化學
化學反應、化學計量、分子結構與元素性質。
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short answer i: name the following compounds. 16. (nh₄)₂so₄ 17. sf₆ 18.…
16. Ammonium sulfate 17. Sulfur hexafluoride 18. Sodium hydroxide 19. Carbon dioxide 20. Iron (II) nitrate (or ferrous nitrate)
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aqueous copper (ii) nitrate reacts with aqueous sodium hydroxide to yie…
\(Cu(NO_3)_2(aq)+2NaOH(aq)\to Cu(OH)_2(s)+2NaNO_3(aq)\)
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type the numbers that will balance this equation. if no number is requi…
1, 1, 1, 2
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type the numbers that will balance this equation. if no number is requi…
4, 3, 2
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type the numbers that will balance this equation. if no number is requi…
1, 5, 3, 4
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laboratory entrance exa 帐号:姓名:考试时间:60分钟 二.多选题(共12题,共24分) 2.among the fo…
C. hydrofluoric acid
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二.多选题(共12题,共24分) 1.precautions for chemicals storage include that().(2分…
A. forklifts must be equipped with fire shields when they enter chemical warehouses, B. various chemicals must be stored in categories, C. waste chemical containers must be stored…
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5) type in the correct answers using the following bohr models. type th…
F: 7 Cl: 7 Br: 7
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1) choose the best answer. a(n)_____electron is an electron that occupi…
1. A. valence 2. B. orbitals
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14. choose all that apply. which five postulates were proposed by dalto…
- Atoms of one element can combine in whole - number ratios with atoms of other elements to form compounds (law of multiple proportions). - All matter is composed of extremely tin…
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3. choose the best answer. the rate of motion over a certain amount of …
- 3. speed - 4. Unbalanced
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13. choose the best answer. the center of an atom that contains protons…
nucleus
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11. choose the best answer. the positively charged subatomic particle i…
11. proton 12. neutron
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10. drag and drop the scientists with the statements. reasoned that it …
Democritus: reasoned that it is impossible for all matter to be made of classical elements. Leucippus: proposed that matter could only be divided until you reached the smallest pa…
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look at the model. then, choose the best answers. 8. choose the best an…
8. A positively charged core is surrounded by mostly empty space, and negatively charged electrons orbit the core. 9. Earnest Rutherford
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7. choose the best answer. the negatively charged subatomic particle is…
electron
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5. choose the best answer. who proposed this model? aristotle john dalt…
5. J. J. Thomson 6. Negative electrons float in a "soup" of positively charged material.
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4. choose the best answer. this law was proposed by antoine lavoisier a…
law of conservation of mass
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2. choose the best answer. which statement is true about this model and…
2. A. A positively charged core is surrounded by mostly empty space, and negatively charged electrons orbit the core. 3. Earnest Rutherford.
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1. choose the best answer. this law was proposed by joseph proust and i…
law of definite proportions
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12) label the picture of rutherfords model of an atom
1. B: b. electrons 2. A: a. nucleus
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11) drag and drop the terms with the definitions. subatomic particles t…
- subatomic particles that do not have an electric charge: neutrons - positively charged subatomic particles: protons - negatively charged subatomic particles: electrons - the cen…
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cathode rays must travel through a vacuum. 5) label the picture of thom…
1. A: a. Negatively charged electron 2. B: b. Positively charged material
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look at the following image. what feature from this model caused scient…
Negative electrons float in a "soup" of positively charged material.
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1. all of the following are true regarding cleaning and sanitizing in f…
1. Only surfaces that come into contact with RAW foods must be cleaned and sanitized. 2. True 3. True 4. Stacking cardboard boxes in storage for later use 5. Ingesting contaminate…
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7) choose all that apply. select the five postulates proposed by dalton…
- Atoms cannot be created or destroyed (law of conservation of mass) nor can they be divided into smaller particles. - All matter is composed of extremely tiny particles called at…
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6. choose the best answer. an object in motion, such as an automobile, …
6. kinetic 7. thermal energy
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6) drag and drop the descriptions with the laws. proposed by joseph pro…
- proposed by Joseph Proust and known as the law of constant composition: law of definite proportions - proposed by Antoine Lavoisier and commonly applied to chemical reactions: l…
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5) choose the correct scientific notation. what was a limitation of dal…
The model was much simpler than the real system of an atom.
