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Chemistry is the study of... |
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Matter & the transformation of matter |
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Applied research: |
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Developing basic research; determining the lightest and strongest metal to be used for an airplane wing. |
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50mL small BBs + 50 mL large BBs = 90 mL of BBs |
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Many of the smaller BBs are able to fit within the pockets of space that were empty within the 50 mL of large BBs |
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Scientific hypothesis is: |
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Testable assumption used to explain an observation |
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Which of the following represents the largest quantity of mass?
a. 100 kg
b. 100,000,000,000 micrograms
c.100,000,000 milligrams
d. 100,000 g
e. All the masses are the same
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All the masses are the same |
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Which has stronger attractions among its submicroscopic particles: a solid at 25 C or a gas at 25 C? |
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The attractions among the submicroscopic particles of the solid must be stronger than the attractions among the particles of the gas. |
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Which of the following statements best describes an element? |
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A material consisting of only one type of atom |
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Which of the following would be considered a physical property? |
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density |
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How many atoms of O are in H3OClO4? |
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5 atoms |
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If you filter sea water to remove all of the particles you would be left with a clear... |
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homogeneous mixture called a solution |
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Which of the following statements from Dalton's atomic theory would best describe the following observation: |
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Atoms can be neither created nor destroyed in a chemical reaction. |
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Which of the following statements best summarizes the Law of Definite Proportions? |
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The mass ratio of the elements in a compound will be the same regardless of how the compound was made. |
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The following statement describes which subatomic particle best? It has a relatively large mass |
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A proton and neutron (P&N) |
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If the particles of a cathode ray had a greater electric charge, the ray passing through a magnetic field would bend: |
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more because of a greater electromagnetic attraction |
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What does the following element description 186O? |
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an oxygen atom with 6 protons and 12 neutrons |
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If a material has a half-life of 24 hours, how long do you have to wait until the amount of radioisotope is 1/8 its original amount? |
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96 hours |
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A rem is: |
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A unit for measuring radiation exposure |
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Which of the following statements best describes the strong nuclear force? |
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The force is very strong but has a very short range. (Strong short little man) |
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Which of the following nuclear equations correctly describes alpha emission? |
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U ...Th + He (Uthhe) |
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Which of the following is a major disadvantage of nuclear-fission-based power plants? |
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The byproducts of the fission process are radioactive and have very long half-lives & The power plants are complex and there are many safety requirements to prevent contamination of the environment. (BYPRODUCTS RADIOACTIVE HALF-LIVES,COMPLEX SAFETY REQUIREMENTS) |
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When food is irradiated with gamma rays from a cobalt-60 source, does the food become radioactive? Why? |
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No. The gamma rays do not have sufficient energy to initiate the nuclear reaction in the atoms of the food. |
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An example of basic research is: |
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The study of the composition of the atom. |
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Not considered matter? |
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LIGHT! |
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When water freezes it expands. What does this say about the density of ice compared with the density of water?
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Ice is LESS DENSE than water because it has MORE VOLUME for the same mass. |
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The boiling point of methanol is 65 C and the boiling point of ethanol is 78 C. Which of the following statements is true? |
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At 70 C you would have methanol gas and liquid ethanol. |
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How many atoms are in one molecule of Na2SO4? |
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7 |
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Which atom is largest? |
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Rb |
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Which of the following elements are in the same period as Mg?
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Cl (Periods go across) |
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Elements that are in the same ______ have a tendency to have very similar chemical properties due to periodic trends. |
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GROUP! |
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Classify the following as element, compound, or mixture: table salt, stainless steel, table sugar, aluminum ice. |
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Compound; Mixture; Compound ; Element; Compound
CMCEC |
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Which of the following is NOT a property of an electron? |
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charge CHANGES depending on MASS |
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Which of the following statements from Dalton's atomic theory would best describe the following observation:
The mass of all of the products is equal to the mass of all the reactants in a given reaction.
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Atoms can be neither created nor destroyed in a chemical reaction. |
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You heat 20 g of a metal in an open container and after the experiment you are left with 35 g of a powdery substance. Which statement best explains what happened? |
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The metal reacted with some air or something else we did not originally measure. |
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What does the following Element 238 92 U mean? |
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Uranium atom with 146 NEUTRONS and 92 PROTONS. |
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Why are the atomic masses listed in the periodic table not whole numbers? |
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The atomic masses are average atomic masses of various elemental isotopes |
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If an element has 18 protons and 20 neutrons and 18 electrons, which expression correctly identifies the element? |
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Argon-38 (18,20,18) |
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If a material has a half-life of 24 hours, how long do you have to wait until the amount of radioisotope is 1/4 its original amount? |
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48 hours |
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Why wouldn't you use carbon-14 dating on a piece of shell that was estimated to be 1 million years old? |
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The amount of radioactive carbon in the sample would probably be too small to measure. |
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What is the main technical difficulty in dealing with fusion reactions? |
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The amount of energy needed to overcome the electrical repulsion of the reactants is extremely high |
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How is it possible for an element ot decay "forward in the periodic table"-- that is, to decay to an element of higher atomic number? |
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As a beta particle is released, a neutron transforms into a proton (DECAY HIGHER=TRANSFORMER PROTON) |
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