化學
化學反應、化學計量、分子結構與元素性質。
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the compound sodium sulfate is soluble in water. when this compound dis…
A. two $Na^{+}$ ions, C. one $SO_4^{2 -}$ ion
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the passage below describes an experiment. after a severe winter storm,…
an experimental group
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which of the following is the net ionic equation for the reaction of ca…
C. $3Ca^{2+}(aq)+2PO_4^{3 -}(aq) ightarrow Ca_3(PO_4)_2(s)$
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in class, students are asked to evaluate the electron configuration 1s²…
1. I agree with Student 1. Electrons fill the lowest energy levels first, and the given configuration \(1s^{2}2s^{2}2p^{6}3s^{2}4p^{1}\) is an excited - state configuration as the…
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4. which of the following are buffer solutions? explain you reasoning. …
a. Not a buffer. b. Not a buffer. c. Buffer. d. Buffer. For question 5: Mix approximately $0.635\ L$ of $0.100\ M\ HCOOH$ and $0.365\ L$ of $0.100\ M\ NaHCOO$ to make the buffer. …
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the passage below describes an experiment. eve was using steel to make …
the steel squares soaked in salt water and vinegar
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soda with carbon dioxide bubbles raymond wanted to freeze soda to make …
the bottles with lids taken off
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cnh2n - 2 c6h2·6 - 2 = c6h10 disuije y nombre todos los isómeros de fór…
1 - Hexino: $HC\equiv C - CH_2 - CH_2 - CH_2 - CH_3$ 2 - Hexino: $CH_3 - C\equiv C - CH_2 - CH_2 - CH_3$ 3 - Hexino: $CH_3 - CH_2 - C\equiv C - CH_2 - CH_3$ 3 - Metil - 1 - pentin…
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which best describes the location of protons in an atom? scattered thro…
First question: C. In the nucleus Second question: D. Similar electron configurations
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the atomic number of an element * 1 point equals: the number of neutron…
1. C. The number of protons 2. B. Atoms are mostly empty space 3. (Incomplete question as no valid metal option is given among the presented choices)
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the modern atomic model describes electrons as: moving in fixed circula…
1. Located in electron probability clouds 2. Group 18
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which scientists experiment led to the discovery of the electron? ruthe…
1. C. Thomson 2. C. 31
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now that we know the ph of the ocean, we can determine how much of the …
10%
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1. what is the h₃o⁺ in a solution that is 0.0515 m hno₂ and 0.120 m nan…
1. $[H_3O^+]\approx 1.9\times 10^{-4}\ M$ 2. $pH = 4.65$ 3. Mass of sodium benzoate $\approx 2.12\ g$
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study the graph based on the information in the graph, choose the state…
B. The reaction releases energy
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choose the molecule that is most concentrated at each ph. ph = 4 ph = 7…
pH = 4: $H_2CO_3$ pH = 7: $HCO_3^-$ pH = 10: $CO_3^{2 - }$
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chemical reactions convert reactants to products. in nonliving systems,…
The blanks are correctly filled as shown in the image: reactants, products, catalyst, enzymes, activation energy.
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chem 100l - introduction to chemistry laboratory - experiment #6 if uns…
Equation: $P = kT$ Verbal statement: The pressure of a fixed - mass of gas at constant volume is directly proportional to its absolute temperature.
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how will the equilibrium change if the ocean is more acidic? more hco₃⁻…
More $HCO_3^-$ is made
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how would the equilibrium change if the ocean became more acidic? more …
More $H_2CO_3$ is made
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2. in order to perform this experiment, what two experimental factors (…
For Question 4: As the absolute temperature of a gas increases, the average velocity of its molecules increases. Faster - moving molecules collide more often and with greater forc…
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which set of values tells us if the reaction is at equilibrium? a = 5.8…
C. Rate of precipitation = 2.1x10⁻⁸ M/s, Rate of dissolution = 2.1x10⁻⁸ M/s
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what can we measure with the si unit, the mole? length amount of substa…
amount of substance
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which si unit is used to measure the number of atoms in different eleme…
moles
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1) based on your answers to questions 1 through 4 on the diagram and yo…
For the HCl - NaOH titration, the percent errors for Trial 1, Trial 2, and Trial 3 are approximately \(3.33\%\), \(1.67\%\), and \(4.0\%\) respectively. The trial with the smalles…
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getting to know the periodic table how often do i make chemistry jokes?…
1. Across - 1: Mass number 2. Across - 2: Halogens 3. Across - 3: Groups 4. Across - 4: Lanthanides 5. Across - 5: Alkali metals 6. Across - 6: Liquids 7. Across - 7: Neutrons 8. …
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practice 1 the water molecules have cooled and slowed down so much that…
1. precipitation 2. condensation 3. evaporation
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occurs when the sun radiates energy on the surface which causes the wat…
B. evaporation
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1) some physical properties of two samples of iodine - 127 at two diffe…
1. C. phases of matter 2. C. an exothermic reaction 3. (Drawing instruction: Use key to draw at least five CO₂ gas - molecules spread out in the box, representing a gas phase) 4. …
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part iv - regents questions 1) which process is exothermic? a) boiling …
1. No clear question. Please clarify. 2. D. was exothermic 3. B. low intermolecular attraction 4. B. chemical, thermal, and electromagnetic 5. C. phases of matter 6. C. an exother…
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9. how are each of the substances in problem 3 alike? without knowing s…
10. a. 1s²2s²2p³ b. 1s²2s²2p⁶3s²3p³ c. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p³ 11. Valence electrons are the electrons in the outermost shell of an atom and are involved in chemical bonding. 12…
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1. the results of the gold - foil experiment led to the conclusion that…
1. d 2. b 3. a 4. d 5. a 6. a 7. c 8. b 9. c 10. c 11. a 12. a 13. c
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24 after chemotherapy, a patient notices that they bleed readily and ex…
Thrombocytopenia
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part d (4 of 7) 2 tries left after a power stroke, the myosin head must…
ATP binds to the myosin head.
