midterm review. chem.

Living things can exist on Earth because _, a chemical in Earth’s atmosphere, absorbs most of the radiation from sun before it reaches Earth’s surface
ozone
Ozone consists of _ particles of oxygen. (number)
three
Lowest layer of earth’s atmosphere?
troposphere
True or false. Clouds are found in the troposphere. So are airplanes and all of Earth’s weather.
true
Ozone is located in which layer of the atmosphere?
stratosphere.
About _% of Earth’s ozone is spread out in a layer that surrounds and protects our earth.
90
What is formed when oxygen gas is exposed to ultraviolet radiation in the upper regions of the stratosphere?
ozone
What is a chemical that consists of chlorine, fluorine, and carbon?
chlorofluorocarbon
True or false. CFC’s readily react with other chemicals.
false
What are cfc’s used for?
coolants in refrigerators, coolants in Ac’s, plastic foams, propellants in spray cans
What is the study of matter and the changes that it undergoes?
chemistry
What is anything that has mass and takes up space?
matter
what is a measurement that reflects the amount of matter
mass
True or false. Heat, light, radio waves, and magnetic fields are matter.
false
_ is a measure not only of the amount of matter but also of the effect of Earth’s gravitational pull on that matter.
weight
What does the word macroscopic mean?
matter that you do not need a microscope to see.
What is a systematic approach used in scientific study that is an organized process used by scientists to do research?
the scientific method
What are the steps to the scientific method?
Observation. Hypothesis. Experiment. Conclusion. Theory. scientific law.
_ data is information that describes color, odor, shape, or some other physical characteristic.
qualitive
_ data tells you how much, how little, how big, or how tall. It’s when scientists measure temperature, pressure, or volume.
quantitive
A _ is a tentative explanation for what has been observed. ; educated guess
hypothesis
True or false. A hypothesis means nothing unless there are data to support it.
true
An _ is a set of controlled observations that test the hypothesis.
experiment
Difference between independent and dependent variable?
independent is the one that you plan to change; dependent is when its value changes in response to a change in the independent variable.
What is a control in an experiment?
standard for comparison’ like a test tube out of three that all have different substances
A _ is a judgement based on the information obtained.
conclusion
True or false. A model cannot be tested nor used to make predictions.
false
A _ is an explanation that has been support by many, many experiments.; However they are still subject to new experimental data.
theory
_ research seeks to gain knowledge for the sake of knowledge itself.
pure
_ research is research undertaken to solve a specific problem.
applied
_ is the practical use of scientific information
technology
x

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