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3) choose the best answer. which law is also one of daltons postulates?…
- 3) law of conservation of mass - 4) billiard ball model
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1) choose the best answer. which law did dalton propose? law of conserv…
1. law of multiple proportions 2. experiments with different gas pressures
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10) choose the best answer. what did early greek philosophers theorize …
Matter consists of classical elements and atoms.
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9) choose the best answer. look at the following model. this model desc…
Democritus
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7) choose the best answer. who rejected the atomic theory of leucippus …
7) Aristotle 8) Matter can be divided infinitely with its property never changing.
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5) choose the best answer. what does atomos mean according to democritu…
5) C. uncuttable, tiny particles 6) B. always in motion
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3) choose the best answer. which of the following did greek philosopher…
3. water 4. Democritus
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1) choose the best answer.which greek philosopher reasoned that it is i…
1. Leucippus 2. Matter could only be divided until you reached the smallest particle, called atomos.
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20. choose the best answer. the relationship between the mass and volum…
density
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18. choose the best answer. the smallest unit of an element that mainta…
18. atom 19. organic
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16. choose the best answer. an object in motion tends to resist a chang…
16. inertia 17. Magnetic and electric waves travel perpendicular to each other in radiation.
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16. choose all that apply. which two statements are advantages of a mod…
16. save time and money before making a product, study things that are very small 17. inorganic
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14. choose the best answer. when a substance changes in a way that does…
14. B. physical 15. B. Water is clear, D. Water has poor thermal conductivity, E. Water is polar
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12. choose the best answer. a(n)_____substance is made up of two or mor…
12. A. compound 13. C. intensive
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10. choose all that apply. which two of these are correct examples of c…
10. B. reactivity, D. flammability 11. D. Simplicity
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8. choose the best answer. when two or more substances combine to make …
8. chemical 9. extensive
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6. choose the best answer. there are 5 kg of gasoline. is the mass of t…
6. B. extensive 7. B. physical
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look at the picture. then, choose the best answers. 4. choose the best …
4. Intensive 5. Chemical
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3. choose all that apply. in order for elements to form a compound, whi…
must be in definite proportions, must chemically combine
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1. choose the best answer. which statement is true about oxygen gas, wh…
1. It is a molecule. 2. boiling point, malleability
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10) choose the best answer. margaret hutchinson rousseau was a pioneer …
chemical engineering
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8) choose the best answer. which scientist uses models to invent produc…
8) chemist 9) to understand how polyethylene behaves when shaped
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7) choose the best answer. what is the purpose of developing the follow…
to learn more about the process of forming a precipitate
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6) choose the best answer. a scientist discovers a new chemical on the …
by showing the chemical's structure
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4) choose the best answer. which type of material is the best thermal c…
4) B. metal 5) A. copper
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2. which observations serve as evidence of a chemical reaction? mark al…
- **Question 2**: - change in the color of a solution - formation of a gas - formation of a new product - **Question 3**: - chemical change: the result of a chemical reaction prod…
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checkpoint: hydrogen bonds 1 how are hydrogen bonds different from cova…
Hydrogen bonds don't involve electrons being shared or transferred.
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5) choose all that apply. which two of these are required for a compoun…
must chemically combine, must be in definite proportions
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4) choose the best answer. look at the diagram. what does the diagram s…
Hydrogen atoms are not perfectly held on opposite sides of oxygen.
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3) choose the best answer. which two of these are properties of water? …
Water has poor thermal conductivity; Water is clear.
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1) drag and drop the definitions with the terms. a substance made up of…
- "a substance made up of two or more atoms that are chemically bonded together" → molecule - "a compound that contains carbon and hydrogen" → organic compound - "a compound that …
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3. concerning chromatography, why do different colors in the ink separa…
3. Because the colors are made of different pigments that move at different speeds through the pape 4. yellow
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1. what property of the filter prevents collecting the salt? the size o…
1. The size of the filter pores versus the size of the salt grain 2. no
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9) look at the picture. then, answer the question. is being 2.5 cm long…
extensive property
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what happens to water during evaporation? it changes from a solid to a …
It changes from a liquid to a gas.
