CHEM 111G – Chemistry

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What is Chemistry?
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Chemistry is the study of matter and its interactions
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What is Matter
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A Substance that occupies space.
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The Scientific Method
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Observation > Formulation of a Hypothesis > Experiments to test the Hypothesis. A Hypothesis can only be proven FALSE
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Hypothesis
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Educated guess
Tentative explanation for a set of observations.
We must try and prove it to be WRONG, and not to be RIGHT.
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Theory
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Overarching model of reality
Concise verbal or mathematical statement of a relationship between phenomena that is always the same under the same conditions.
Lots experiments to help us understand what we are experimenting.
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Law
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Generally accepted description of reality.
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Qualitative Data
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General observations about the system
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Quantitative Data
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Numerical measurement made describing the system
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Substance
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Pure > Element, compound, and molecule
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Mixture: Homogeneous
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More than one substance but each is distributed throughout the other in the matter in which I can’t go in and just separating them, isolating them.
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Mixture: Heterogeneous
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Even though small, and same color, but can make the separation.
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Elements
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Substance that cannot be separated into simpler substances by chemical means (112-118 total elements)
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Measurement: Macroscopic
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Measured directly
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Measurement: Microscopic
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Measured Indirectly
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SI
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International System of Unit. Internationally assigned units.
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Physical Property
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Can be measured and observed without changing the composition or identity of a substance
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Chemical Property
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Observation requires a chemical change in the substance
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Chemical Property: Extensive Property
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Depends on how much matter is considered. Mass, length, and volume.
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Chemical Property: Intensive Property
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Independent of the amount of matter considered.
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Mass
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Measurement of the amount of a substance
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Weight
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Measurement of the force exerted on an object by gravity
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Length Cubed: Volume
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Length * Width * Height = Volume
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Tera (?)
Giga (?)
Mega (?)
Kilo (?)
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Tera (T)- 10^12 = 1,000,000,000,000
Giga (G)- 10^9 = 1,000,000,000
Mega (M)- 10^6 = 1,000,000
Kilo (k)- 10^3 = 1.000
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Deci (?)
Centi (?)
Milli (?)
Micro (?)
Nano (?)
Pico (?)
Femto (?)
Atto (?)
Zepo (?)
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Deci (d)- 10^-1 = 1/10
Centi (c)- 10^-2 = 1/100
Milli (m)- 10^-3 = 1/1,000
Micro (µ)- 10^-6 = 1/1,000,000
Nano (n)- 10^-9 = 1/1,000,000,000
Pico (p)- 10^-12 = 1/1,000,000,000,000
Femto (f)- 10^-15
Atto (a)- 10^-18
Zepo (z)- 10^-21
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Density
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Mass of an object or substance per unit volume occupied by that object or substance. Density = Mass/Volume
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Temperatures
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Fahrenheit, oF
Calsius (or Centigrade), oC
Kelvin, K
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Temperatures: Equations
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C= (F-32F)(5C/9F)
F= (9F/5C)(C)+32F
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Significant Figures
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Designation of the meaningful digits in a measured or calculated quantity. (5.6 vs 5.65)
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Meniscus
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The bottom of the lip of the fluid or matter. The floating point number.
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Significant Figures: Guidelines
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1. Any nonzero digits are significant
2. Zeros between nonzero digits are significant
3. Zeros to the left of first nonzero digit are not significant
4. If number is >1, all zeros written to the right of the decimal point a significant.
5. For numbers not containing a decimal point, trailing zeros (zeros after the last nonzero digit) are not significant.
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Accuracy
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How close a measurement is to the “true” value.
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Precision
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How reproducible are the measurements.
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The Dimensional Analysis Method of Solving Problems
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1. Identify the information giving regarding the problem
2. Identify the question being asked
3. Determine the units of each quantity pro6. vided
4. Determine the units of the quantity sought
5. Determine and use conversion factors to convert units of given information to units of requested quantity
6. Estimate the magnitude of the answer
7. Do the calculations
8. Determine if the calculated result is in agreement with estimated results (Does the answer “make sense”?)
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Solid
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A for of matter that has a definite shape and volume.
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Liquid
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A for of matter that occupies a definite volume but flows to assume the shape of its containers.
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Gas
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A for of matter that has neither definite volume nor shape, and that expands to fill its containers also called vapor
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Atom
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The smallest particle of an element that retains the chemical characteristics of the element
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Molecule
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A collection of atoms chemically bonded together
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Chemical Bond
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A force that holds two atoms in a molecule or a compound together.
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Sublimation
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Transformation of a solid directly into a vapor (gas)
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Deposition
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Transformation of a vapor (gas) directly into a solid
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Energy
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The ability to work
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Work
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The energy required to move an object through a given distance
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Heat
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A flow of energy from one object or place to another due to differences in the temperatures of the objects or places.
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Chemical Reaction
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The conversion of one or more substance into one or more different substances.
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Potential Energy (??)
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FE: The energy stored in an object because of its position
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Kinetic Energy (??)
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KE: the energy of an object in motion due to its mass (m) and its speed (u): KE = (1/2)*m*u^2
