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CEM 141 MSU EXAM 1 QUESTIONS AND ANSWERS WITH SOLUTIONS 2024
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CEM 141 MSU EXAM 1 QUESTIONS AND ANSWERS WITH SOLUTIONS 2024
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CEM 141 MSU EXAM 1 QUESTIONS ANDANSWERS WITH SOLUTIONS 2024
The statement "If I add cold milk to hot coffee the temperature will decrease," is a? - ANSWER Claim,
always include an explanation and reasoning to the claim.
Scientific Model - ANSWER Models are used to make testable predictions
How much is a picometer? - ANSWER 0.1 x 10^-12 meters
Atomic Force Microscopy/ Scanning Tunneling Microscopy - ANSWER Microscopes that now allows us to
view atoms.
Leaves are green in the summer because? - ANSWER A plant's leaves are green in the summer because
they contain chlorophyll. Chlorophyll is a natural pigment that absorbs all wavelengths in the visible
spectrum except green.
How many naturally occurring elements exist? - ANSWER 91
What was Dalton's Atomic theory? (1808) - ANSWER - Elements are composed of small particles called
Atoms.
- Atoms of a given element are different from atoms of other elements.
-Chemical reactions happen when atoms are rearranged.
- Compounds contain 2 or more elements.
What was J.J. Thomson's experiment, and what did he discover? - ANSWER Using a Cathode Ray Tube,
he noticed that particles emerged to the cathode disk, and moved to another, the anode. These particles
could be deflected by electrical fields that would indicate that they would be negatively charged. They
were also deflected by magnetic fields, which showed the particles carried the charge as the ray was
bent. The most important observation was that the type of cathode used did not matter, as these
particles were still emitted. Therefore, Thomson deduced that the particles were universal and were in
fact negatively charged components of the atom. (The Electron)
, - ANSWER
What was Ernest Rutherford's experiment, what did he discover? - ANSWER Ernest Rutherford fired
Alpha particles (Hydrogen atoms) at a thin sheet of gold foil. Had Thomson's theory been right about the
plum pudding model, then the atoms should have all passed right through the sheet with no exceptions.
However, a small ratio of these particles were deflected. With this information, Rutherford figured there
was a small dense nucleus in the atom and that most of the atom was empty space.
What is the difference between Law and Theory? - ANSWER A law describes - tells you what happens
A theory explains - tells you why it happens
How big is an atom (H)? - ANSWER About 0.1 nanometer (0.1 x 10-9m)
Which is biggest? Atom, Molecule, Cell, or it depends? - ANSWER
Where did the idea of atoms come from? - ANSWER The Greeks
Atoms - ANSWER The smallest unit of an element
What is the evidence from Thomson's experiment that all atoms contain electrons? - ANSWER The
particles are identical regardless of the identity of the cathode(where they were emitted from).
What is an alpha particle? - ANSWER Has 2 protons and 2 neutrons. It is the nucleus of a Helium atom.
Coulomb's Law - ANSWER Negative and positive charges attract and like charges repel.
4 Types of Forces - ANSWER Gravitational, Electromagnetic, Strong Nuclear, Weak Nuclear
Gravitational Force - ANSWER Responsible for attraction between objects that have mass.
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