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Chem unit 1 (ch 1-5)
Question | Answer |
---|---|
What is chemistry? | The study of matter and the transformation it undergoes. |
Chemical | If it has matter and takes up space. |
What is diatomic molecules? | Always stuck together. (Ex- O2) |
Molecular level | The behavior of matter |
Example of a checmical formula | H2O |
Example of a structural formula | O / \ H H |
What’s the scientific method? | Method of learning that emphasizes observation and experimentation to understand the world. A continuous creative process by which people learn about the physical universe. |
What does scientific method provide? | Fundamental foundation for the methods of science. |
Steps of the scientific method. | 1) observations 2) hypothesis- an educated guess that can be tested 3) experiment 4) model (theory) 5) further experiment |
What is a scientific law? | A brief statement that synthesizes past observations and predicts future ones. |
What is a theory ? | A unifying principal that explains what we observe in terms of underlying causes. |
Natural law | Tells you what |
Theory | Tells you why |
What is 200 years old with experimental evidence to support it including images of atoms? | Atomic theory |
What are the 2 main types of mathematical problems? | 1) unit conversion 2) word problems |
Common language | The order to communicate across out world we use this for units and equations. |
Scientific notation | Way of writing large and small numbers. |
Large #s | Whenever you move your decimal left you multiple by 10 |
Small #s | Whenever you move your decimal over to the right you divide by 10 |
Measured values | Have an uncertainty. For scientific numbers that are measured every digit is certain except the last, which is estimated. |
Precision | How closed are the dada points to one another |
Accuracy | How close the measurements to the true value |
Exact numbers | Do not have any uncertainty with them |
Measurements | Length (meter in metric) Mass (grams in metric) Volume (liters in metric) |
Values that are measured (uncertain at end) 1) all non-zero digits are significant 2) leading zeros aren’t significant 3) if zero is sandwiched between numbers it’s significant 4) end zeros with no decimals are not significant. | Significant figures |
Multiplication or division | Answer will have the same as the fewest of significant figures in calculation. |
Addition or subtraction | Same number of decimal places as the FEWEST of decimal places. Round down if 4 or less. Round up if 5 or more. (Last digit) |
Negative exponent | Same as writing unit in denominator. |