Unit 1A

If 1 is on the top

Divide

the last digit of every "good" scientific measurement is

Estimated

Exact counting of discrete objects ex:

Ex. 12 eggs in a carton

have an unlimited number of sig figs

Exact number

Accuracy—-> % error formula

Experimental mean- accepted/ accepted x 100

The least accurate and precise measurement in addition and subtraction is the one reported to the

Highest place value. Ex: 2.609, 301.2, 0.1205, 303.9295. 301.2 is the least accurate and precise

Conversion Factor Formula

Information given x conversion factor(s)=information sought

The calculated answer is written to the same place value as the

Least accurate and precise measurement. (Highest place value)

If one is on the bottom

Multiply

Isotopes of the same element are the same in color odor etc but different in

Neutrons/mass

Reliability of a process/measuring device improves as

Percent error goes down, therefore accuracy improves

Determine using mean and percent difference or standard deviation

Precision

Mass is

Protons+neutrons

Charge is

Protons-electrons

Can be best used to express significant figures

Scientific notation

preserve the accuracy and precision of measurements and calculations

Sig figs

"Leading zeroes" only hold place value and are not

Significant

If one or more zeroes are between non zeroes, they are

Significant

One or more trailing zeroes if there is a decimal point present is

Significant

The reliability of a measurement is based on

Skill of the measurer and the level of accuracy of the measuring device

An error that tends toward being either too high or too low

Systematic error

Are either significant or place holders

Zeroes

conversion factor

a ratio of equivalent measurements

Integral numbers ex:

1 mile=1.609km

1 lb

453.6 g

2300.0 has how many sig figs

5

The estimated value is typically

+\- 1

Electrons have a mass of

0

Protons and neutrons have a mass of

1 amu

Conversion factor example

1 foot/12 in or 12in/1 foot

2.54 cm=

1 in

kilo

1000

Defined quantities ex:

1km=1000m

0.0025 (how many sig figs? why?)

2

2300 has how many sig figs?

2

1 ton = ____ pounds

2,000 pounds

1kg=?lb

2.2lb

2300 in scientific notation

2.3 x 10^3

0.0025 in scientific notation

2.5 x 10^-3

0.2500 in scientific notation

2.500x10^-1

203 has how many sig figs

3

0.2500 how many sig figs

4

1.005 has how many sig figs

4

2.345 has how many sig figs

4

Every reported non-zero is

A sig fig

True mass=

Accepted value

Determine using mean and percent error

Accuracy

Any percent error greater than 5 is not

Accurate

Atomic mass is at the

Bottom of the element

"Good" scientific measurements are reported so that every digit is

Certain

Ions never act the same if

Charge is changed

The greater the number of sig figs the greater

The certainty of the measurement

The least accurate and precise measurement in multiplication and division is the one with

The least # of sig figs

how close measurements are to the actual value

accuracy

0.01

centi

using units as a guide to solving problems is called

dimensional analysis

Order of discovery of subatomic particles

electron, proton, neutron

centi

hundred

0.001

milli

Which subatomic particle is biggest

neutron

Protons and neutrons are found in the

nucleus of an atom

Electrons are found

outside the nucleus

how close a set of measurements are to each other

precision

an error that has the equal probability of being too high or too low

random error

Reliability of a process/measuring devices improves as Standard deviation goes down,

therefore precision improves

milli

thousandth