CHEMISTRY I- CHAPTER 2 Flashcards
STUDY
What is a base unit
a defined unit in a system of measurent that is based on an object or event
What is the base unit of time
second
second = ?
defined at the frequency of the radiaton of celsium -133
base unit of lenght
meter
meter = ?
the distance the light travles in a vacuum in 1/299,792, 458 of a second
base unit of mass
kilogram
kilogram= ?
the cilinder of Pt and Ir kept in France
base unit of temperature
kelvin
kelvin
0 K where all the particles were all their lowest possible energy state
why kelvin does not have the °
because it is an absolute value number, it cant be negative
Fahrenheit
(°C * 9/5) + 32
Celsius
(°F - 32) * 5/9
Kelvin
C + 273.15
what is a derived unit
a unit that is defined by a combination of base units.
volume
the space ocuppied by an object
liter
equal to one cubic decimeter (dm3) . 1L = 1dm3
density
physical property of matter used to identity element.
mass divided by volume
scientific notation
used to express really big or small numbers ( 1 * 10 a la a)
dimensional analysis
system aproach to problem solving that uses conversion factors to move, or convert, from one unit to another.
conversion factors
a ratio of equivalent values having different units
accuracy
how close a measured value is to an accepted value
precision
how close a series of measurents are to one another
error
the difference between an experimental value and an accepted value
percent error
expreses error as a precentage of the accepted value
significant figures
reported digits, include all know digits plus one estimated digit
2 things a conversion factors should accomplish
- it must cancel one unit and introduce a new one.
- all the units except the desire unit must cancel
