What is the Scientific Method?
A process used by scientists to explain observations in nature
True or False: The Scientific Method is repeated and checked by others
True
Does order matter in the Scientific Method?
Yes!
The Scientific Method is composed of what four steps?
Making observations, writing a hypothesis, doing experiments, and proposing a theory.
What are observations?
Facts obtained by observing and measuring events in nature
Are measurements considered observations?
Yes!
What is a hypothesis
A tentative explanation for an observation or scientific problem that can be tested by further investigation
A statement that explains observations is called what?
A hypothesis
Can an observation have multiple hypotheses?
Yes
What are experiments?
They are procedures that test hypotheses, scientific laws, or theories
Experiments have what effect on the hypotheses?
They confirm or disprove them
What is it called when an experiment is confirmaitory?
A theory or conclusion
What is a theory
A model that describes how the observations occur using experimental results
A theory is a proposed explanation for what?
Observations and Scientific Laws
Theories are general conclusions based on what?
Well established hypotheses
What explains why something happens?
Theories
Do theories have exceptions and expirations?
Yes!
What is the theory triple E?
Explanation, exception, and expiration
What is a qualitative observation?
It's a visual or observable observation
What is a quantitative observation?
An observation using numbers or measurement
What is a scientific law?
A statement that summarizes past observation and predicts future ones
Are scientific laws formulated from a series of related or unrelated observations?
Related
What predicts what will happen?
Scientific Laws
Do laws have expirations or exceptions?
No
Prediction/No exception/No expiration =???
Law
Explanation/Exceptions/Expirations =??
Theory
What is the formula for scientific notation?
A * 10^n
What does the A equal in the formula for scientific notation?
The decimal between 1 and 10
What does n equal in the scientific notation formula?
A whole number, positive or negative
Is 19.8 * 10^2 written in scientific notation?
No, because the decimal must be between 1 and 10
Is 9.18 * 10^-3.1 written in scientific notation?
No, because the exponent is not a whole number
How do you convert a number to scientific notation?
Move the decimal point to make it between one and 10. The number of the exponent is equal to the number of times you move the decimal over (positive to the left, negative to the
What are exact numbers?
Numbers that you can count
Examples of exact numbers
1 shoe, 18 tank tops
If you use tools, is a number an exact number?
No
What are measured numbers?
Numbers with a measurement attached
Examples of measured numbers
1.95 cm, 76 degrees fahrenheit
Measured numbers are comprised of what two components?
Number + Unit
Do measured numbers use tools?
Yes!
What is a certain digit?
A digit you can quantify
What is an estimated digit?
A digit you can't quantify
Which digit in a number is the estimated digit?
The last digit
What are significant figures?
All digits in a measured number including one estimated digit
Are nonzero digits always significant?
Yes
How many significant figures does 65.2 g have?
3
Is a zero between nonzero digits a significant figure?
Yes
How many significant figures does 29.05 grams have?
4
How many significant figures does 1.0087 mL have?
5
Are zeroes at the end of a number with a decimal place significant figures?
Yes
Are zeroes at the end of a number without a decimal place significant figures?
No
How many significant figures does 3.7500 cm have?
5
Do zeroes at the beginning of a number count as significant figures?
No
How many significant figures does 0.00245 mg have?
3
How many significant figures does 0.008 mL have?
1
How many significant figures does 2570 meters have?
3
How many significant figures does 1245500 have?
5
What is the significant figure rule for multiplication and division?
The answer has the same number of sig figs as the original number with the fewest sig
What is the rule for significant figures for Addition and Subtraction?
The answer has the same number of decimal places as the original number with the fewest decimal places
What are the three steps for significant figures in equations with both multiplication/division and addition/subtraction?
1. Follow Order of Operations
2. Keep Track of Significant Figures
3. Round at the End
Define Conversion Factors
The relationships between two units
What is dimensional analysis?
Using units as a guide to problem solving
What does dimensional analysis use to convert a quantity in one unit to a quantity in another unit?
Conversion factors
Units are treated like what?
Numbers
Formula for conversion factors
Original number * new unit/old unit
Convert 325 milligrams to grams
325 mg * 1 gram/1000 milligrams = 0.325 grams
What is density?
A physical property that relates the mass of a substance to its volume
What is the formula for density?
Density = mass(in grams)/volume(in mL or cc)
The minimum number of digits needed to express a measured number without a loss of accuracy is known as what?
Significant Figures
What are the four rules for significant figures?
1. Nonzero digits always count
2. Leading zeroes never count
3. Zeroes between non-zeroes always count
4. Trailing zeroes only count if in a decimal place
Is density a physical or chemical property?
Physical
What is the density of water?
1 gram/ml
What is the formula for mass?
Mass = Density x Volume
What is the formula for Volume
Volume = Mass/Density
What is a measuring tool used for?
Determining a quantity such as the length or the mass of an object
Formula for Volume of a Rectangle
a x b x c
Formula for Volume of a Cube
V = a^3
If the density of an object is larger than water, will it sink or float?
Sink
If the density of an object is smaller than water, will it sink or float?
Float
If the density of an object is roughly the same as water, will it sink or float?
Sink
What is chemistry?
The science of the everyday experience
What is the study of everything we touch, see, smell, or taste?
Chemistry
The study of matter and its composition, properties, and transformations is called what?
Chemistry
What are the three states of matter?
Solid, Liquid, Gas
What state of matter has a definite shape and volume?
Solid
What state of matter has no fixed shape but a definite volume?
Liquid
What state of matter has no fixed shape and an indefinite volume?
Gas
Can a solid be independent of its container?
Yes
Does a liquid take the shape of its container?
Yes!
How are the particles of a solid arranged
In a three dimensional array
How are particles arranged in liquid?
The particles are close together but can randomly move around and slide past one another
How are particles arranged in gas?
Particles are far apart and move around randomly
What is matter?
The material that makes up all things
Anything that has mass and occupies space (has volume) is called what?
Matter
Matter is composed of what?
Atoms and molecules
What makes up all matter?
Atoms
What is it called when atoms are joined together in units?
Molecules
What is a pure substance?
A substance composed of only one type of atom or molecule
A type of matter with a fixed or definite composition is called what?
A pure substance
What are elements?
They are pure substances that contain only one type of material
How many elements are on the Periodic Table?
118
What is a compound?
A substance composed of two or more elements combined in the same proportion
What do compounds consist of?
Two or more elements in a definite ratio
What is a mixture?
A substance composed of different pure substances that are not chemically united, but simply mixed together
What is homogeneous matter?
A substance that is uniform in appearance and has the same properties throughout
For a mixture to be homogeneous, what two characteristics must the sample have?
Uniform composition throughout the sample, Different parts of mixture are not visible
What does heterogeneous matter consist of?
Two or more physically distinct phases
What kind of substance will have different composition depending on where the sample is taken?
A heterogeneous mixture
All components are visible in what kind of mixture?
Heterogeneous
What is a phase? (Think mixtures)
A homogeneous part of a system separated from other parts by a physical boundary
What is an atom?
The smallest piece of an element
What is a molecule?
The smallest piece of a compound
Molecules are made from what?
Atoms
Are all molecules in a compound identical?
Yes!
Each molecule has the same number and type of what?
Atoms
A combination of pure substances is called what?
A mixture
The components of a mixture do not lose their identities and may be separated by what physical means?
Boiling, filtration, and magnetism
If two substances have different boiling points they may be separated via what process?
Distillation
Boiling point of ethanol
78 degrees Celsius
Boiling point of water
100 degrees celsius
What converts gas to liquid?
Condensation through cooling
If two substances have different states of matter they may be separated via what process?
filtration