Chapter 1 Study Of Chemistry Flashcards
(53 cards)
Matter:
Anything that has mass and occupies space. Made of atoms-the smallest particle of an element that retains chemical nature of the element.
Molecules
Two or more atoms chemically joined
The scientific Method
Observations
Hypothesis: a tentative explanation or interpretation. Must be testable.
Experiment: highly controlled set of procedures to generate more data or observations.
Scientific law:
Generalization about past observations from which future predictions can be made.
Examples:
Law of gravity/law of conversation of matter/ Newton’s law is motion/ law of thermodynamics
Scientific Theory:
An explanation of an observation or law. Theories can only be validated. Never prove a theory 100%.
Examples:
Theory of gravity/ Evolutionary Theory/ Big Bang Theory/ Cell theory
Measurements: international system d’unites
Length: meter,m Mass: kilograms, kg Time: seconds, s Temperature: kelvin, k Amount: mole, mol
Derived units
Volume
Density
Velocity
Force
Length
Distance traveled by light in a vacuum in a give time period.
1m=39.37 in
Volume
Amount of space occupied by an object
SI Unit: 1m^3= 1000L
1mL=1cm^3=1cc
Mass
The amount of matter in an object kilogram
Weight
A measure of the gravitational pull exact on an object
1kg=2.205lbs
Density
Mass/volume
Examples
g/cm^3=g/ml
Kg/L
Time
Cs-133 frequency of the emitted radiation
Temperature
A measure of the average kinetic energy in a system. Energy of motion.
Significant figures
Digits in a measurements which contain digits and one digit of uncertainty
Digital instruments
Record all digits shown on the display
Analog instruments
10% rule: in reading measurements the uncertainty should be 10% of the instrument increments
Buret
Glassware used to measure delivered volume
Rules of sig. figs.
- All non zeros are significant
- Zeros between no zeros are significant
- Leading zeros are never significant
- Trailing zeros right of a decimal are significant
- Trailing zeros before an implied decimal are not significant
- Counting numbers and define numbers have an infinite number of sig. dig. (No uncertainty)
Scientific notation
A way of expressing numbers as a number between 1 and 10 times 10 raised to some power
Positive exponent: large number- move decimal to right
Negative exponent: small numbers- move decimal to left
Metric prefixes
Kilo, k:1000 Centi, c:0.01 Milli, m:0.001 Micro, μ: 0.000001 Nano, n:0.000000001
Division/multiplication
The answer cannot have more sig. figs. Then any of the original numbers
Choose the smallest
Addition/subtraction
The answer cannot have more digits after the furthest left uncertain digit of any of the original numbers
Precision
How close a set of data are to each other reproducibility
