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Glossary of CHE 111: Exam I

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What is matter?
Anything that has mass and occupies space
What is a property?
Any characteristic that makes that sample of matter unique
What is chemistry?
The study of matter, its properties and behaviors, and how it changes and interacts with other matter
What are the three forms of matter and their properties?
Gas: No fixed volume and no fixed shape
Liquid: Definite volume and indefinite shape
Solid: Definite volume and definite shape
How can the forms, or states, of matter be changed?
Applying heat or pressure
What is an element?
A substance made of one type of atom that cannot be broken down into simpler substances by chemical means
What is a pure substance?
Matter that has a fixed composition and distinct properties, ie, gold or salt
How many elements are there?
116 known elements, 91 of which are naturally occurring
What is a compound?
A substance composed of two or more elements chemically combined in a specific ratio of atoms as noted by its chemical formula
What is a mixture?
A combination of two or more substances physically combined in which each substance retains its own chemical identity
When combining two or more elements, what are the two possible results?
If they react to form a new substance, you have a compound
If they do not react but instead retain their individuality, you have a mixture
How can compounds be separated?
Through heat or electrolysis
What are the two types of mixtures?
Homogeneous and heterogeneous
What is a solution?
A homogeneous mixture of substances with a uniform composition of a solvent and solute
What is a solvent?
The dissolving medium of a solution that is usually in greater quantity
What is a solute?
A substance dissolved in a solvent to form a solution that is usually in lesser quantity
What is a homogeneous mixture?
A mixture that is consistant throughout, ie, solutions with dissolved substances
What is a heterogeneous mixture?
A mixture that has inconsistant concentrations of elements, ie, rocks or wood
How do you separate a liquid-solid mixture?
Through filtration and decanting the liquid
How do you separate a homogeneous liquid solution?
Through distillation
What is chromatography used for?
To separate mixtures by size and reactivity
What is TLC?
Thin line chromatography
What are four kinds of properties?
Physical and chemical, as well as intensive and extensive
What are physical properties?
Properties that can be measured without changing the identity and composition of the substance, such as boiling/melting points, color, density, and odor
What are chemical properties?
Properties that describe the reactivity with other substances
What are intensive properties?
Properties that do not depend on the quantity present, ie color, temperature, melting/boiling points, and density
What are extensive properties?
Properties that depend on the quantity present, ie, mass, volume, and solubility
What are two types of changes in substances?
Physical and chemical
What are physical changes?
The change in state or physical appearance but not in composition
What are chemical changes?
Aka chemical reactions
The change of a substance into a chemically different substance
H
hydrogen
He
helium
Li
lithium
Be
beryllium
B
boron
C
carbon
N
nitrogen
O
oxygen
F
fluorine
Ne
neon
Na
sodium
Mg
magnesium
Al
aluminium
Si
silicon
P
phosphorous
S
sulfur
Cl
chlorine
Ar
argon
K
potassium
Ca
calcium
Sc
scandium
Ti
titanium
V
vanadium
Cr
chromium
Mn
manganese
Fe
iron
Co
cobalt
Ni
nickel
Cu
copper
Zn
zinc
Br
bromine
Kr
krypton
Rb
rubidium
Zr
zirconium
Ag
silver
I
iodine
Xe
xenon
Cs
caesium
Ba
barium
Pt
platinum
Au
gold
Hg
mercury
Pb
lead
U
uranium
Pu
plutonium
Why is it important to study chemistry?
It helps us understand our world and how it works. It's also a central science upon which all other sciences and technologies are based.
What is a molecule?
A chemical combination of two or more atoms
What are the states of matter?
The three forms of matter (liquid, gas, solid)
What is the law of constant composition?
aka the law of definite proportions
A law that states that the elemental composition of a pure compound is always the same, regardless of its source
What else are homogeneous mixtures known as?
Solutions
What kind of changes are all changes of state?
Physical changes
What is the scientific method?
The general process of advancing scientific knowledge by making experimental observations and by formulating hypotheses, theories, and laws
What is a hypothesis?
