Chapter 3 Lesson 2: Units of Measurement Flashcards
What makes metric units easy to use?
All metric units are based on multiples of 10. As a result, you can convert between units easily.
SI unit of Length
Meter (m)
SI unit of Mass
Kilogram (kg)
SI unit of Temperature
kelvin (k)
SI unit of time
Second (s)
SI unit of (amount of substance)
Mole (mol)
Mega
Symbol: M
Meaning: 1 million times larger than the unit it precedes
Factor: 10 to the power of 6
kilo
Symbol: k
Meaning: 1000 times larger than the unit it precedes
Factor: 10 to the power of 3
deci
Symbol: d
Meaning: 10 times smaller than the unit it precedes
Factor: 10 to the power of -1
centi
Symbol: C
Meaning: 100 times smaller than the unit it precedes
Factor: 10 to the power of -2
milli
Symbol: m
Meaning: 1000 times smaller than the unit it precedes
Factor: 10 to the power of -3
SI unit of (volume)
cubic meter
Liter
Symbol: L
Relationship: base unit
Milliliter
Symbol: mL
Relationship: 1000 mL = 1 L
divide by 1000 to get liter
Cubic centimeter
Symbol: cm3
Relationship: 1 cm3 = 1 mL
multiply by 1000
gram (g)
1/1000 of a kilogram
Kilogram (base unit)
Symbol: kg
Relationship: 1 kg = 1000 g
Gram
Symbol: g
Relationship: 1 g = 10 to the power of -3 kg
milligram
Symbol: mg
Relationship: 1000mg = 1 g
Weight
is a force that measures the pull on a given mass by gravity.
Weight, a measure of force, is different from mass, which is a measure of the quantity of matter.
The weight of an object can change with its location.
energy
The capacity to do work or to produce heat
The SI unit of energy
joule (J)
calorie (cal)
One calorie (cal) is the quantity of heat that raises the temperature of 1 g of pure water by 1°C.
1 Joule
= 0.2390 cal
1 calorie
= 4.184 J
temperature scales
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What temperature units do scientists commonly use?
Scientists commonly use two equivalent units of temperature, the degree Celsius and the kelvin.
Temperature
is a measure of how hot or cold an object is.
An object’s temperature determines the direction of heat transfer.
When two objects at different temperatures are in contact, heat moves from the object at the higher temperature to the object at the lower temperature.
Celsius scale
sets the freezing point of water at 0°C and the boiling point of water at 100°C.
Kelvin scale
the freezing point of water is 273.15 kelvins (K), and the boiling point is 373.15 (K).
The zero point on the Kelvin scale, 0 K, or absolute zero, is equal to –273.15°C.
…………………
converting kelvin to celsius
k= c + 273 c = k - 273
What determines the density of a substance?
Density is an intensive property that depends only on the composition of a substance, not the size of the sample.
Relationship of density.
The relationship between an object’s mass and its volume tells you whether it will float or sink.
This relationship is called density
Density
is the ratio of the mass of an object to its volume.
The SI unit of density
kilograms per cubic meter (kg/m3).
Density = mass/volume
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