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.