Chemistry Review: 1st Quarter
Name: _____KEY__________________
PART I: You should know the basics (terms & basic facts) about…
Hypothesis
theory
law
scientific method
mass
weight
volume
physical change
chemical change
mixture
element
compound
molecule
heterogeneous
homogeneous
states of matter
Dalton’s Atomic Theory
precision
accuracy
proton
neutron
Electron
isotope
atomic number
mass number
average atomic mass
frequency
wavelength
photons
Aufbau principle
Pauli exclusion principle
Ground state
Excited state
Energy level
Orbitals
Electron spin
ion
atom
molecule
compound
alpha particles
beta particles
gamma ray
Half-life
fission
fusion
octet rule
PART II - You should be able to complete the following problems (MUST SHOW WORK for MATH calculations)
PHYSICAL OR CHEMICAL CHANGE
boiling water: ___PHYSICAL____
burning wood: ____CHEMICAL___________
melting aluminum: __PHYSICAL____
EXTENSIVE OR INTENSIVE PROPERTIES
Boiling point: __INTENSIVE_____
Volume: __EXTENSIVE___________
CONVERSIONS:
Convert 54 millimeters to Megameters
separating sand from water: _ PHYSICAL____
Energy (heat content): __EXTENSIVE________
Density: ____INTENSIVE___________________
5.4 X 10-8 Megameters
Convert 9.2 X 10-5 Kg to g.
0.092 grams
Convert 1234 meters to miles
0.77 miles
HINT Basic Conversion Units: 2.54cm = 1 inch, 0.946 L = 1 quart, 454 g = 1 lb, 1 mile = 5280 ft
SIGNIFICANT DIGITS
How many significant figures number are expressed in the following examples?
0.0003040 mm __4____ 29000. __5____ 9.10 x 1045 L __3______
1.05 g __3____
Round 8.9456 to 3 significant digits: ___8.95_____
Round 513431 to 2 significant digits: _5.1 x 10 5_
or
510 000
Determine the answer for each of the following. Be sure to use the correct number of significant figures.
17.34 + 4.900+ 23.1 = __45.3__
9.80 – 4.762 = ___5.04__________
3.9 x 6.05 x 420 = __9900___
14.1 / 5 = ___3__________________
COUNTING PROTONS, NEUTRONS, AND ELECTRONS
HYPHEN
NOTATION
NUCLEAR SYMBOL
201
80
PROTONS
NEUTRONS
ELECTRONS
CHARGE
4
5
0
47
61
0
16
17
-2
13
15
+3
Hg
48
60
28
36
+1
Ni
80
34
Se -2
16
8
O -2
BALANCE NUCLEAR REACTION EQUATIONS
ANSWERS: Calcium-40, Magnesium-26 & Thorium-234
aluminum-26 undergoes positron emission: ___________________________________________
potassium-40 undergoes beta decay: _________________________________________________
uranium-238 undergoes alpha decay: _________________________________________________
ELECTRON CONFIGURATIONS
Write the electron configuration for Carbon: _____________________________________
Write the noble gas notation for Platinum: ______________________________________
DENSITY
What is the volume of a solid with a density of 7.8 g/mL and a mass of 11.8 g ?
1.5 mL
HALF-LIFE
Tritium (H-3) is a radioactive isotope of hydrogen with a half-life of 12.3 years. How long would it take for a 40.0 g
sample to decay down to 1.25 g?
61.5 years
Fe-61 has a half-life of 6.00 min. Of a 100.0 mg sample, how much will remain after 18.0 min?
12.5 mg
MOLES, MOLECULES & GRAM CONVERSIONS
How many grams are in 6.8 moles of H2O?
122.45 g H2O
4.33 x 1022 atoms NaCl
How many atoms are there in 4.2 grams of NaCl?
How many grams are there in 5.62 x 1023 atoms of CH 4?
14.98 grams CH4
VALENCE ELECTRONS & OXIDATION NUMBER
Elements
Number of Valence Electrons
ANSWERS: -3 , -1, 2, +2, 3, +3, 5, 7
Oxidation Number (charge)
Strontium
Phosphorus
Boron
Iodine
QUANTUM NUMBERS
Quantum numbers for the following elements are
Y: _______, _______, _______, _______
Identify the following elements:
ANSWERS: -2, - ½ , + ½ , 0, 1, 2, 4, 4, Pb, Rh
Br: ______, ______, ______, ______
6, 1, 0, + ½ : _________________
4, 2, -1, - ½ : _______________
WAVE PARTICLE PROBLEM
Ultraviolet light causes a chemical reaction in your skin and darkens the pigments in your skin. If the wavelength of
these photons is 200 nanometers,
2 x 10-7 meters
Find the wavelength in meters (convert nanometers to meters):
1.5 x 10 15/s
Find the frequency
9.94 x 10-19 J
Find the energy of these photons
CONCEPT QUESTIONS: Identify the letter of the choice that best completes the statement or answers the question.
ANSWERS: A, B, B, B, B, B, C, C
____ 1. Most of the mass of an atom is found
a. In the electron cloud.
c. in the number of protons.
b. in the nucleus.
d. in the outer region of an atom.
____
2. A spherical electron cloud surrounding an atomic nucleus would best represent
a. an s orbital.
c. a combination of px and py orbitals.
b. a px orbital.
d. a combination of an s and a px orbital.
____
3. For an electron in an atom to change from the ground state to an excited state,
a. energy must be released.
b. energy must be absorbed.
c. radiation must be emitted.
d. the electron must make a transition from a higher to a lower energy level.
____
4. Which two compounds are examples of the law of multiple proportions?
a. FeCl3 and Fe2(SO4)3
c. CO and CO2
b. O2 and O3
d. FeCl2 and Fe(NO3)2
____
5. The energy of a photon, or quantum, is related to its
a. mass.
b. speed.
c. frequency.
____
6. Written in scientific notation, the measurement 0.000 065 cm is
a. 65 x 10–4 cm.
c. 6.5 x 10–6 cm.
–5
b. 6.5 x 10 cm.
d. 6.5 x 10–4 cm.
____
7. Atoms of the same element that have different masses are called
a. moles.
b. isotopes.
c. nuclides.
____
d. size.
d. neutrons.
8. A nuclear particle that has about the same mass as a proton, but with no electrical charge, is called a(n)
a. nuclide.
b. neutron.
c. electron.
d. isotope.
Answers: 9.945 x 10-19
5.4 x 10-8 2 x 10-7 0.092 0.77
45.3
61.5
122.45
9900
1.5
3
1.5 x 1015
5.04
12.5
22
4.3 x 10
14.98