Chemistry Chapter 3

Precision

Is a quantitative evaluation of the exactness of measurement or a measuring instrument

Accuracy

Is a quantitative term that describes how close a measurement is to the actual or excepted value of the dimension measure

Measurement

Is act of comparing an unknown quantity to an Standard unit

Dimension

Is any measurable property of the physical universe. examples length, mass, volume, time and temperature

The kilogram

Is the only Si base unit that is still defined as a man made object

The SI

Is the standard metric system used by scientists worldwide

Significant digits apply only to measured data

SD rule 1

All zeros between nonzero digits are significant

SD rule 3

Decimal points define significant digits

SD rule 4

Significant digits in the ones place are followed by a decimal point

SD rule 5

The decimal factor of scientific notation contains only significant digits

SD rule 6

All nonzero digits are significant

SD rule2

True

Significant digits do not apply to counted or pure numbers true or false

True

Significant digits do not apply to ratios that are exactly 1 by definition true or false

True

Precision cannot say how correct a measurement is. true or false

Unit

A label used to specify a measurement dimension

Scale

A means of measuring that is subdivided into units of measurement

Number and a unit

A measurement consist of two parts a________ and a ______.

True

The uncertainty of the tenths digit is why the last digit is called the estimated, uncertain, or least significant digit. True or false

Joule

The unit of thermal energy is the

Two purposes of significant digits

they determine the important digits you need to record when making a measurement, and they indicate the precision of your measurement.

True

scientists recognize there is always some uncertainty involved with any measurement. True or False

Graduated

Accurately subdivided into measuring units

Digital instrument

An instrument that has a display consisting of only numerical digits is called

Analog

An instrument that measures by comparing the object being measured directly to a scale or display a reading using a pointer against the scale

Derived units

Any mathematical combination of the base units.

Metric Sysem

Any measuring system in which different sized units are related to each other by multiples of 10

Literal equation

Are those written so that most or all quantities are represented by letters than by numbers

Unit conversion

Consist of multiplying the measurement by a conversion factor

True

France became the first European nation to adopt a national metric measurement system consisting of the kilogram and the meter. True or False

True

If the percent error is small, then the measurement is considered to be accurate. True or false

Conversion

Is a fraction that contain both the original units and the equivalent value in the new unit

Unit

Means one of something

Systematic

Means the method is based on step by step procedures

True

Measurements do not have unlimited precision.true or false

True

Minimizing errors in measurement is an important part of experiment design. True r false

Compound calculations

Multiple operations are called

Immunotherapy

One very effective treatment for allergies is called

True

Only like units can be added or subtracted, but any unit can be multiplied or divided, when appropriate true or false

Read the statement of the problem Determine the method of solution Choose the specific tools to use Check and format

Steps in problem solving:

true

The SI contains 22 derived units True or False

In a conversion factor ratio, the new unit is in the numerator and the old unit is in the denominator.

The basic rule for using conversion factors is

True

The bridge method applies only to multiplication and division; it cannot be used for addition and subtraction. True or False

Kilogram

The platinum iridium alloy establishes a stable. Corrosion proof reference that is still the standard for the __________ today

True

Unit conversion does not change the amount of the quantity, just the number and units in which it is expressed.True or False

The kilogram

Was originally defines as the mass of one cubic decimeter of water

True

When the mass is given in grams, cubic centimeters are used as the unit for volume; when the mass is given in kilograms, cubic meters are used.true or false

Formula

are mathematical models of natural phenomena.

Bridge notation

is a special notation for multiplying and dividing several measurements together at the same time.

Significant digits

only those that are known for certain plus one estimated digit.

Percent error

quantity derived from a method that compares the magnitude of the measurement error with the size of the measurement.