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55 Cards in this Set
- Front
- Back
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Approximately how many elements are known today?
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110
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Which element has the lightest atoms?
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Hydrogen
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Hoq does the age of most stars compare with the age of the solar system?
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Everything bigger than helium came from other stars. Atoms are recycled, older than us ourselves by millions of years.
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What is meant by the statement that you don't "own" the atoms that make up your body?
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Constantly being recycled
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How does the approximate number of atoms in the air in your lungs compare with the number of breaths of air in the atmosphere of the whole world?
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takes 6 years to diffuse into the atmosphere evenly
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How do the sizes of atoms compare with the wavelengths of visisble light?
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Smaller
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What causes dust to move with Brownian motion?
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air particles
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How is it possible to see individual atoms?
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You can use an electron microscope, which has wavelength of a thousand times smaller than light.
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DIstinguish between an atom and a molecule.
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Atom- smallest particle of an element that can be identified with that element. (Protons, Neutrons, Electrons, nucleous)
Molecule- bunch of atoms |
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How man elements compose pure water?
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hydrogen & oxygen
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How many individual atoms are there in a water molecule.
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three, H2O
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Cite an example of a substance that is made of molecules.
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CO2
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Cite a substance that is not made of molecules.
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Iron, Fa
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We smell things because certain molecules are attracted to our noses.
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false
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What is a compound?
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Substance that is made of atoms of different elements combined in a fixed proportion.
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Cite the chemical formulas for at least three compounds.
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C02, H20, N2
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What did Rutherford discover when his group bombarded a thin foil of gold with subatomic particles?
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Nucleus of an atom
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How does the mass of an atomic nucleus compare with the mass of the whole atom?
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Mostly concentrald at the center, atoms are mostly empty space
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What are the two kinds of nucleons?
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Protons and neutrons
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What is an isotope?
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Atoms of the same element having different numbers of neutrons
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Give two examples of an isotope.
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Deutrium, tritium
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How does the atomic number of an element compare with the number of protons in its nucleus? With the number od electrons that normally surround the nucleus?
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The atomic number of an element is based on how many protons it has, and there are the same amount of protons as there are neutrons.
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How does the mass of an electron compare with the mass of a nucleon?
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nucleons are 1800times as amassive as the electron
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What is an ion?
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Atom/molecule with a net electric charde, which is due to loss/gain of electrons
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Give two examples.
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HCL, NaCl
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At the atomic level, a solid block of iron is mostly empty space, explain.
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Iron blocks at atomic level are mostly empty space, because all atoms are mostly shells around a nuclues.
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What is the periodic table of the elements?
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Chart that lists atoms by their atomic number and by their electron arrangements.
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According to the shell model of the atom, how many electron shells are there in the hydrogen atom? Lithium? Aluminum?
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Hydrogen- 1
Lithium- 3 Aluminum-13 |
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What are the four phases of matter?
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Plasma, gases, liquids, and solids
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How does the arrangemet of atoms differ in a crystalline and noncrystalline substance?
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Crystalline- certain geometric structure to it
Noncrystalline- molecules, clumped together |
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What evidence do we have for the microscopic crystal nautre of some solids?
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Electron microscope & x-rays
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What evidence do we have for the visible crystal nature of some solids?
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Quartz, mica, gallena
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What happens to the density of a uniform piece of wood when we cut it in half?
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Nothing
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Uranium is the heaviest atom found in nature. Why isn't uranium metal the most dense metal?
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Density is based on the ratio of mass to volume, it may have the greatest mass, but it doesn't have thre greatest ratio.
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Which has the greater density- a heavy bar of gold or a gold ring?
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Same
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Does the mass of a loaf of bread change when you squeeze it? Volume? Density?
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No. Yes(decrease). Yes(increase).
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What is the difference between mass density and weight density?
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Mass density- g/cm^3
Weight density- N/cm^3 |
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What is the evidence for the claim that steel is elastic?
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Springs, returns to original shape if not reaching elastic limit
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That putty is inelastic?
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It will not return to it's original shape after having a force applied to it
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What is Hooke's law?
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The amount of compression/stretch, x is directly proportional to F.
2 x F = 2 x Stretch. F~X |
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What is an elastic limit?
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The point were an object can no longer retaliate to its original formation.
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A 2kg mass stretches 3cm. How far does the spring stretch when it supports 6kg?
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9cm
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Why is the cross section of a metal beam I-shaped and not rectangular?
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There is no stress in the center, so most of it's mass can be removed.
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Is a steel beam slightly shorter when it stands vertically?
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Yes.
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Where is the neutral layer is a horizontal beam supporting a load.
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Center
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If the linear dimensions of an object are doubled, how much does the total object increase?
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As the size of an object increases it grows heavier much faster than it grows stronger.
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How much does the volume increase if the linear dimensions are doubled?
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Four times as much
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As the volume of an object increases, its surface area also increases, but the ratio of surface area to volume decreases.
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True
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Which will cool a drink faster, an ice cube, or crushed ice?
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Crushed ice
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Which has more skin- an elephant or a mouse?
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Elephant
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Which has more skin per body weight- an elephant or a mouse?
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mouse
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If you have a square 2cm on each side, what is its area?
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4cm^2
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What happens if you X the side of a square?
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You x^2 the area
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Which has more area, a circle or a square?
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circle
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What would happen to the volume of a cube if it had been expanded three times?(1cm^2)
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It would increase by eight times.
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