The properties of matter must be measured correctly and reported without ambiguity Value A quantities description that includes both a number and a unit Units quantities defined by standards that people have agreed to use to compare one eventobject to another ID: 421924
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Slide1
Measurements and units
The properties of matter must be measured correctly and reported without ambiguity. Slide2
Value- A quantities description that includes both a number and a unit
Units- quantities defined by standards that people have agreed to use to compare one event/object to another
Breakdown of MeasurementSlide3
The Customary system was based on:
Inch (unit) = width of average thumb (standard)
Foot = typical length of an adult foot (which varied)
Metric system
Created by the French in the 18th CenturyConsistent and systematic set of standards
Old v. New Measurement Slide4
Meter (Greek metron
,
“a measure”)
Originally one ten-millionth of the distance from the North pole to the equator
Today it is defined as the distance light travels in 1/299,792,458 secondEvolution of the Metric SystemSlide5
A modern elaboration of the original metric system, was set up in 1960
Base units- Units from which all other units are derived
International Syste
mSlide6
Many properties can not be described directly with one of the seven SI base units
Volume- Length cubed (cubic meters)
A meter is often inconveniently large
A liter (L) is 1/1000 of a meter
1 L =
or
L = 1
SI Units Derived from Base UnitsSlide7
IllustrationSlide8
SI base units and derived units are
not always a convenient size for making
measurements
A way deriving new units that are larger and smaller has been developed
Scientist attach prefixes to base units which multiply and divide a base unit by a power of 10
SI Units Derived from Metric PrefixesSlide9
Kilometer =
meter
Kilo =
(3,000)
To abbreviate combine abbreviated prefix with abbreviated unit
Kilo
is k
Meter is
m
1 km =
ExamplesSlide10
Table of PrefixesSlide11
Range of LengthsSlide12
Range of VolumeSlide13
Mass is the measure of the amount of matter in an object
Matter is anything that has mass and takes up space
Weight is a measure of the force of gravitational attraction between it and a significantly large body
Mass and VolumeSlide14
An objects weight on the surface of a celestial body (i.e. Earth) depends on its mass and on the distance between it and the center of a celestial body.
Mass is also defined as the property of matter that leads to gravitational attractions between objects; this always gives rise to weight
In SI system mass is described by units such as kilogram, milligram and gram
Mass’s Relationship with EarthSlide15
Mass is a constant and will remain the same
As the distance between an object and its celestial body increases its weight decreases
Weight is actually the measure of the
force
of gravitational attraction for a body, it can be described with force unitsSI unit newton, NWeight is not really a concern of Chemist, therefor it won’t be mentioned much in Chemistry
Weight v. Mass Slide16
Range of MassSlide17
Temperature- measure of the average motion of particles in a system
3 most common Units of Measurement
Celsius
0
is freezing point of
100
is the boiling point
Fahrenheit
32
is freezing point of
; 212
is the boiling point
Kelvin
0 K is
absolute zero
; which is the lowest possible temperature
TemperatureSlide18
The temperature of an object is a measure of the degree of motion of its particles
As the motion decreases; the temperature of an object decreases
Absolute zero is the point beyond which the motion of the particles, and therefor the temperature cannot be decreased
Therefor all Kelvin temperatures are positive
Deeper look at KelvinSlide19
TemperatureSlide20
Reporting Values and measurements
Section 1.5Slide21
Precision describes how closely a series of measurements of the same object resemble each other
The closer the measurements the more precise
Accuracy describes how closely a measured value approaches the true value of the property
ALL
calculations have an uncertainty of
unless stated otherwise
Accuracy and PrecisionSlide22
Sometimes it is necessary to use trailing zeros to show the uncertainty
The accuracy or uncertainty are often showed on the device of measuring
Reporting MeasurementsSlide23
Define all of the terms in the chapter
Describe how science is general is done
Use the SI base units and their abbreviations to describe length, mass, time, temperature, and volume
Describe the relationship between liters and cubic meters
State the numbers of fractions represented by the following metric prefixes, and write their abbreviations:
gigi
, mega, kilo,
centi
,
milli
, micro,
nano, and picoDescribe the relationships between the metric units that do not have prefixes (such as meter, gram, and liter) and units derived from them by the addition of prefixes.Assignment and Objectives