化学
化学反应、化学计量、分子结构与元素性质。
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why are transition states associated with such high energies? they are …
They are held together by very unstable bonding between reactants and products.
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what is the enthalpy, $delta h$, for this reaction? -30 j 50 j -80 j 30…
-30 J
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reaching the transition state in a chemical reaction is more likely und…
Higher temperature and higher concentrations of reactants
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combustion analysis 2) 33.658 g of oxygen was used to completely react …
Empirical formula: $C_5H_8$; Molecular formula: $C_{15}H_{24}$
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1. name the three subatomic particles unit 1 exam 2. fill in the follow…
1. Protons, neutrons, electrons 2. Table is already filled correctly as shown 3a. Protons: 29, Electrons: 27, Type of ion: Cation 3b. Protons: 52, Electrons: 54, Type of ion: Anio…
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3. a compound consists of 52.14 % carbon, 13.13% of hydrogen, and 34.73…
$C_{6}H_{18}O_{3}$
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3. a compound consists of 52.14% carbon, 13.13% of hydrogen, and 34.73%…
The empirical formula is $C_2H_6O$
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1. determine the percentage composition of al2(co2)3.
Percentage of Al is approximately 23.06%, percentage of C is approximately 15.39%, percentage of O is approximately 61.53%
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this picture shows how atoms are arranged in a ____ gas solid
gas
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1. determine the percentage composition of al2(co3)3. 2. a compound con…
$C_{12}H_{36}N_{4}$
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this picture shows how atoms are arranged in a gas liquid
Neither gas nor liquid (but most similar to a solid - like arrangement if considering the given options)
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this picture shows how atoms are arranged in a liquid solid
liquid
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4 fill in the blank 1 point please determine a reasonable formula for a…
$SiO_{2}$
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1. write the complete, balanced equation for the reaction of hno3 and n…
1. $HNO_3(aq)+NaOH(aq) ightarrow NaNO_3(aq)+H_2O(l)$ 2. $0.115\ M$
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what is the main concern about toxic chemicals in the oceans? they are …
They can bioaccumulate and enter the food chain
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11. what is the mass of 30,000 molecules? express your answer in scient…
$1.59\times 10^{-18}$ grams
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match each vocabulary word from the reading passage with the correct de…
1. g. mild - mannered, kind, or tender 2. j. strain out unwanted material 3. e. distinctive; special 4. b. microscopic organisms that float in the sea, which many larger animals d…
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which of these best explains why second - hand smoke is especially dama…
The non - smokers do not even get the advantage of having a filter for the smoke that they breathe.
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23 refer to the graph below. which statement below best explains reacti…
C. Reaction 3 most likely occurred in the presence of an enzyme.
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bromine and mercury are the only elements that are liquid at room tempe…
medium strength
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a compound has a very low boiling point of -25 °c. what describes the i…
The attractions are weak and allow the molecules to boil easily.
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you test 3 liquids for their surface tension by adding drops onto a pen…
Liquid 2
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which substance has the weakest attractive forces based on the provided…
The molecule with the fewest number of carbon and hydrogen atoms among the given options. If the options are \(C_{2}H_{6}\), \(C_{4}H_{10}\) and \(C_{6}H_{14}\), the answer is \(C…
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consider the elements below. rank them from lowest to highest attractiv…
$H_2$, $Br_2$, $Mg$
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which of the following diagrams correctly shows the reaction pathway of…
The diagram where the energy of the products is greater than the energy of the reactants correctly shows the reaction pathway of a reaction that absorbs energy. Without seeing the…
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3. why does ice float? draw a diagram of liquid water vs solid water to…
Ice floats due to its lower density compared to liquid water. A diagram would depict ice with a more open, lattice - like structure and liquid water with more closely arranged mol…
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1. which diagrams represent a compound? each color represents
The first and fourth diagrams (the ones with blue - red pairs and blue - gray combinations respectively) represent compounds as a compound is a substance made up of two or more di…
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9/22 water pollution and the flint water which is not one of the ways t…
Treating with lead - removal filters
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9/22 water pollution and the flint water crisis according to the video,…
The best definition is "Chemicals and debris that is washed into lakes/rivers/streams by precipitation and runoff".
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9/22 water pollution and the flint water crisis according to the video,…
Chemicals and debris that is washed into lakes/rivers/streams by precipitation and runoff.
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type the element in each list with the largest atomic mass:
N At Te Cl
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pieces of plastic smaller than 5mm; have been found to accumulate in an…
1. B. microplastics 2. A. fatty tissues 3. C. Satisfying basic needs without depleting or degrading resources
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identify the number of valence electrons found in each element.
