Flashcards in Ch 2 Section 2 Deck (59):

1

## Measurements represent

### Quantities

2

## A quantity is something that has

### Magnitude, size, or amount

3

## Quantity is not the same as a

### Measurement

4

## Units of measurement compare

### What is to be measured with a previously defined size

5

## Nearly every measurement is a

### Number plus a unit with choice of unit depending on quantity being measured

6

## SI

###
Le systéme international d'Unités

Measurement system agreed on by scientists all over the world

7

## SI system adopted in

### 1960 by General Conference on weights and measures

8

## SI has

### 7 base units with most other units derived from these 7

9

## SI units are defined in terms of

### Standards of measurement

10

## Standards are objects or natural phenomena that are of

###
Constant value

Easy to preserve and reproduce

Practical on size

11

## Numbers are written in a form that is

### Agreed upon internationally

12

## Prefixes added to names of SI units represent

### Quantities that are larger or smaller than the base units

13

## Centi

###
1/100

14

## 1 cm

### 1/100 of a meter

15

## SI standard unit for mass is

### Kilogram

16

## Gram

### 1/1000 of a kg

17

## Gram is more

### Useful for measuring masses of Small objects

18

## For even smaller objects (measuring mass)

### Milligram is used

19

## 1 mg

### 1/1000 of a gram

20

## Mass is determined by

### Comparing mass of an object with a set of standard masses that are part of the balance

21

## Measurements are

### Quantitative information.

22

## Weight is a measure of the

### Gravitational pull on matter

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## Weight is typically measured on a

### Spring scale

24

## As the force of gravity on an object increases

### Weight increases

25

## SI standard unit for length is

### Meyer

26

## 1 km

### 1000 m

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## To express shorter distances the

### Cm is often used

28

## Combinations of SI units form

### Derived units

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## Derived units are produced by

### Multiplying or dividing standard units

30

## Pascal

### kg/ m x s^2

31

## Prefixed can also be added to express

### Derived units

32

## Volume is the amount of

### Space occupied by an object

33

## Derived SI unit of volume is

### m^3

34

## One m^3=

### Volume of a cube whose edges are 1 m long

35

## The cm^3 is often used to

### Express the volume of materials in a chem lab

36

## m^3=

### 1000000 cm^3

37

## When chemists measures volumes of liquids and gases they often use

### A non SI unit called the liter

38

## Liter=

### 1 decimeter cubed

39

## 1 liter =

### 1000 cm cubed

40

## 1000 mL=

### 1 L

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## mL and cm^3 are

### Interchangeable

42

## Density

###
Ratio of mass to volume

Mass/volume

43

## SI unit for density is derived from

###
Base units for mass and volume- kg and m^3- and can be expressed as

kg/m^3

44

## Density is often expressed as

### g/ cm^3 it g/mL

45

## Densities of gas are generally expressed as

### kg/m^3 or g/L

46

## Density is a characteristic

### Physical property of a substance

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## Density doesn't depend on the size of the same because

### As the samples mass increases, it's volume increases proportionately, and the ratio of mass to volume is constant

48

## Density can be used as

### A property to help identify a substance

49

## Density varies with

### Temperature

50

## Most objects expand as temperature increases thereby

### Increasing in volume

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## Density usually

### Decreases with increasing temperature

52

## A conversion factor is a

### Ratio derived from the equality between two different units that can be used to convert from one unit to the other

53

## Each conversion factor equals 1 because the

### 2 quantities divided in any conversion factor are equivalent to each other

54

## Because conversion factors are equal to 1 they can be multiplied by other factors in equations

### Without changing the validity of the equations

55

## Dimensional analysis

### Mathematical technique that allows you to use units to solve problems involving measurements

56

## Quantity sought =

### Quantity given x conversion factor

57

## It is always best to begin with an idea

### Of the units you will need in your final answer

58

## Conversion factors can be derived if you know the

### Relationship between the unit you have and the unit you want

59