化學
化學反應、化學計量、分子結構與元素性質。
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2. rhenium, re, is one of the rarest elements on earth. alloys containi…
The abundance of Re - 185 is approximately $37.3\%$ and the abundance of Re - 187 is approximately $62.7\%$.
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4. a chemist has 70 ml of a 50% methane solution. how much of a 80% sol…
35 mL ### 5.
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read the excerpt from a story. “oops! oh, no...” jenna eyed the spill a…
It changes from a student's perspective to her teacher's perspective.
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the mass spectrum of a sample of a pure element is shown above. calcula…
The average atomic mass is approximately 39.03. To identify the element, we look up this value on the periodic - table. The element with an average atomic mass close to 39.03 is p…
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2. a 0.244 g sample of calcium carbonate, caco₃, was recovered from a s…
0.00244 formula - units
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read the list of color groups and schemes and enter each in the box nex…
primary colors: C. red, yellow, blue secondary colors: D. orange, green, violet intermediate colors: A. yellow - orange, blue - violet complementary colors: B. orange and blue, re…
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1. how many moles of lead (ii) iodide, pbi2, are there in a 25.0 gram s…
3.26×10²² atoms
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hydrolysis dehydration synthesis correctly identify what is occurring i…
hydrolysis
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match 6 points. correctly match the terms to the description. water is …
Water is a reactant of the reaction - hydrolysis Water is a product of the reaction - dehydration synthesis
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multiple choice 17 points. correctly identify what is occurring in the …
hydrolysis
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select the correct answer. what is the main purpose of the accuplacer e…
A. It provides information about the student's present academic skill levels in reading, writing, mathematics, and computer - related areas.
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how do architects use math to ensure that their buildings are not just …
The question encourages the reader to challenge preconceptions they might have about math being irrelevant to standards of beauty.
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read this appeal: meat today is filled with toxins, and cows are treate…
B. A registered nurse
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read the passage. although its not a new concept, using goats to elimin…
It counters the positive attributes of goatscaping outlined in the first paragraph with reasons for skepticism about its general effectiveness.
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which statement best describes the amount of catalyst that remains at t…
The amount of catalyst is the same at the end as at the beginning of the reaction.
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what must happen before a chemical reaction can begin? the activation e…
The activation energy must be reached.
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which is the best definition of activation energy? the energy required …
the energy required to form or break the bonds of reactant molecules
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17. how many grams of fe are there in 65.2 grams fecl₃?
22.4 g
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comprehension questions on atoms and elements 1. describe how the atomi…
1. The atomic number is determined by the number of protons in the nucleus. It signifies the element's identity and position in the periodic table. 2. The mass number is usually t…
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16. how many grams of cl₂ are there in 65.2 grams fe?
124 g
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15. how many grams of cl₂ are there in 5.25 grams fecl₃?
3.45 g
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14. how many grams of cl₂ are there in 1.25 mol cl₂?
88.625 g
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13. how many moles of cl₂ are there in 45.8 mol fecl₃?
68.7 mol
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multiple - choice question true/false: in a chemical change, chemical b…
True
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fill in the blanks using the word bank. elements, mixtures, compound, s…
16. symbols 17. periodic table 18. compound 19. pure 20. carbon dioxide 21. properties
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12. how many moles of fe are there in 12.0 grams cl₂?
The question as - is has insufficient data to find moles of Fe. If considering reaction stoichiometry, more information is needed.
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answer the questions in the table below about the shape of the xenon te…
6; Octahedral
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5. what is the relationship between the kinetic energy of molecules and…
6. Na 7. Copper 8. Pb 9. Tungsten 10. Iron 11. Tin 12. K 13. Gold 14. Hg 15. Silver
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11. how many grams of cl2 are there in 7.25 mol fecl3?
761.03 g
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multiple - choice question true/false: during a physical change the che…
False
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fast - paced songs often energize listeners, while slow, mellow tunes t…
It suggests that music can be strategically used to influence mood.
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10. how many moles of fe are there in 2.50 mol fecl3?
2.50 mol
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1. matter is anything that has mass and volume. the 2 states of matter …
1. Matter 2. Liquid, Solid 3. Physical, Chemical 4. Physical 5. Higher kinetic energy corresponds to more fluid - like physical state.