K: 1, Ca: 2, Ne: 8, P: 5, C: 4, Br: 7, Al: 3, S: 6
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**19. what is a buffer?** a) a molecule that stores genetic information…
19. c) A solution that resists changes in pH when acids or bases are added 20. d) Hydroxyl group 21. b) Amino group
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15. what is the number of hydrogen atoms in the compound c6h12o6? a) 6 …
15. b) 12 16. c) Oxygen atom 17. d) Ability to form hydrogen bonds 18. d) The concentration of hydrogen ions in a solution
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14. which of the following is a balanced version of this equation: h2 +…
A. $2H_2 + O_2 ightarrow 2H_2O$
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**11. an isotope has the same number of:** a) protons but a different n…
11. d) Protons but a different number of neutrons 12. a) All of the above 13. a) Reactants
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7. which type of bond involves the sharing of electron pairs between at…
B. Covalent bond
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exam 1- requires respondus lockdown browser final grade 64.5/100.5 subm…
B. $2000\text{ }\mu\text{g}$
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daltons theory states that atoms are the smallest possible parts of ele…
rearrange and form new substances with new properties.
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5 all organic compounds contain which of the following elements? (1pt) …
C. Carbon
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3. in a controlled experiment, which variable is deliberately changed? …
3. c) Independent variable 4. d) Proton 5. c) The number of protons 6. d) 12
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an atoms emission of light with a specific amount of energy confirms th…
electrons emit and absorb energy based on their position around the nucleus.
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3 which property of water causes the meniscus shown in the image below?…
C. adhesion
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which scientist and atomic model are correctly matched? o bohr - plum p…
Schrödinger - electron cloud surrounds nucleus
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endothermic a reaction in which energy is absorbed by reactants exother…
- What happened to the heat in the surroundings? Heat was absorbed by the reaction from the surroundings. - Did an endothermic or exothermic reaction occur? An endothermic reactio…
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the current atomic model has a o clear and exact placement for every el…
predicted area surrounding the nucleus where the electron could be located.
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it takes 614 kj/mol to break a carbon - carbon double bond. calculate t…
195 nm
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electronic structure and chemical bonding interconverting wavelength, f…
$819\ nm$
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endothermic a reaction in which energy is absorbed by matter exothermic…
- Endothermic Reactions: less - Exothermic Reactions: more - What happened to the heat in the surroundings: Heat was absorbed by the reaction from the surroundings. - Did an endot…
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it takes 146. kj/mol to break an oxygen - oxygen single bond. calculate…
$820\ nm$
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it takes 945. kj/mol to break a nitrogen - nitrogen triple bond. calcul…
127 nm
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exothermic reaction: a chemical in which thermal energy is. the product…
Exothermic Reaction: a chemical reaction in which thermal energy is released. The products will usually feel hot. The products will have lower energy than the reactants. More chem…
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re - order each list in the table below, if necessary, so that the atom…
$Br^-, Cl^-, F^-$ $S^{2 - }, S, Cl$ $Na, Mg, Mg^+$
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the table below shows the freezing points of four substances. substance…
butane, nitrogen
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exothermic reaction: a chemical thermal energy is the products will usu…
Exothermic Reaction: a chemical reaction in which thermal energy is released. The products will usually feel hot. The products will have lower energy than the reactants. More chem…
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a 1 - l soda bottle contains dissolved carbon dioxide gas. which bottle…
a bottle that is sealed
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which term refers to a property that depends only on the amount of a su…
extensive
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re - order each list in the table below, if necessary, so that the atom…
$Na$, $Mg$, $Mg^+$ $Br^-$, $Br$, $Cl$ $Na$, $Al$, $Ar$
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a chemist is studying an unknown substance and could break the substanc…
pure substance
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which heterogeneous mixture contains large particles that can settle ou…
D. suspension
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re - order each list in the table below, if necessary so that the atoms…
B, Be, B²⁺ Li, B, F Br⁻, Cl⁻, F⁻
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what type of mixture scatters light and cannot be filtered easily? a co…
A. a colloid, a heterogeneous mixture
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why do reactions occur? during a chemical reaction, the ____ form produ…
During a chemical reaction, the **atoms** form products when chemical **bonds** in the reactants break and form **new bonds** in the products. All reactions involve a **change** i…
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what is the name of a solution whose concentration of solute is equal t…
saturated
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which physical method can be used for obtaining a sample of salt from a…
boiling
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a student is using a copper strip and a strong chlorine solution in her…
reactivity of the copper strip
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understanding periodic trends in atomic size re - order each list in th…
B, C, O F⁻, F, Ne I⁻, Br⁻, F⁻
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electronic structure and chemical bonding interpreting the electron con…
1. Cl⁻ 2. 18 3. 6
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9. what is thermochemistry? 10. if energy in the system (reactants) dec…
9. The study of heat changes in chemical reactions and physical state - changes. 10. Released to the surroundings. 11. Exothermic change. 12. Absorbed from the surroundings. 13. E…
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10. if energy in the system (reactants) decreases, where does the energ…
10. The energy is transferred to the surroundings. 11. Exothermic change. 12. The energy is absorbed from the surroundings. 13. Endothermic change. 14. Left: exothermic; Right: en…
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air is made up of different gases, such as oxygen, nitrogen, and carbon…
Oxygen, nitrogen, and carbon dioxide are all classified as pure substances.
