Ch 3.2 and 2.4 Flashcards
0
Q
Derived Units
A
- Carefully defined and can be derived from other base units
1
Q
Base Units
A
- Carefully defined and cannot be derived from other units
2
Q
Units before Metric System
A
- First known units: Indus Valley Civ.
- Egyptian length: Cubit
- Taking measurement was not possible without units
- Developing units made trade and commerce possible
- Developing universally understood units was difficult
- Units that did not work: Virgate, League, Rood, Jigger, Jack, Grain
3
Q
In order to be unit, it must be….
A
- Clearly defined
- Reproducible
- It’s meaning will not change with time
- Easy to understand & convert between similar units
4
Q
Metric System background
A
- 1791: French Academy of Scientist made Metric system
- Went into use in 1795
- Defined meter as 1/10000000 of the distance between Dunkirk and Barcelona
- Created platinum bar for other meters to be compared
5
Q
Tera
A
- 10 to the 12th
- Symbol: T
6
Q
Giga
A
- 10 to the 9th
- Symbol: G
7
Q
Mega
A
- 10 to the 6th
- Symbol: M
8
Q
Kilo
A
- 10 to the 3rd
- Symbol: k
9
Q
Hecto
A
- 10 to the 2nd
- Symbol: h
10
Q
Deca
A
- 10 to the 1st
- Symbol: da
11
Q
No prefix means…
A
-One
12
Q
Deci
A
- 10 to the -1
- Symbol: d
13
Q
Centi
A
- 10 to the -2
- Symbol: c
14
Q
Milli
A
- 10 to the -3
- Symbol: m
15
Q
Mirco
A
- 10 to the -6
- Symbol: upside-down h)
16
Q
Nano
A
- 10 to the -9
- Symbol: n
17
Q
Pico
A
- 10 to the -12
- Symbol: p
18
Q
What/ how was the Metric System revised?
A
- 1960: Metric System becomes SI system
- Meter became 1/ 299792458 seconds (distance light travels to be 1 meter)
- Created base units
19
Q
7 Base Units during SI System
A
- Length: Meter (m)
- Mass: Kilogram (kg)
- Time: second (s)
- Electric current: ampere (A)
- Temperature: kelvin (K)
- Amount of substance: mole (mol)
- Luminous intensity: candela (cd)
20
Q
Criticism of the SI System
A
- Derived units are not convenient size
- Base unit for mass= kilogram, which makes people thing that gram is the base unit.
21
Q
Volume
A
- The space in which an object occupies
- L x W x H
22
Q
Liter
A
- Non- SI unit
- 1,000 cm cubed is 1 Liter
23
Q
Weight
A
- a force that measures the pull on a given mass by gravity
- effected by gravity
24
calorie
- cal
| - Quantity of heat that raises the temperature of 1 g of water by 1 degree C
25
Temperature
- The measure of how hot or cold an object is
| - When 2 objects come in contact heat moves from the object of higher temp to the one of lower temp
26
Celsius scale
- Freezing point : 0
| - Boiling point: 100
27
Kelvin scale
- Freezing point: 273.15
| - Boiling: 373.15
28
Absolute 0
- On the Kelvin scale
- When molecules almost stop moving, but don't
- Equal to -273.15 C
29
Formula to turn Celsius into Kelvin
K= C+ 273
30
Formula to turn Kelvin into Celsius
C= K - 273
31
Density formula
Density= Mass/ Volume
32
Volume formula
Volume= L x W x H
33
Something will float on something else if...
-Its density is less than what it is floating on
34
Four signs of a chemical change
- Transfer of Energy
- Formation of Precipitate
- Gas production
- color change
35
Solid
- Rigid
- fixed shape
- fixed volume
- cannot be flattened
36
Liquid
- not rigid
- no fixed shape
- fixed volume
- Cannot be flatted
37
Gas
- Not rigid
- No fixed volume
- No fixed shape
- Can be flattened
38
Exothermic reaction
-A chemical reaction that releases energy in the form of light or heat
39
Endothermic Reaction
-A chemical reaction that absorbs energy
