon?
A) 8.6 E–25 atoms
B) 21 atoms
C) 3.1 E+23 atoms
D) 77 atoms
15. How many moles of aluminum would you need to have a mass of 1.63 mg?
A) 0.060 moles
B) 6.0 E–5 moles
C) 44 moles
D) 0.044 moles
16. Sugar is classified as:
A) an element, a pure substance, and a solid
B) a homogenous mixture, matter, and a solid
C) a molecule, an allotrope, and a solid
D) a compound, a pure substance, and a solid
III. Electron Configurations – follow the directions
Write the full electron configuration for Indium (In). [2pts]
Write Noble gas electron configurations for silicon (Si) and osmium (Os). Would
you expect these elements to have similar properties? (You must give a reason.)
[3pts]
IV. Short Answer (3pts)
Water has a density of 1.00 g/mL
Liquid mercury has a density of 12.8 g/mL
Oil has a density of 0.83 g/mL
Draw and predict what will happen when the three are mixed together.
V. Calculations – Yes, significant figures matter!
Calculate the average atomic mass of magnesium, given the following
information about its two isotopes. [3pts]
Isotope
Mass (amu)
% abundance (%)
Magnesium-24
23.985
78.99
Magnesium-25
24.986
10.00
Magnesium-26
25.983
11.01
Calculate the number of atoms found in 24.7 cg of iodine. [3pts]