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an atomic anion with a charge of - 2 has the following electron configu…
What is the chemical symbol for the ion? \(O^{2 -}\) How many electrons does the ion have? 10 How many 2s electrons are in the ion? 2
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which is true about the dissolving process in water? polar solutes do n…
Water molecules are attracted by solute ions at the surface of the solute; Water molecules move throughout the solute.
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which statement describes an intensive property of matter? it is the sa…
It is the same for every sample of a single substance.
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which substance is a mixture? o table salt o gasoline o aluminum o carb…
gasoline
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which process is a chemical change? burning a match boiling water melti…
burning a match
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which pure substance can be classified as an element? o h₂ o no₃ o nacl…
$H_2$
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the table below shows four samples of carbon dioxide gas and the temper…
1
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an atomic cation with a charge of + 1 has the following electron config…
1. \(Al^{+}\) 2. 13 3. 1
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which rock type is formed through the cooling and solidification of mag…
1. C. Igneous 2. B. It breaks rocks into smaller pieces without changing their composition
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what should this mixture be classified as? colloid compound solution su…
suspension
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a neutral atom has the following electron configuration: he 2s²2p⁴. wha…
What is the chemical symbol for the atom? O How many electrons does the atom have? 8 How many 2s electrons are in the atom? 2
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which statements are true of heterogeneous mixtures? 1) they settle out…
1 and 2
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name eniza roya stemscopedia: energy in chemical reactions reading guid…
1. Remove heat. 2. a. Combustion of wood b. Rusting of iron 3. Melting of ice 4. Energy from the movement of atoms and molecules within a substance. 5. A chemical reaction or proc…
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a chemical engineer must report the average volume of a certain polluta…
$4.8$
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which plate boundary results in a mid - ocean ridge? (1 point) converge…
1. C. Divergent - Oceanic & Oceanic 2. B. The physical breaking of rocks into smaller pieces without changing their composition
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what happens at transform plate boundaries? (1 point) plates move apart…
1. Plates move sideways past each other 2. Frost wedging in rock cracks
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which factor causes a decrease in the rate of dissolution? decreasing t…
decreasing the surface area of the solute
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how did research conducted on polluted drinking water in flint, michiga…
The amount of harmful chemicals in the water was reduced.
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a chemical engineer must report the average volume of a certain polluta…
6.83 L
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a chemistry student must write down in her lab notebook the concentrati…
$0.105\ g\cdot mL^{-1}$
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a chemical engineer must report the average volume of a certain polluta…
$25.1$
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1. name the three subatomic particles. 2. fill in the following table u…
1. Protons, neutrons, electrons 2. P: Protons 15, Neutrons 16, Electrons 15; Sb: Protons 51, Neutrons 71, Electrons 51; Ne - 20: Protons 10, Neutrons 10, Electrons 10 3. Cu⁺: Prot…
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a chemical engineer must report the average volume of a certain polluta…
7.1 L
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solution equals the mass of whats dissolved divided by the total volume…
$0.2964\ g\cdot mL^{-1}$
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a student is analyzing data from a density experiment. the student reco…
1.52 g/mL
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a student is analyzing data from a density experiment. the student reco…
A. 2.98 g/mL x 10⁻¹
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6. draw a line matching the following elements to the different groups …
6. Radium - Alkaline Earth Metal; Iodine - Halogen; Krypton - Noble Gases; Lithium - Alkali Metal 7. Tungsten 8. Antimony has a higher effective nuclear charge because it has more…
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a chemistry student must write down in his lab notebook the concentrati…
$0.465\ g\ mL^{-1}$