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8) look at the picture. then, answer the question. the frog is 2.5 cm l…
physical property
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7) look at the picture. then, answer the question. is density an intens…
intensive property
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6) look at the picture. then, answer the question. the density of epiba…
physical property
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5) look at the picture. then, answer the question. the frog secretes a …
chemical property
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4) look at the picture. then, answer the question. the frog is blue. is…
physical property
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3) check the box if the statement describes a chemical property or a ph…
- color: Physical property - toxicity: Chemical property - ductility: Physical property - flammability: Chemical property - reactivity: Chemical property - malleability: Physical …
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2) drag and drop the terms with the definitions. occurs when two or mor…
1. chemical change 2. density 3. extensive property 4. intensive property 5. physical change
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1) drag and drop the terms with the definitions. anything that has mass…
- "anything that has mass and takes up space" → matter - "the smallest unit of an element that maintains all of the chemical properties of that element" → atom - "a form of matter…
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17. choose the best answer. a ____ is used to explain how a chemical sh…
MSDS
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15. choose the best answer. in the middle of a chemical experiment, the…
leaving an experiment unattended # 16.
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11. choose the best answer. the base unit for volume is ____. gram lite…
11. B. liter 12. B. meter
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1. match the correct term to complete the sentence. how close a measure…
1. Accuracy 2. Precision 3. Systematic 4. Random
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which three are types of scientific research? applied commercial descri…
22. A. applied, C. descriptive, E. experimental 23. D. MSDS
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19. choose the best answer. a____ sign is used to identify whether a ch…
B. hazmat
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1. choose the best answer. in the middle of a chemical experiment, the …
1. leaving an experiment unattended 2. random 3. systematic
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2. why should wire gauze be used when heating glass containers with a g…
The glass may break when exposed to high heat, but the wire gauze prevents the glass from coming into direct contact with the flame.
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3. what are the five safety precautions (in order) that you should take…
a. Make sure that the glass tubing is not jagged, the edges should be smooth. b. Make sure you wear heavy gloves to protect your hands. If leather gloves are not available, use ru…
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4. what method is frequently used to separate a solute and solvent that…
4. evaporation 5. a. Use an evaporating dish or a crucible. b. Follow the proper procedures for using a Bunsen burner. c. Place the evaporating dish or crucible on a pipe stem tri…
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9. what is the name of the process of separating solids from liquid mix…
Filtration
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7. what instrument can you use to estimate when measuring liquids? grad…
7. beaker 8. Gently waft the air toward your nose with your hand
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5. if you need to mix water and acid, what is the proper way to mix the…
5. Add acid to water slowly 6. pipettes and burettes
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3. should you use your hands to touch chemicals? yes, only if you wear …
3. Yes, only if you wear gloves 4. Gloves
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1. the mortar and pestle should be used to _________ substances. you sh…
1. grind, one 2. Read the label and become familiar with all the safety issues relevant to handling that particular substance.
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6) type the answer in the blank. a is used to explain how a chemical sh…
6. Material Safety Data Sheet (MSDS) 7. hazard 8. labels
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5) drag and drop the laboratory scenarios with the rules. two students …
- Two students are texting and laughing while a solution burns on a Bunsen burner: Be serious in the lab. - A student is conducting a combustion experiment with fire without help:…
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4) use the graph to choose the best answer. what is a characteristic of…
room with an eyewash and chemical shower
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3) choose the best answer. look at the image. what hazard is being comm…
chemical handling
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1) choose the best answer. which of the following is a lab safety rule?…
Report damaged glassware or equipment.
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6) check the box if the statement is an error for random or for systema…
- Some of the data for the experiment was accidentally deleted from the study: Random - A chemical solution was measured with a cup instead of a beaker with measurements in liters…
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look at the math equation. then, choose the best answer. equation: 456.…
10. \(3\) 11. \(11200\ km^{2}\)
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the base unit for mass is ____. mole kelvin gram seconds meter 6. choos…
For the first question: gram For the second question: \(5.9\times10^{-4}\)
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the base unit for the amount of a substance is ____.molemeterkelvinseco…
1. mole 2. kelvin
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which of the following correctly ranks the substances below in order of…
$N_2 < F_2 < HCl < HF < LiF$
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if the molecules in 1.0 l of each of the gases, ne, cl₂, nh₃ and hcl ar…
A. \(Cl_{2}\)
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complete the following conversions using dimensional analysis. round to…
1. \(0.325\space g\) 2. \(58320\space s\) 3. \(17009700\space mg\) 4. \(220.98\space cm\)
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the van der waals equation, (nrt = (p + a(n/v)^{2})(v - nb)), incorpora…
\(CO_2\)