chapter 1: introduction to chemistry Flashcards by Gail I

chemistry: study of matter and its interactions with

other matter and with energy

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foundation of chemistry is

experimentation

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chemistry is an experimental science in which we derive knowledge from

carefully planned and performed experiments

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to formulate ideas for experiments, scientists draw on

experience, using experimental data and theory

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hypothesis is a possible

explanation for an event

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law: a statement that can summarize

a large number of observations

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theory: an explanation of

the laws of nature

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theories are subject to change when

new data becomes available

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matter: anything with

mass and volume

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mass: amount of

matter in an object

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weight: force of …. between a particular object and ….

attraction; another object

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weight is also the measure of the

gravitational pull on an object

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balance to measure

mass

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scale to measure

weight

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property: observations or

measurements regarding matter

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physical properties: properties that can be measured without

changing the composition of the sample

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examples of physical properties:

mass, volume, color, phase

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chemical properties: describe

reactivity of a material

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examples of chemical properties:

explosiveness, flammability, lack of reactivity

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physical change: does not change the

composition/ identity of a substance

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examples of physical change

freezing, melting, boiling

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chemical change: involves the transformation of matter into

different substances

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examples of chemical change

rusting, burning

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extensive properties: depend on the

size of the sample

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extensive properties measure how much ... is in a particular sample

matter

examples of extensive properties:

mass, volume

intensive properties: not dependent on the

size of the sample

intensive properties depend on

what the sample is

examples of intensive properties:

colors, melting points, densities

intensive properties can be used to

identify a substance

substance: chemically the

same throughout

element: cannot be broken down into

simpler, stable substances

compound: can be

broken down into simpler, stable substance

matter can be classified by:

chemical composition, physical state, color, etc.

compounds are uniform in

composition and properties throughout

mixture: matter that can be separated into two or more substances by differences in the

physical properties of the components

homogenous mixture:

uniform in composition

examples of homogenous mixtures:

sugar-water solution, air

heterogenous mixtures:

not uniform in composition

examples of heterogenous mixtures:

mixture of iron and sand, vegetable soup, salt and pepper

samples of the same mixture can have different ..., unlike ...

compositions; substances

alloy: a solid solution that consists of a

metal and another substance, usually another metal

substance: matter that cannot be separated into

component parts by a physical process

compounds: substances that can be decomposed into simpler substances or into their elements by

chemical processes

compounds always contain the same elements in the

same proportions

all samples of a compound have the same

intensive properties

symbols for the elements are abbreviations for their

names

numerical measurements have 4 aspects:

object, value; units; reliability

reliability:

accuracy and precision

accuracy: expresses how close a measurement is to the

correct or accepted value

precision: refers to the closeness of a set of measurements to

each other, but not necessarily the accepted value

accurate: number has a small

error

precise: number has small

uncertainty

significant figures: used to display the

uncertainty of results

significant figures: all digits known with certainty, plus one more digit that is

not certain

uncertainty of final digit is

± 1

nonzero digits are

significant

zeros between nonzero digits are

significant

with no decimal point to the right of a zero, the trailing zero may or may not be

significant (clarified by scientific notation)

if there is a decimal point, leading zeros are ..., but zeros at the end of the number are ...

insignificant; significant

number of sig figs in a calculated value results from the... of the ...and the ...that were used to attain the final value

uncertainties; measurements; operations

addition/subtraction sig figs: answer has the same number of decimal places as the component with the

least number of decimal places

multiplication/division sig figs: answer has the same number of sig figs as the component with the

least number of significant digits

(rounding rules) if digit after the last sig fig is

round down

(rounding rules) if digit after the last sig fig = 5,

round to even

(rounding rules) if digit after the last sig fig is > 5

round up

density: ratio of

mass to volume

three kinds of numbers never limit sig fits:

counted numbers/tallies, defined numbers, power of ten

quantities: describe... and illustrate ...

properties; precise information

units: standards by which

measurements are compared

SI units: 7 base units which define

length, mass, time, temperature, amount of substance, electrical current, luminous intensity

length:

meter

mass:

kilogram

time:

second

temperature

kelvin

amount of substance:

mole

electrical current:

ampere

luminous intensity:

candela

base units can be

reproduced in labs (exception: kilogram)

derived units: physical quantities that can be expressed as a

combination of base units

when multiplying by conversion factors, the ... are what change, along with the ....

units; numeric value

(prefixes) yotta- Y

10^24

(prefixes) zeta- Z

10^21

(prefixes) exa- E

10^18

(prefixes) peta- P

10^15

(prefixes) tera-T

10^12

(prefixes) giga-G

10^9

(prefixes) mega- M

10^6

(prefixes) kilo- k

10^3

(prefixes) hecto- h

10^2

(prefixes) deka- da

10^1

(prefixes) deci- d

10^-1

(prefixes) centi- c

10^-2

(prefixes) milli- m

10^-33

(prefixes) micro- µ

10^-6

(prefixes) nano- n

10^-9

(prefixes) pico- p

10^-12

(prefixes) femto- f

10^-15

(prefixes) atto- a

10^-18

(prefixes) zepto- z

10^-21

(prefixes) yocto- y

10^-24

unit conversion factor: fraction in which the numerator is a quantity that is equal or equivalent to the quantity in

the denominator but expressed in different units

to know what conversion factor should be used, determine which units should be ... and which units you are attempting to ...

canceled; attain

standard unit for volume is

m^3

density is a ... property that can help

physical; identify substances

density can't be used to convert between

different substances

standard unit for density:

kg/ m^3

none of the relationships between the English and SI units is ...; effects ...

exact; sig figs

conversion factors between Celsius and Fahrenheit

``` TF = TC x (1.8℉/1.0℃) + 32 ℉ TC = (TF - 32 ℉) x (1.0℃/1.8℉) ```

absolute zero:

-273.15 degrees C

conversion between Celsius and kelvin:

Tk = Tc + 273.15