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55 Cards in this Set

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