化學
化學反應、化學計量、分子結構與元素性質。
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a chemical engineer must report the average volume of a certain polluta…
$8.98$ L
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a chemical engineer must report the average volume of a certain polluta…
19.15 L
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a chemistry student must write down in her lab notebook the concentrati…
$0.2964\ g/mL$
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how do human activities impact biogeochemical cycles? a. they have no e…
1. b. They can disrupt these cycles, leading to environmental consequences 2. b. Climate change effects 3. d. Carbon
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a student fills a beaker with distilled water and marks the volume as 9…
44.9 mL
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1) please provide iupac (systematic) names for the following: a. b. c.
a. 2,5 - dimethylheptane b. 1 - chloro - 1 - methylcyclohexane c. 1,3 - dimethylcyclopentane
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1) please provide iupac (systematic) names for the following: a. b. c.
a. 3,5 - dimethylheptane b. 1 - chloro - 1 - methylcyclohexane c. 1,3 - dimethylcyclopentane
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you place a pot of water on the stove to boil noodles for dinner. as th…
B. Endothermic
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the particle theory of matter suggests... o molecules of solids, liquid…
molecules of solids, liquids and gases are in constant motion
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all matter is made up of small particles called.... electrons salts ele…
D. atoms
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temperature measures the speed of the molecules in matter. thermometers…
44, 42, 84, 64, 18
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a student made this object in order to represent a chemical compound. w…
model
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read the lines from act ii, scene ii of romeo and juliet juliet o romeo…
hopefulness and longing
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write a problem question for this descriptive investigation. how can th…
First, use a magnet to remove iron filings. Then, filter the mixture to separate sand and gravel from the salt - water solution. Evaporate the water from the salt - water solution…
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which pieces of equipment would be used to measure the density of a sol…
C. a graduated cylinder and a balance
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doreen schmidt is a chemist. she needs to prepare 28 ounces of a 11% hy…
The amount of 14% acid solution is 16 ounces. The amount of 7% acid solution is 12 ounces.
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which of these will best separate a saltwater solution? using a paper f…
allowing the water to evaporate
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in this investigation, you will make a mixture, describe the individual…
How can the mixture of sand, gravel, iron filings, salt, and water be separated into its individual components?
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6 multiple choice 1 point according to table 1, as the nacl concentrati…
6. decreases 7. 0.25 mg 8. Yes, because in Experiment 1, there will be rust caused by exposure to water.
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1. grind salt into a powder. 2. heat a small beaker of water. 3. comple…
4
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4. a rock that contains a metal or other economically useful mineral is…
4. C. ore 5. B. chemical and salt
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5 multiple choice 1 point given the information provided by reactions c…
becomes more basic because more hydrogen ions are gradually consumed than are hydroxide ions.
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how does the authors use of free verse allow him to effectively express…
The use of free verse allows him to use unconventional rhythm.
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3 multiple choice 1 point which of the following correctly lists the co…
3. Diethyl Ether, Water, Anisole, Diphenyl Ether 4. The relative distance between the molecules due to branching in the compound
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multiple choice 1 point the impact of adding acetic acid and bleach to …
increasing rust regardless of an electric current.
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types of reactions quick check in a chemical reaction, substance a tran…
A. Substance B is reduced and acts as the oxidizing agent.
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question 12 mark this question the three types of resources available i…
B. physical, digital, and human
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why was galileo put under house arrest by the catholic church? galileo …
Galileo was put under house arrest for his discoveries and theories that went against Catholic teachings.
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types of reactions quick check which statement correctly describes the …
Not all reactions fit into one category, and some reactions can fit into more than one category.
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in a synthesis reaction, two atoms of sodium (na) combine with one mole…
two
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types of reactions quick check in the decomposition of water, why is tw…
There are two atoms of hydrogen and one atom of oxygen in a water molecule.
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which component is transferred between substances in an oxygen - reduct…
electrons
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types of reactions quick check in a chemical reaction, substance a tran…
Substance B is reduced and acts as the oxidizing agent.
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multiple - choice question true or false: all chemical changes are acco…
True
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any time you burn something, it changes the object. is this a chemical …
Chemical change
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if you leave metal out in the rain, and it rusts, is that a physical ch…
Chemical change
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if you ferment a material like sugar or corn and it changes into someth…
Chemical change
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what does the document suggest about the mass of atoms? it is always ch…
It is not visible.
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according to the document, what might have modeled atoms in the 1800s? …
Invisible balls
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why was the gold foil used in the experiment instead of another metal? …
It is more malleable
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true or false: all changes in the state of matter are chemical changes.…
False
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which of these are illegal activities? check all that apply. running a …
Running a pyramid scheme, Threatening to harm property, Downloading a virus, Hacking a computer
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if you melt ice down to water, is that a physical change or a chemical …
Physical change
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what does the document imply about the colors of atoms? atoms change co…
Atoms are colorless.
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if you take a metal and change it so that it is a thin wire, is that a …
Physical change
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if atoms are neutral, what can be inferred about the number of protons …
The number of protons equals the number of electrons.
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if you fold an object, is that a physical change or a chemical change? …
Physical change
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if you grind something up, is that a physical or chemical change? chemi…
Physical change
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10. a mixture of helium and neon gases has a total pressure of 1.2 atm.…
$0.4$ atm
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2. summarize: compare all the acidic substances and all the alkaline su…
Metal oxides (when dissolved in water), metal hydroxides, some salts
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multiple - choice question melting point is a chemical property. physic…
physical property.
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2. summarize: compare all the acidic substances and all the alkaline su…
Non - metal oxides (when dissolved in water), organic acids, and inorganic acids tend to be acidic.
