Download Chemistry Midterm Exam 2015 (Study Guide) Unit 1: Measurement

Chemistry Midterm Exam 2015 (Study Guide)
Unit 1: Measurement in chemistry
Define:
1. Theory
2. Law
3. Significant figure
4. Accuracy
5. Precision
6. Scientific theory can never be __proven____.
7. The first figure in a properly written chemical symbol always is __capitalized__.
8. What does the following represent: ( element, compound, ion, isotope )
a. Cl - element
c. H2O- compound
b. Al-3 ion
d. O-16 isotope
9. The closeness of a measurement to its true value is a measure of its __accuracy__.
10. Which group of measurements is the most precise? (Each group of measurements is for a different object.)
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
a. 2 g, 3 g, 4 g
c. 2 g, 2.5 g, 3 g
b. 2.0 g, 3.0 g, 4.0 g
d. 1 g, 3 g, 5 g
In the measurement 0.202 L, which digit is the estimated digit? The last 2
How many significant figures are in the measurement 0.0027 kg? 2
How many significant figures are in the measurement 480,500 mg? 4
Express the sum of 7.68 m and 5.0 m using the correct number of significant digits. 12.7
Express the product of 2.2 mm and 5.00 mm using the correct number of significant digits. 11
What is the SI unit of mass? kilogrm
What is the formula to covert Celsius to kelvin? (C= K-273) Kelvin to Celsius? (k=C+273)
Convert this temperature –30 C to kelvins. 303K
Convert 239 K. to Celsius? -34
What is the formula for density? Mass/vol
21. What is the density of an object having a mass of 8.0 g and a volume of 25 cm ? 8/25=0.32g/cm3
Unit 2: Atomic History & Structure
Define:
22.
23.
24.
25.
26.
27.
Atom
Isotope
Ion
Atomic number
Mass number- protons + neutrons in the nucleus of a particular atom
Average Atomic mass- the average of all the isotopes and their abundance.
28. Give the 4 major points of Dalton’s atomic Theory.
a.
b.
c.
d.
All thing are made of atoms
Atoms of the same kinds are alike
Atoms combine to make compounds
In reactions, atoms rearrange to make new compounds
29.
30.
31.
32.
33.
34.
35.
What did Rutherford discover and what his experiment? Gold foil experiment and discovered the proton.
What did Thomson discover and atom called? Plum pudding model and discovered the electron
All atoms are neutral with the number or ____protons______ equaling the number of __electrons___.
The particles that are found in the nucleus of an atom are __protons__ & ___neutrons___.
What does the number 84 in the name krypton-84 represent? Mass number
All atoms of the same element have the same number of __protons__.
Isotopes of the same element have different number of _neutrons___ which causes them to have different
__mass____ too.
36. The mass number of an element is equal to the total number of _protons___ & ___neutrons___ in the nucleus of
an atom
37. Using the periodic table, determine the number of neutrons in O. 16-8=8
38. How many protons, electrons, and neutrons does an atom with atomic number 55 and mass number 125 contain?
P=55, E=55, N=125-55=70
39. Which of the following sets of symbols represents isotopes of the same element?
a.
c.
J
J
J
M M M
b.
L
L
L
d.
Q
Q
Q
40. What unit is used to measure weighted average atomic mass? amu
41. The atomic mass of an element depends upon the ____.
a. mass of each electron in that element
b. mass of each isotope of that element
c. relative abundance of protons in that element
d. mass and relative abundance of each isotope of that element
42. Consider an element Z that has two naturally occurring isotopes with the following percent abundances: the isotope
with a mass number of 19.0 is 55.0% abundant; the isotope with a mass number of 21.0 is 45.0% abundant. What is
the average atomic mass for element Z?