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9. how many grams of cl2 are there in 1.50 mol fecl3?
159.525 g
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for nos. 9 - 17, refer to the equation below: given: ____ fe + ____ cl2…
9. 159.54 g 10. 2.50 mol 11. 771.43 g
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reggie wants to test the effect of salt on the boiling point of water. …
b) the boiling point temperature of the water
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reggie wants to test the effect of salt on the boiling point of water. …
a) the salt added to water
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post - lab questions: 1. use the word polar or nonpolar to complete the…
polar
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8. how many grams of h₂ are there in 2.50 grams nh₃? 1st grams a to mol…
0.444 g H₂
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7. how many moles of nh₃ are there in 2.80 grams n₂? (1st grams a to mo…
0.2 mol
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directions: fill in the following table with what kind of energy each o…
| Example | Type of energy | |--|--| | 3. a flying bird | Kinetic energy | | 4. a burning candle | Chemical energy (being converted to light and heat) | | 5. a battery | Chemical …
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question 3 of 20 a nurse is assessing a preschool - age client whose pa…
B. biochemical
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are any of them s orbitals? yes no list the s orbitals, if any. are any…
Are any of them s orbitals? yes List the s orbitals, if any. A Are any of them p orbitals? yes List the p orbitals, if any. B, C
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change 1 is: impossible, a physical change, a chemical change; change 2…
Change 1 is: a physical change Change 2 is: a chemical change Change 3 is: a physical change
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multiple - choice question the center of the atom has: protons and neut…
protons and neutrons
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draw the lewis dot diagram for a s⁺ cation.
The Lewis - dot diagram has the symbol 'S' with 5 dots around it.
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question 17 mercury has a density of 14.58 g/ml. the specific gravity o…
14.58
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read the story. the ancient woman had lived alone in the cave by the se…
None of the above options are correct.
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a student sets up and solves the following equation to solve a problem …
$1.01$ g
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multiple - choice question the center of the atom is called the: subato…
B. nucleus
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review your observations of the behavior of the cube in each liquid. su…
A. Methanol and water B. Ethylene glycol and water
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question 14 cobalt has a density of 12.5 g/ml. 675ml of cobalt weighs b…
8438
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the smallest thing that can be called an element is an _______ compound…
atom
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a sample of an unknown compound is vaporized at 110. °c. the gas produc…
$50.5\ g/mol$
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a student sets up the following equation to solve a problem in solution…
mol
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select the correct text in the passage. a writer is using the following…
In many ways, Isadora Duncan can be considered the founder of modern dance. Her work showed that the natural movements of the body create the most potential for beautiful choreogr…
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c) the type of chemical used d) the time taken to complete the reaction…
c) To ensure that the experiment is fair and the results are valid
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the polypropylene cubes have a density of 0.946 grams per milliliter. i…
B. The cube floats on water because the water’s density is greater than the cube’s density. C. The cube sinks in methanol because methanol’s density is less than the cube’s densit…
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1. open - ended questions: answer the following questions in complete s…
1. L'indépendance des variables est cruciale pour isoler l'effet de la variable indépendante sur la variable dépendante. Exemple : étude de la croissance des plantes en fonction d…
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what happens if you cut an element into the smallest pieces possible? y…
You have an atom
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an atom has 20 electrons and 20 neutrons. assume it has a net charge of…
40
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the scientific method is a systematic approach used by scientists to ex…
Fill in the Blank: 1. indépendente 2. dépendante 3.Constantes 4. indépendante 5. dépendante Multiple - Choice Questions: 1. c) To be manipulated 2. a) It changes during the experi…
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the diagram shows the structure of a molecule of sulfur dioxide. the ra…
12
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negatively charged subatomic particles that have almost no mass are cal…
electrons
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a scientist conducts a procedure that causes nitrogen atoms to gain neu…
B. isotopes of nitrogen
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what is used to separate mixtures into their pure components? a macerat…
B. Distillation, D. Filtration
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because oxygen is more electronegative than hydrogen, the water molecul…
D. polar
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question 4 a pure substance composed of two or more different elements …
A pure substance composed of two or more different elements chemically combined is known as a compound.
