Ch 2 Section 2 Flashcards Preview

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Flashcards in Ch 2 Section 2 Deck (59)
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1
Q

Measurements represent

A

Quantities

2
Q

A quantity is something that has

A

Magnitude, size, or amount

3
Q

Quantity is not the same as a

A

Measurement

4
Q

Units of measurement compare

A

What is to be measured with a previously defined size

5
Q

Nearly every measurement is a

A

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

6
Q

SI

A

Le systéme international d’Unités

Measurement system agreed on by scientists all over the world

7
Q

SI system adopted in

A

1960 by General Conference on weights and measures

8
Q

SI has

A

7 base units with most other units derived from these 7

9
Q

SI units are defined in terms of

A

Standards of measurement

10
Q

Standards are objects or natural phenomena that are of

A

Constant value
Easy to preserve and reproduce
Practical on size

11
Q

Numbers are written in a form that is

A

Agreed upon internationally

12
Q

Prefixes added to names of SI units represent

A

Quantities that are larger or smaller than the base units

13
Q

Centi

A

1/100

14
Q

1 cm

A

1/100 of a meter

15
Q

SI standard unit for mass is

A

Kilogram

16
Q

Gram

A

1/1000 of a kg

17
Q

Gram is more

A

Useful for measuring masses of Small objects

18
Q

For even smaller objects (measuring mass)

A

Milligram is used

19
Q

1 mg

A

1/1000 of a gram

20
Q

Mass is determined by

A

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

21
Q

Measurements are

A

Quantitative information.

22
Q

Weight is a measure of the

A

Gravitational pull on matter

23
Q

Weight is typically measured on a

A

Spring scale

24
Q

As the force of gravity on an object increases

A

Weight increases

25
Q

SI standard unit for length is

A

Meyer

26
Q

1 km

A

1000 m

27
Q

To express shorter distances the

A

Cm is often used

28
Q

Combinations of SI units form

A

Derived units

29
Q

Derived units are produced by

A

Multiplying or dividing standard units

30
Q

Pascal

A

kg/ m x s^2

31
Q

Prefixed can also be added to express

A

Derived units

32
Q

Volume is the amount of

A

Space occupied by an object

33
Q

Derived SI unit of volume is

A

m^3

34
Q

One m^3=

A

Volume of a cube whose edges are 1 m long

35
Q

The cm^3 is often used to

A

Express the volume of materials in a chem lab

36
Q

m^3=

A

1000000 cm^3

37
Q

When chemists measures volumes of liquids and gases they often use

A

A non SI unit called the liter

38
Q

Liter=

A

1 decimeter cubed

39
Q

1 liter =

A

1000 cm cubed

40
Q

1000 mL=

A

1 L

41
Q

mL and cm^3 are

A

Interchangeable

42
Q

Density

A

Ratio of mass to volume

Mass/volume

43
Q

SI unit for density is derived from

A

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

44
Q

Density is often expressed as

A

g/ cm^3 it g/mL

45
Q

Densities of gas are generally expressed as

A

kg/m^3 or g/L

46
Q

Density is a characteristic

A

Physical property of a substance

47
Q

Density doesn’t depend on the size of the same because

A

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

48
Q

Density can be used as

A

A property to help identify a substance

49
Q

Density varies with

A

Temperature

50
Q

Most objects expand as temperature increases thereby

A

Increasing in volume

51
Q

Density usually

A

Decreases with increasing temperature

52
Q

A conversion factor is a

A

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

53
Q

Each conversion factor equals 1 because the

A

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

54
Q

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

A

Without changing the validity of the equations

55
Q

Dimensional analysis

A

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

56
Q

Quantity sought =

A

Quantity given x conversion factor

57
Q

It is always best to begin with an idea

A

Of the units you will need in your final answer

58
Q

Conversion factors can be derived if you know the

A

Relationship between the unit you have and the unit you want

59
Q

1 m

A

10 decimeters