CH 1 & 2 Flashcards
What is composed of chemicals?
virtually everything
What composes all common matter?
atoms and molecules
What are molecules composed of?
atoms
What are the attachments that hold atoms together?
chemical bonds
What common things do chemicals compose?
air, water, toothpaste, tylenol, toilet paper
What are some things chemicals do not compose?
sunlight (energy)
What does chemistry explain?
the properties and behaviors of chemicals
All things are made of what?
atoms or molecules
True or false, this is the simple defenition of chemistry: the science that tries to understand how matter behaves by studying how atoms and molecules behave
True
True or false, this is the definition of scientific method: a way of learning that emphasizes observation and experimentation - to produce knowledge as the result of sense
True
scientific method stands in contrast to what?
Greek philosophies
What are the greek philosophies?
reason to produce knowedge as the result of thoughts
Define laws
summarizes the results of a large number of observations
Define theories
models that explain and give the underlying causes for observations and laws
What are observations?
involving measuring or observing some aspect of nature
What are hypotheses?
tentative interpretations of the observations
What must be validated by experiment?
hypotheses, laws, and theories
What happens if hypothesis are not confirmed?
they are revised and tested through further experimentation
How do we recognize observations?
some can be seen with the naked eye, they emerge from experiements, usually involve the measurement or description
What is the mass of an object?
the measure of the quantity of matter
Combustion means…
burning
What does weight take into account?
gravity
When measuring the mass of a container and its contents before and after burning the substance what happens?
No change in the mass happens during combustion
True or false: a good hypothesis is falsifiable?
True
What are experiments?
highly controlled observations designed to validate or invalidate hypotheses
What happens to a new hypothesis?
must also be tested through further interpretation
What is a scientific law?
a breif statement that synthesizes past observations and predicts future ones
What is the law of conservation of mass?
“In a chemical reaction, matter is neither created nor destroyed”
What forms the basis for a scientific theory?
one or more well-established hyppotheses
What provides a broader and deeper explanation for observations and laws?
theories
What are models are the way of nature?
theories
What predicts behavior that extends well beyond the observations and laws on which they are founded?
Theories
How are scientific theories tested and validated?
by experiments
What happens to a hypothesis, law, or theory if it is inconsistent with the findings of an experiment?
must be revised and new experiments must be conducted to test the revisions
What happens over time to theories?
poor theories are eliminated, and good theories (those consistent with experiments) remain
Who and what is the atomic theory?
John Dalton created it, “all matter was composed of small, indestructible particles called atoms
What was Dalton’s theory?
model of the physical world
What are the most powerful pieces of scientific knowledge?
established theories with strong experimental support
Well-tested theories are as close to ___ as we get in science
truth
What is quantification?
measurement as part of observation ** one of the most important tools
What does quantification allow?
allows you to specify the difference precisely
What must you do in chemistry class?
do your work regularly and carefully, requires commitment, calculations
What is a decimal part?
a number that is between 1 and 10
What is an exponential part?
10 raised to an exponent, n
In sig figs where is the uncertainty?
in indicated by the last reported digit
the greater the precision of the measurement, the greater the number of _____?
significant figures
All nonzero digits are….
significant
interior zeros (zeros between two numbers) are…
significant
trailing zeros (zeros to the right of a nonzero number) that fall after a decimal point are…
significant
trailing zeros that fall before a decimal point are…
significant
leading zeros (zeros to the left of the first nonzero number) are …
NOT significant
trailing zeros at the end of a number, but before an implied decimal point, are …
ambiguous
exact numbers have how many sig figs?
unlimited
How many sig figs in each?
0.0035
1.080
2371
2.97 x 10^5
1 dozen = 12
100.00
100000
2
4
4
3
infinite
5
ambiguous
When multiplying, how many sig figs do you keep?
the lowest number of sig figs and when its time to round
In additions and subtraction how many sig figs do you keep?
same # of decimal places as the lowest number of decimal places
What are SI Units?
International system of units
The kilogram is a measure of what?
mass
the mass of an object is the measure of the …?
quantity of matter within it
the weight of an object is the measure of the …?
gravitational pull on that matter
When measuring you should pick a unit similar in what?
size to or smaller than the quantity
units are multiplied, divided and canceled just like…?
any other algebraic quantities
using units as a guide to solving problems is called?
dimensional analysis
always write every number with its associated…?
unit
always include … in your calculations?
units
density =
mass/volume