A tentative explanation of a series of observations or of a natural law
What is a scientific law?
A concise verbal statement or a mathematical equation that summarizes a wide range of observations and experiences
What is a theory?
A tested model or explanation that satisifactorily accounts for a certain set of phenomena
What is the metric system?
A system of measurement used in both science and in most countries.
What are SI?
Systeme International d'Unites, the preferred units in scientific measurements
What is the base SI unit for mass?
Kilogram (kg)
What is the base SI unit for length?
Meter (m)
What is mass?
A measure of the amount of material in an object. It measures the resistance of an object to being moved.
What is the base SI unit for time?
Seconds (s or sec)
What is the base SI unit for temperature?
Kelvin (K)
What is the base SI unit for the amount of substance?
Mole (mol)
What is the base SI unit for an electric current?
Ampere (A)
What is the base SI unit for luminous intensity?
Candela (cd)
What is the abbreviation and meaning of the prefix giga?
G
10 to the power of 9
What is the abbreviation and meaning of the prefix mega?
M
10 to the power of 6
What is the abbreviation and meaning of the prefix kilo?
k
10 to the power of 3
What is the abbreviation and meaning of the prefix deci?
d
10 to the power of -1
What is the abbreviation and meaning of the prefix centi?
c
10 to the power of -2
What is the abbreviation and meaning of the prefix milli?
m
10 to the power of -3
What is the abbreviation and meaning of the prefix of micro?
μ
10 to the power of -6
What is the abbreviation and meaning of the prefix nano?
n
10 to the power of -9
What is the abbreviation and meaning of the prefix pico?
p
10 to the power of -12
What is the abbreviation and meaning of the prefix femto?
f
10 to the power of -15
What is temperature?
A measure of the hotness and coldness of an object
What is the Celsius scale?
Everyday temperature scale of most countries
Based on the assignment of 0°C to the freezing point of water and 100°C to its boiling point at sea level
What is the Kelvin scale?
SI temperature scale
Based on properties of gases
What is absolute zero?
Zero on the Kelvin scale
The lowest attainable temperature
-273.15°C
How are the Kelvin and Celsius scales related?
K = °C + 273.15
On the Fahrenheit scale, what are the points at which water freezes and boils?
Freezes: 32°F
Boils: 212°F
How are the Fahrenheit and Celsius scales related?
°C = 5/9 (°F -32)
or
°F = 9/5 (°C) + 32
What is the formula for speed?
The ratio of distance traveled to the elapsed time
Length/time in SI units would be m/s (read as meters divided by seconds)
How is the volume of a cube given?
Length raised to the third power, which can be in cubic meters (m cubed) or in cubic centimeters (cm cubed or also written as cc)
What does the liter (L) equal?
A cubic decimeter (dm cubed)
(L is not an SI unit)
How many milliliters (mL) are in a liter?
1000 mL
In expressing volume, which terms are interchangeably used, and why?
Milliliter and cubic centimeter because 1 mL = 1 cubic centimeter
What are the most common devices used in chemistry to measure volume, and which have the most precision?
Graduated cylinder, syringe, buret, pipet, and volumetric flask
Syringes, burets, and pipets are the most precise
What is density?
A property of matter used to characterize substances defined as the ratio of an object's mass to its volume.
Density = mass/volume
What are the volume relationships?
1 L = 1 dm cubed
1 mL = 1 cm cubed
1 m cubed = 1000 dm cubed
Densities are dependent on what?
Temperature
How are the densities of solids and liquids commonly expressed?
grams per cubic centimeter (g/cc or g/cm cubed)
or
grams per milliliter (g/mL)
What is the density of water?
100 g/mL
How was the gram originally defined?
The mass of 1 mL of water at a specific temperature
What are exact numbers?
Numbers whose values are known exactly
I.e. 2.54 cm = 1 inch
What are inexact numbers?
Numbers whose values have some uncertainty
Numbers obtained by measurement are always _____.
Inexact because of equipment errors or human errors (wrong calibration or rounding is off)

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