Chem Analyzing Data

A quantity that has both a number and a unit

What is a measurement?

An international system (SI) of measurement used in science

What is the Metric System?

Seven units

How many units are in the SI System?

Base units

What are the SI System units called?

Metric prefixes

What can you add to base units?

Makes it more convenient, makes it larger/smaller than the base unit

What does a metric prefix do to the base unit?

mL (mililliters), in graduated cylinder

What unit do you use for volume?

g (grams), on balance

What unit do you use for mass?

C (Celsius), in thermometer

What unit do you use for temperature?

The measure of the average kinetic energy of the particles in an object

What is temperature?

m^3

Volume equation in meters

m/s

Velocity equation in meters

Measure volume at bottom of curve (meniscus)

How would you measure the volume of a liquid in a graduated cylinder?

Energy in motion, the faster the atoms are moving, the higher the temperature

What is kinetic energy?

Kelvin scale

What is the SI unit for temperature?

Kelvin = Celsius + 273

Kelvin scale equation

Water freezes at 0 and boils at 100

Celsius Scale

Celsius = Kelvin - 273

Celsius scale equation

Celsius will be used most in chemistry, Fahrenheit is not generally used in science-- hard to remember

Which measure of temperature is used most in science? Which is used least?

Combinations of base units, derived units

Other SI units can be made from ________________, called ______________

A physical property of matter defined as the amount of mass per unit volume

What is density?

density = mass/volume

Density equation

g/cm^3 for solids, g/mL for liquids and gases

What are the common units of density?

By writing all numbers known for certain and by estimating a final digit

How do you make a measurement?

Must be estimated, uncertain

A digit that ______________ is called an _____________

The certain digits and the estimated digit of a measurement together

What is a significant digit/figure

All non-zero numbers are significant

What is the first rule for significant figures?

Leading zeroes are never significant

What is the second rule for significant figures?

Zeroes between nonzero numbers are significant

What is the third rule for significant figures?

Trailing zeroes are significant only if the number contains a decimal point

What is the fourth rule for significant figures?

No, so we need to make sure our answer does not have more sigfigs than the original numbers

Do calculators know what significant figures are?

The number with the fewest sigfigs determines the number of sigfigs in the answer

What are the rules for multiplying/dividing sigfigs?

The number with the farthest left sigfig determines the number of sigfigs in the answer, exact numbers do not limit the number of sigfigs in the answer

What are the rules for adding/subtracting sigfigs?

Accuracy and precision

What are the two kinds of reliability in measurement?

How close a measurement is to the accepted value or standard

What is accuracy?

How close a series of measurements are to each other

What is precision?

A comparison of a measurement to its accepted value, indicates accuracy of a measurement

What is percent error?

% error = (|measured - accepted|/ accepted) x 100

Percent error equation

Measured = your value, accepted = actual value

What do the measured and accepted values mean?

A method of representing very large or small numbers using powers of 10

What is scientific notation?

M x 10^n

Scientific notation equation

M is a number between 1 and 9.9, n is an integer, represents how many times you moved the decimal

Explain scientific notation equation

Move decimal until there's 1 digit to its left, places moved = exponent-- exponent is positive when moved left, exponent is negative when moved right

How do you convert a number into scientific notation?

Significant figures

Only include... (scientific notation)

If the exponents are the same, add/subtract numbers in front and bring down exponent; if exponents are different, move a decimal to make them the same, then add/subtract

What are the rules for adding/subtracting scientific notation?

Multiply/divide the M values; multiplication: add exponents, division: subtract exponents

What are the rules for multiplying/dividing scientific notation?

A systematic approach to problem solving that uses conversion factors to move, or convert form one unit to another

What is dimensional analysis?

A ratio of equivalent values having different units

What is a conversion factor?

It must cancel one unit and introduce a new one; all units except desired unit must cancel

What are the two things a conversion factor used in dimensional analysis must accomplish?

A visual display of data that makes trends easier to see than in a table

What is graphing?

Circle/pie graph, bar graph, line graph

What are different types of graphs?

Aka pie chart, has wedges that visually represent percentages of a fixed whole

What is a circle/pie graph?

Often used to show how a quantity varies across categories

What is a bar graph?

Independent variables are plotted on x-axis and dependent variables are plotted on y-axis

What is a line graph?

Label the axis, use quantities and also proper units

What is the first step to creating a graph?

Choose a range that includes all the results of the data

What is the second step to creating a graph?

Calibrate the axis

What is the third step to creating a graph?

Give the graph a title

What is the fourth step to creating a graph?

Use a smooth line to connect points

What is the fifth step to creating a graph?

Directly proportional and inversely proportional

What are the two different kind of proportional relationships between variables?

As one variable increases, other decreases; as one variable decreases, other increases; hyperbola on graph

What does it mean when two variables are inversely proportional?

As one variable increases, other also increases; as one variable decreases, other also decreases; straight line on graph

What does it mean when two variables are directly proportional?