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question 7 listen the smallest particle of an element that retains its …
atom
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44 multiple choice 2 points in patients with lactose intolerance, _____…
chemical digestion of carbohydrates
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regardez le dessin. complétez la phrase avec le nom de létudiant(e), du…
1. Marie porte un jean et une chemise blanche. 2. Inès porte un short beige et des sandales beiges. 3. Marie (assuming a student with hat and coat in the picture) porte un chapeau…
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the area around a nucleus where an electron is most likely to be found …
orbital
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43 multiple choice 2 points the portion of the small intestine that per…
B. duodenum
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when atoms gain or lose electrons, they can become negatively or positi…
D. Ions
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16 identify the reactants in the following chemical equation 6 h₂o + 6 …
16. Water ($H_2O$) and carbon - dioxide ($CO_2$) 17. Breaking and forming 18. 14 19. Decrease 20. Product 21. Atoms 22. Adhesion 23. Activation energy 24. Carbohydrates 25. Amino …
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what role does water play in chemical weathering? a. it absorbs heat fr…
1. d. It dissolves minerals 2. a. Freeze - thaw cycles
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protons: 8 neutrons: 9 electrons: 8 what is the total charge?
0
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protons: 8 neutrons: 9 electrons: 10 what is the total charge?
-2
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match the people to their contribution match term definition 1. james c…
1. F 2. H 3. A 4. B 5. D 6. G 7. E 8. C 9. J 10. I
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what is the mass number?
4
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8. name the element which has the following number of particles: a. 26 …
a. Iron (Fe) b. Iodine (I) c. Helium (He) d. Calcium (Ca) e. Lead (Pb) f. Hydrogen (H)
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find the element:
He (Helium)
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find the element: protons: 8 neutrons: 9 electrons: 10
O
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find the element: protons: 5 neutrons: 5 electrons: 5
Boron (B)
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find the element: is it: neutral atom ion
Neutral Atom
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find the element:
He
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atom a 1. how many protons are in atom a? 2. how many neutrons are in a…
a. Iron (Fe) b. Iodine (I) c. Helium (He) d. Calcium (Ca) e. Lead (Pb) f. Hydrogen (H)
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g h2 to mol h2 using atomic mass of h2 mol h2 to mol h2o using balanced…
Limiting reactant: $O_2$ Excess reactant: $H_2$ Mass of $H_2O$ produced: $11.3g$
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warm up limiting reagent show your solution/ work (no work / solution =…
Limiting reagent: $O_2$, Excess reagent: $H_2$
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in chemistry, how does an orbital get its name? because it contains par…
because it contains particles that move around the nucleus
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a substance causing a quicker reaction a prolonged period of time to ma…
| Term | Technical Meaning | |--|--| | enhelm | No common relevant meaning in given contexts | | parchment | A kind of paper made out of animal hide | | catalyst | A substance cau…
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question 7 pas encore répondu noté sur 1,00 selon le modèle atomique, l…
atomes, impossible
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question 5 quel est lunité de base de la matière? ○ a. atome ○ b. adn ○…
A. atome
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question 2 tous les atomes dun même élément sont _, ils ont les mêmes _…
identiques, caractéristiques
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question 1 il y a des atomes impliqués dans une odeur ○ a. faux ○ b. vr…
b. Vrai
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6) 2znso4 # of molecules: 2 # of elements: 3 name of element: zn=zinc s…
subscript
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9) na₂cro₄ # of molecules: 1 # of elements: 3 name of element: # of ato…
Name of element: Sodium, Chromium, Oxygen # of atoms: 2, 1, 4 Total # of atoms: 7 The #4 is a subscript.
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1. which state of matter are atoms moving the slowest? a. solid b. liqu…
# Breve explicación: En la física, las partículas en un sólido tienen una movilidad limitada y oscilan en torno a una posición fija. En un líquido, las partículas se mueven más li…
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9) na2cro4 # of molecules: 1 # of elements: 3 name of element: na= cr= …
# of molecules: 1 # of elements: 3 Name of element: Na, Cr, O # of atoms: Na = 2, Cr = 1, O = 4 Total # of atoms: 7 The #4 is a subscript
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11) pb(no3)2 # of molecules: 1 # of elements: 3 name of element: # of a…
Name of element: Lead, Nitrogen, Oxygen The #3 is a subscript