Semester Exam Vocabulary Flashcard

Scientific Method


the solution to a scientific problem:

State the Problem


Create a hypothesis

Carry out an experiment


Draw a conclusion

(you can then redo the experiment to make sure results are accurate)

in other words, PRHED/OC

an explanation to an observation
procedure used to test a hypothesis
independant variable
variable that you can change during the experiment
Dependant Variable
variable that is oberved during the experiment
Scientific Theory
explains natural phenomenon based on large body of evidence
Scientific Law
concise statement that summarizes the results of many observations and experiments; generally accepted but can be disproven with out explanation
amount of matter an object holds
measure of the amount of space an object holds
extensive property

property of matter that depends on the amount of matter in a sample

examples include: mass, volume, surface area, heat and absorbed light

intensive  physical property

property that depends on the type of matter in a sample, and can identify unknown samples and describe the sample on ITS OWN


density, color, solubility, hardness

physical property of a substance
quality or condition that can be measured or observed without changing the composition
Physical Change

some properties of the matter change but the composition does not change;

can be classified as irreversible or reversible changes


physical blend of two or more components;

can be classified as heterogenous mixtures or homogenous mixtures

Heterogenous Mixture

the composition is not uniform throughout

(think of chex mix)

Homogenous mixture

the composition is uniform throughout

(another name for this is a SOLUTION)

simplest form of matter with its unique set of properties

two or more elements chemically combined in a fixed proportion;

REMEMBER: compounds can be broken down chemically into simpler substances but elements cannot

Chemical Change
change that produces matter with a different composition than the original matter
Summary of classifying matter


substance                                     mixture

element/compound              homo/hetero

chemical property

ability of a substance to undergo a specific chemical change;

ex: iron combines with oygen to form rust so rusting is a chemical property of iron

Clues of a chemical change

transfer of energy

color change

gas production

formation of a precipate

law of conservation of matter
matter can never be created or destroyed. it simply changes from one form to another.
Difference between accuracy and precision

accuracy: measure of how close a measurement comes to the true value

precision: measure of how close a series of measurements are to one another

** if accurate but not precise, there is a technical error/human error

*** if precise but not accurate, there is a problem with the instrument/mechanical error

How to calculate percent error
exp. value-true value/true valueX 100
SI System

meter- length (m)

kilogram-mass (kg)

kelvin-temperature (K)

second-time (s)

mole-amount of substance (mol)

candela-luminous intensity (cd)

ampere-electric current (A)

Common units of energy
Joule (J) and calorie (cal)

intensive property that depends only on the composition of a substance, not the amount


formula: mass / volume



smallest particle of an element that retains its identity in a chemical reaction

SI system prefixes– add meaning to the base units


Giga (G) 1,000,000,000

Mega (M) 1,000,000

kilo (k) 1,000

hecto (h) 100

deca (da) 10

deci (dc) 0.1 or one tenth

centi (c) 0.01 or one hundreth

milli (m) 0.001 or one thousandth

micro (weird m) 1/1,000,000

nano (n) 1/1,000,000,000


Mass vs. Weight

mass- measured with a balance and does not depend on gravity


weight- measured with a scale, not used in chemistry and depends on gravity

Law of conservation of energy
energy can neither be created nor destroyed. it simply changes from one form to another.
intensive chemical reaction

property that doesnt matter on amount of sample, can identify unknowns and can describe how the sample reacts in a chemical reaction


reactions with acids


Different forms of a pure element with different properties

carbon allotropes:

coal, diamond, graphite, charcoal

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