CHE 110 Study Guide - Midterm Guide: Calcium Chloride, Weighted Arithmetic Mean, Roman Numerals
Chemistry Test Study Guide: Obj. 3, 4, & 5 (Ch. 2,4,5, & 8)
Chapter 1: Language of Chemistry (Stuff You Should Already Know)
• Macroscopic View- overall view (what we can see from the naked eye)
• Microscopic View- cannot see with the naked eye
• Matter: anything that has mass and occupies stuff
o All matter is composed of tiny, fundamental particles called
atoms.
o Solid: has a definite shape/volume with compact particles.
o Liquid: definite volume but not a definite shape with particles
that are free to move around but are still close together.
o Gas: indefinite volume/shape with particles that move
independently from one another.
• Substances: a particular kind of matter with a definite, fixed
composition.
o Pure Substance: either elements or compounds (ex: gold,
copper, oxygen, water, salt, and sugar)
o Homogenous/Heterogeneous Mixtures: Homogenous is uniform
in appearance and has the same properties throughout, while
heterogeneous consists of two or more physically distinct
phases.
o What is the difference between a mixture and a pure substance?
▪ A: Mixture always consist of 2+ substances that can be
separated by physically means, while Pure Substances are
elements/compounds that lose their identities and can
only be separated by chemical means.
• Law vs Theory: Theory is an explanation/prediction that may be
disproven, while a law is more general and cannot be proven wrong
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2
Chapter 2: Standards for Measurement
• Temperature: To convert C to K, add 273 (to convert K to C, sub. 273)
• Scientific Notation: move the decimal point so the number is between 1
ad , ad if ou oe the deial to the right, it’s a egatie epoet, if
ou oe it to the left, it’s a positie epoet.
o (Ex: 5283 →5.283 x 10^3 Ex: 4,500,000,000 → 4.5 x 10^9)
• Whenever measuring something, make sure you go one number further
than the actual measurement (Ex: if the thermometer reads 49.5 degrees
ake sure ou either sa it’s . or . degrees. Nuers gathered
from a measurement are never exact values!!!
• Significant Figures (Sig Figs) Rules:
o Nonzero digits are always significant (Ex: 432 has 3 sig figs)
o Exact numbers (Ex: if a scale reads 4.56789, there are 6 sig figs)
o )eros are sigifiat he the’re etee o-zero numbers (Ex:
205 & 2.05 both have 3 sig figs), and at the end of a number that
includes a decimal point (Ex: .500 has 3 sig figs, 25.160 has 5 sig figs,
20. Has 2 sig figs, and 3.00 has 3 sig figs)
o Zeros are NOT sigifiat if the’re efore the first ozero digit
E: . has sig figs, . has sig figs or if the’re at the ed of
a number without a decimal point (Ex: 1000 has 1 sig fig, 590 has 2
sig figs)
o When you multiply/divide numbers using sig figs, the answer must
have the same number of sig figs as the least number of sig figs (Ex:
5.4 x 2.34 = 12.6)
o When you add/subtract numbers using sig figs, the answer is
rounded to the same number of decimal places as the value with the
least amount of decimal places (Ex: 125.17 + 129 + 52.2 = 306)
• Metric System: Terms to know are kilo- (1000 x unit), centi- (.01 x unit),
milli- (.001 x unit), and nano- (10^-9 x unit)
o Length is measure in meters, Mass is measured in kilograms,
Temperature is measured in Kelvin, Volume is measured in mL
• Percent: Mass percent = mass part / mass whole x 100%
• Density: mass (g) / volume (mL)
o Changes with temperature because the particles spread out and the
mass stays the same (volume expands with heat)
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