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Law of Conservation of Energy
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the principle that energy cannot be created or destroyed, but can be changed from one form to another
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Pure Substance
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Matter that cannot be separated into simpler matter by a physical process.
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Physical Process
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A transformation of a sample of matter, such as a change in its physical state, that does not alter the chemical identity of any substance.
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Element
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A pure substance that cannot be separated into simpler substances by any chemical substance.
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Compounds (book)
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A pure substance that is composed of two or more elements linked together in fixed proportions and that can be broken down into those elements by some chemical processes.
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Chemical Formula
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A notation for representing the elemental composition of a pure substance using the symbols of the elements; subscripts indicate the relative number of atoms of each element in the substance.
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Law of Constant Composition
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The principle that all samples of a particular compounds always contains the same elements combined in the same proportions.
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Mixture
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A combination of pure substances in variable proportions in which the individual substances retain their chemical identities and can be separated from one another by a physical process.
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Solution
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Another name for a homogeneous mixture. Solutions are often liquids, but they may also be solids or gases.
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Immiscible Liquids
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Combination of liquids that are incapable of mixing with, or dissolving in, each other.
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Distillation
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A process using evaporation and condensation to separate a mixture of substances with different volatilities.
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Volatility
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A measure of how readily a substance vaporizes.
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Filtration
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A process for seperating solid particles from a liquid or gaseous sample by passing the sample through a porous material that retains the solid particles.
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Chromatography
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A process involving stationary and mobile phases for separating a mixture of substances based on their different affinities for the two types of phases.
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Intensive Property
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A property that is independent of the amount of substance present.
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Extensive Property
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A property that varies with the amount of substance present
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Physical Property
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A property of a substance the can be observed without changing the substance into another substance.
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Density
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The ratio of the mass (m) of an object to its volume (V). d = m/V
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Chemical Property
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A property of a substance that can be observed only by reacting the substance chemically to form another substance.
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Scientific Law
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A concise and generally applicable statement of a fundamental scientific principle.
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Law of Definite Proportions
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The principle that compounds always contain the same proportions of their component elements; equivalent to the law of constant composition
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Scientific Theory
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A general explanation of widely observed phenomena that has been extensively tested.
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Hypothesis
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A tentative and testable explanation for an observation.
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Law of Multiple Proportions
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The principle that, when two masses of one element react with a given masses of another to form two different compounds, the two masses of the first element have a ratio of two small whole numbers.
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Molecular Formula
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A chemical formula that shows how many atoms of each element are in one molecule.
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Structural Formula
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A representation of a molecule that uses short lines between the symbols of elements to show chemical bonds between atoms.
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Meter (?)
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(M) The standard Greek unit of metron, which means measure; equivalent to 39.37 inches.
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Joule (?)
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J: The SI unit of energy, equivalent to 1kg*(m/s)^2
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Kilogram (kg)
Meter (m)
Kelvin (K)
Second (s)
Ampere (A)
Mole (mol)
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Mass
Length
Temperature
Time
Electric Current
Quntity of a Substance
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Mass
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1kg = 2.205 pounds (lb); 1lb = 0.4536kg =453.6g
1g=0.03527 ounce (oz); 1oz = 28.35g
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Length (distance)
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1m = 1.094 yards (yd); 1yd = 0.9144m (exactly)
1m = 39.37 inches (in); 1 foot (ft) = 0.3048m (exactly)
1in = 2.54cm (exactly)
1km = 0.6214 miles(mi); 1mi = 1.609km
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Volume
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1m^3 = 35.31ft^3; 1ft^3 = 0.02832m^3
1m^3 = 1000 liters(L)(exactly)
1L = 0.2642gallon(gal); 1gal = 3.785L
1L = 1.057 quarts(qt); 1qt = 0.9464L
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Precision
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The extent to which repeated measurements of the same variable agree
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Accuracy
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Agreement between an experiment value and the true value.
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Significant Figure
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All the certain digits in a measured value plus one estimated digit. The greater the number of significant figures, the greater the certainty with which the value is known.
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Conversion Factor
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Fraction in which the numerator is equivalent to the denominator, but is expressed in different units, making the fraction equivalent to 1.

initial units * (desired units/initial units)

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Absolute Zero (O K)
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Zero point on Kelvin temperature scale; theoretically the lowest temperature possible.
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Fahrenheit to Celsius Conversion
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C = (5/9)[(F)-32]
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Celsius to Kelvin
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K = C + 273.15
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Extensive Property (dependent)
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Depends on how much matter is considered. Mass, length, and volume
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Intensive Property (independent)
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Independent of the amount of matter considered. Temperature and density
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Sig Figs (Addition and Subtraction)
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Lowest number of Sig Figs after decimal for your answer
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Sig Figs (Multiplication and Division)
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Answer has same number of sig figs as least sig fig number in equation.
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Sig Fig (Mixed)
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Solve the problem with all known digits, and then use the Multiplication and Division rule.

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