19 x .55 = 10.5amu
21 x .45 = 9.45 amu
-------------------------------------------Total = 19.9 amu
Unit 2: Electron Configuration
43. What is the maximum number of electrons in the second principal energy level? 8
44. What types of atomic orbitals are in the third principal energy level? s, p, d
45. What is the number of electrons in the outermost energy level of an oxygen atom? 6
46. What is the electron configuration of potassium? 1s2, 2s2,2p6,3s2,3p6,4s1
47. Which of the following electron configurations of outer sublevels is the most stable?
a. 5s 4d
c. 4d 5s
b. 5s 4d
d. 4d 5s
48. List the elements is in the same period as Nitrogen? Li, Be, B, C, Ne, F
49. What element has the electron configuration 1s 2s 2p 3s 3p ? Silicon (Si)
50. Each period in the periodic table corresponds to the principal __energy____ level
Unit 3: Periodic table and Periodic Trends
Define:
51. Representative element
52. Transition element
53. Metals
54. Non-metals
55. Electronegativity
56.
57.
58.
59.
60.
61.
62.
Ionization energy
The modern periodic table is arranged in order of increasing atomic _number___.
What category includes the majority of the elements? (metals / non-metals/ metalloids)
Where are the metals located on the periodic table? Left of zigzag line
Where are the non-metals located on the periodic table? Right of the zig zag line
To what category of elements does an element belong if it is a poor conductor of electricity? Non-metals
In which of the following sets is the symbol of the element, the number of protons, and the number of electrons
given correctly?
a. In, 49 protons, 49 electrons
c. Cs, 55 protons, 132.9 electrons
b. Zn, 30 protons, 60 electrons
d. F, 19 protons, 19 electrons
63.
64.
65.
66.
67.
68.
Draw the arrows for atomic radius, ionization energy, and electronegativity.
What is important about the electron configurations of the noble gases? They all have full energy levels.
What subatomic particle plays the greatest part in determining the properties of an element? electron
Where are the transition metals located? Columns 3-12 (B=group)
How does atomic radius change from top to bottom in a group in the periodic table? It increases
What causes the shielding effect to remain constant across a period? Electrons are being added to the same energy
level.
What is the charge of a cation?(+) anion?(-)
How does a cation and anion form? cation forms by an atom losing electrons. Anion forms by an atom gaining
electrons
The metals in Groups 1A, 2A, and 3A __lose__ electrons to form ions.
What are the charges (oxidation numbers) for the following groups: 1A_+1__, 2A__+2__, 3A__+3__, 5A__-3__
6A__-2__ 7A__-1__ 8A__0__
69.
70.
71.
72.
73. What are the valence electrons for the following groups: 1A_1__, 2A__2__, 3A__3__, 5A__5__ 6A__6__ 7A__7__
8A__8__
74. As you move from left to right across the second period of the periodic table ionization and electronegativity
__increases___.
Unit 4: Covalent & Ionic Bonding
75. Write a t-chart comparing and contrasting ionic / covalent bonds.
a. Ionic= made of metals & non-metals/exchanges or transfers electrons/ cation & anions/ strong bond/ high
melting pts & boiling pts/ crystal structures/ can conduct electricity when dissolved in water/ called formula
units
b. Covalent- made of all non-metals/ shares electrons/ no charges/ weak bond/ low m.p and b.p / mostly
gasses or liquids/ cannot conduct electricity / called molecules
76. Ionic compounds are composed of opposite charged ions called ____cations____ and ___anions_____.
77. Molecular compounds are usually composed of 2 or more _____non-metals_________________.
78. When do you use a roman numeral when naming compounds? Which type of compound uses roman numerals?
When the compound has a transition metal that can have more than one charge
79. Write the correct name for the compound CoCl ? Cobalt (II) Chloride
80. What compounds do you use prefixes in the naming? What to the prefixes represents? Covalent compounds (aka.
Molecular) the prefixes represent the subscripts in the formulas
81. Most compounds that end in –ate or –ite end with a _____polyatomic____________ anion.
82. List your 7 diatomic molecules. H2, N2, O2, F2, I2, Br2
83.
84. Write the correct formula for sulfur hexafluoride. SF6
85. Write the correct formula for barium chlorate? Ba(ClO3)2
86. Write the correct name for N O .DiNitrogen pentoxide