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the science that deals with the materials of the universe and the changes that these materials undergo;
the study of matter |
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Term
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Definition
Observation: qualitative or quantitative (measurement involving a number)
Hypothesis: a possible explanation for the observation
Experiment: testing the hypothesis
Theory - - - Law
A law tells what happened; a theory (model) is our attempt to explain why it happens
Theory: a set of tested hypotheses that gives an overall explanation of some part of nature; an interpretation
Law: a summary of observed (measurable) behavior |
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Steps used to solve problems
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Definition
1. recognize the problem and state it clearly
making an observation
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Definition
a set of tested hypotheses that gives an overall explanation of some part of nature
an observation is something that is witnessed and can be recorded. A theory is an interpretation - a possible explanatino of why nature behaves in a particular way |
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Definition
A law is a summary of observed behavior; whereas a theory is an explanation of behavior.
A law tells what happened; a theory (model) is our attempt to explain why it happened |
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measurement =
quantitive observation |
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Definition
| must always consist of a number and a unit |
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Definition
simply expresses a number as a product of a number between 1 and 10 and the appropriate power of 10.
93,000,000 = 9.3 x 10^7
the number of places the decimal point is moved determines the power of 10; the direction of the move determines whether the power of 10 is positive (left) or negative 9 (right) |
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| part of a measurement that tells what scale or standard is being used to represent the results of the measurement |
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Definition
mass kilogram kg
length meter m
time second s
temperature kelvin k |
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| fundamental SI unit of length |
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Definition
1 m = 39.37 in
1 in = 2.54 cm |
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the amount of three dimensional space occupied by a substance
the quantity of matter present in a object
1 L = 1000 mL
1 kg = 1000 g
0.001g = 1 mg
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Every measurement has some degree of uncertainty
The numbers recorded ina measurement (all the certain numbers plus the first uncertain number) are called significant figures
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Definition
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| rules for counting significant figures |
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Definition
Non zero integers ALWAYS count as significant figures
Leading zeros are are zeros that precede all of the nonzero digits. They NEVER count as significant; they simply indicate the position of the decimal point.
Captive zeros are zeros that fall between nonzero digits. They ALWAYS count as significant figures.
Trailing zeros are zeros at the right end of the number; They are only significant if the number is written with a decimal point.
Exact numbers NEVER LIMIT the number of significant figures in a calculation. |
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| rules for using significant figures in calculations |
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Definition
For multiplication and division, the number of significant figures in the result is the same as that in the measurement with the smallest number of significant figures. LIMITING
For addition and subtraction, the limiting term is the one with the smalles number of decimal places. |
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Conversion factor
Equivalance statement
dimensional analysis |
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Definition
a ratio of the two parts of the statement that relates to two units
1 in = 2.54 cm
the respective numbers are different because they refer to different scales
Changing from one unit to another via conversion factors (based on the equivalance statements between the units) |
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Term
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Definition
Freezing and boiling points
(the difference is 100 on both scales)
Fahrenheit 32 212
Celsius 0 100
Kelvin 273 373
TK = TC + 273
TC = TK - 273
TF = 1.80 (TC) + 32
TC = TF - 32 / 1.80
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Definition
the amount of matter present in a given volume of substance
D = mass / volume in g/mL or g/cm^3
the device used to test the density of a solution is a hydrometer |
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Definition
the density of a liquid;
the ratio of a given liquid to the density of H2O at 4C |
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Definition
the stuff of which the universe is composed; has two characteristics: it has mass and occupies space
States of matter:
SOLID - has fixed shape and volume
LIQUID - has definit volume but takes shape of its container
GAS - has no fixed volume or shape
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physical properties
chemical properties |
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Definition
odor, color, volume, state (solid, liquid, gas), density, melting point, and boiling point
its ability to form new substances |
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Definition
| the decomposition of water by an electric current, a chemical proces |
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physical change
chemical change |
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Definition
involves a change in one or more physical properties, but no change in the fundamental components that make up the substance. The most common physical changes are changes of state.
involves a change in the fundamental components of the substance; a given substance changes into a different substance or substances. Chemical changes are called reactions: silver tarnishes |
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Elements
Compounds
Mixture
Pure substance |
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Definition
a substance that cannot be broken down into other substances by chemical methods
a substance composed of a given combination of elements that can be broken down into those elements by chemical methods. A compound always has the same composition.
something that has variable composition; can be separated into pure substances: elements and/or compounds
will always have the same composition; either elements or compounds |
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homogeneous mixture / solution
heterogeneous mixture |
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Definition
is the same throughout
contains regions that have different properties from those of other regions |
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Definition
the separation process; physical method with no chemical change
separates a liquid from a solid; physical method
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