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multiple - choice question condensation point is a physical property. c…
A. physical property
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multiple - choice question viscosity is a chemical property. physical p…
physical property.
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3 what is the significance of the atomic number? a) it represents the n…
C. It indicates the number of protons in the nucleus.
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multiple - choice question being combustible is a physical property che…
chemical property
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multiple - choice question freezing point, like water becoming ice, is …
physical property.
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1 test: use the gizmo to find the ph of each of the available substance…
| Material in the tube | pH value | Acidic, alkaline, or neutral? | | ---- | ---- | ---- | | Baking soda | 9 | Alkaline | | Bleach | 12 | Alkaline | | Coffee | 5 | Acidic | | Cola…
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flammability tells you if a chemical rusts - or reacts with oxygen. how…
how a chemical reacts to an open flame.
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gizmo warm - up the strength of an acid or base is measured on the ph s…
11, alkaline
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20. the most common method of producing electricity is ___. a. chemical…
c. magnetism
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gizmo warm - up the strength of an acid or base is measured on the ph s…
Blue
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what is a physical property? it describes how substances react with oth…
It describes a physical change in the appearance WITHOUT changing it into another substance.
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multiple - choice question what is viscosity? how thick, or thin, a liq…
how thick, or thin, a liquid is
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multiple - choice question malleable means breakable can be shaped can …
can be shaped
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5) choose the best answer. the three pieces of an atom are called ____.…
5) C. subatomic particles 6) A. positive 7) D. neutral
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4) choose the best answer. are the smallest parts of matter that still …
A. Atoms
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12. adding liquid or basting during the roasting process will add a. dr…
12. b 13. a 14. d 15. a 16. c 17. a 18. d 19. d 20. b 21. b 22. a, c 23. d
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16. valence electrons are contained in the ______ shell a. inner b. out…
B. outer
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6. a sample of liquid nh₃ is brought to its boiling point. will the hyd…
The hydrogen bonds will break, and the covalent bonds will not break.
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2) choose all that apply. which two facts are about electrons? they rep…
- They move extremely fast in the electron cloud around the atom's nucleus. - The negatively - charged particles are smaller than protons and neutrons.
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15. the valence shell of an atom is the ______ shell. a. inner b. outer…
B. outer
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lewis electron dot structures are shown for some of the elements in the…
1. Lithium reacts with oxygen to produce lithium oxide ($Li_2O$). 2. Beryllium reacts with oxygen to produce beryllium oxide ($BeO$).
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section 1 stars continued class color temperature (°c) elements detecte…
6. B 7. B
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10) choose all that apply. which four types of changes might occur duri…
temperature change, color change, production of gas, production of light
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10) choose all that apply. which four types of changes might occur duri…
production of light, production of gas, color change, temperature change
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9) choose all that apply. which two facts are about a chemical change? …
The change results in a new substance. The change cannot be reversed.
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a solution containing 2.8 moles of magnesium bromide is combined with a…
B. 2.1 M
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1) choose all that apply. which two facts are about physical changes? t…
The substance changes size or shape but remains the same substance. It is sometimes possible to change the substance back.
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electronegativity < 1.0 1.0 ≤ electronegativity < 2.0 2.0 ≤ electronega…
B. fluorine (F)
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type the correct answer in the box. given: cac₂ + n₂ → cacn₂ + c in thi…
70.5
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select the correct answer. which statement correctly relates two substa…
C. $NH_4^+$ is the conjugate acid of $NH_3$.
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31 select the correct answer. what is the molar mass of alcl3? a. 62.43…
D. 133.33 g/mol
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what is the empirical formula of a compound with 35.94% aluminum and 64…
D. $Al_2S_3$
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use the periodic table to determine what element cesium - 135 ($_{55}^{…
D. $^{135}_{56}\text{Ba}$
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a compound has a molecular weight of 112.124 atomic mass units and the …
E. $C_{6}H_{8}O_{2}$
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the compound diborane can be used as a rocket propellant. what is the p…
E. 78%
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select the correct answer. which sentence best explains the high meltin…
E. The negative side of each water molecule is attracted to the positive sides of nearby molecules.
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grammar: possessive nouns practice a possessive noun shows ownership. i…
1. Underlined: library’s; Singular 2. Underlined: children’s; Plural 3. Underlined: young adults’; Plural 4. Underlined: books’; Plural 5. Underlined: book’s; Singular 6. Underlin…
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select the correct answer. what is the effect of high activation energy…
D. It makes the reaction harder to start
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drag each label to the correct location. identify the molecular shape o…
trigonal pyramidal, tetrahedral, trigonal planar, bent
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select the correct answer. which characteristic is a property of water?…
D. strong cohesion
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drag each quantity to the correct location on the table. complete the t…
| | Bond Energy | Bond Length | |--|--|--| | N - N | 167 kJ/mol | 145 pm | | N = N | 418 kJ/mol | 125 pm | | N≡N | 942 kJ/mol | 110 pm |
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select the correct answer. among these properties of acids, bases, or b…
E. sour taste
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11 select the correct answer. identify the number of moles in 369 grams…
B. 4.98 moles
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type the correct answer in the box. sodium carbonate (na₂co₃) is someti…
109
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in a cars engine, the spark plug creates a flame to begin the combustio…
released
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select the correct answer. which action would reduce the activation ene…
A. adding a catalyst to the reaction
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how many atoms of n are in 137.0 grams of n₂o₃? a. 1.085×10²³ b. 1.802×…
D. $2.171\times 10^{24}$
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14. (2 points) explain why a high rate of heating during melting point …
A high rate of heating during melting point determination could result in a lower melting range than the actual because heat does not distribute evenly and the thermometer registe…