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1. define a family. 2. what is a period? 3. what is the symbol for the …
1. A group of elements in the periodic table with similar chemical properties due to the same number of valence electrons. 2. A horizontal row of elements in the periodic table. 3…
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8. does a given element always have the same number of each particle? w…
No, a given element always has the same number of protons, but can have different numbers of neutrons (isotopes) and electrons (ions). For example, carbon - 12 and carbon - 14 are…
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7. for each of the following water - soluble compounds, indicate the io…
For NaI: $Na^+(aq), I^-(aq)$; For $K_2SO_4$: $2K^+(aq), SO_4^{2 -}(aq)$; For NaCN: $Na^+(aq), CN^-(aq)$; For $Ba(OH)_2$: $Ba^{2 +}(aq), 2OH^-(aq)$; For $(NH_4)_2SO_4$: $2NH_4^+(aq…
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3. write equations for the decomposition of h₂co₃ and h₂so₃. 4. at what…
3. $H_2CO_3 ightarrow H_2O + CO_2$, $H_2SO_3 ightarrow H_2O+SO_2$ 4. Cannot be determined without graph.
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12. if the actual yield of a reaction is less than the theoretical yiel…
C. All of the answers
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11. what happens to the surroundings in an exothermic reaction? a. they…
d. They gain heat from the reaction
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8. which of the following is an example of an endothermic reaction? a. …
a. Photosynthesis in plants
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mixture illustration personal definition and essential characteristics:…
Personal definition and essential characteristics: A combination of two or more substances not chemically combined, separable by physical means, retaining individual component pro…
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2. how do you calculate percent yield? a. by subtracting the theoretica…
B. By dividing the actual yield by the theoretical yield and multiplying by 100
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directions: read the passage, then answer the questions that follow. su…
6. The contents of the glass are a solution. The white powder dissolves in water to form a homogeneous mixture. 7. After the water evaporates, the powder that was dissolved in the…
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before beginning this experiment in the laboratory, you should be able …
### 1. #### (a) **Molecular equation**: $2HNO_3(aq)+K_2CO_3(aq)=2KNO_3(aq)+H_2O(l)+CO_2(g)$ **Complete - ionic equation**: $2H^+(aq)+2NO_3^-(aq)+2K^+(aq)+CO_3^{2 - }(aq)=2K^+(aq)+…
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which of these is an example of a physical change? water freezing into …
Water freezing into ice cubes
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which of these is an example of a chemical change? all of these a piece…
A. All of these
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which of these is an example of a physical change? all of these sodium …
Dissolving salt in water
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which of these is an example of a chemical change? a leaf turning green…
A. A leaf turning green in the fall
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which of these is an example of a chemical change? painting the walls g…
C. Fireworks exploding
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and net ionic equations before beginning this experiment in the laborat…
$CuCO_3$, $ZnS$ ### 3.
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multiple choice question what is the condition resulting from constrict…
C. Coronary artery disease
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what type of change occurs when a substance becomes a new and different…
C. A chemical change
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which is an indicator of a chemical change? production of gas all of th…
A. Production of gas
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when you added baking soda to a container of vinegar, bubbles were prod…
D. A chemical change
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if you are able to reverse a change, it is an indicator of ... both a c…
a physical change.
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which is an indicator of a chemical change? a color change production o…
C. ALL of these
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which type of change can sometimes be reversed? both a chemical and a p…
B. Physical change
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how is a chemical change different than a physical change? in a physica…
In a chemical change, a new substance is formed.
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which is not a quality of a non - metal? gas at room temperature poor c…
1. C. shiny 2. B. a proton
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which of these is an example of a physical change? all of these shaking…
B. Shaking a container of orange juice with pulp
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what type of change occurs when the substance you start with is the sam…
B. A physical change
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the current model of the atom is known as rutherfords model bohrs model…
- First question: Electron Cloud Model - Second question: protons and neutrons - Third question: metals
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of these three states of matter: solid, liquid, and gas, gases are the …
- First question: are highly compressible - Second question: gas - Third question: False
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in this atomic model, point d represents a proton a nucleus an electron…
For the first question: C. an electron For the second question: A. a compound
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if you break a piece of glass, the shape of the glass changes, but the …
1. C. a physical change 2. False
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question 4 which process is a physical change? rusting iron melting ice…
Question 4: melting ice Question 5: physical change
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question 2 which of these is an element? steel chlorine sugar plastic q…
Question 2: B. chlorine Question 3: A. removing heat from the water
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family column group period
period
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5. molarity, abbreviated m, is defined as the concentration of a soluti…
5. $5.025\ mL$ 6. $1.18\ g$
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physical and chemical changes identify if the actions depict a physical…
1) physical change 2) chemical change 3) chemical change 4) physical change 5) chemical change 6) chemical change 7) physical change 8) physical change 9) chemical change 10) chem…
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check the box next to each molecule on the right that has the shape of …
$\boxed{BrO_3^-, H_3O^+, NH_3, SO_3^{2 - }}$
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76 report sheet · chemical reactions of copper and percent yield questi…
1. Depending on amounts, either zinc/aluminum or copper sulfate can be the limiting reagent. For equal moles of zinc and copper sulfate, zinc is limiting. For aluminum, it depends…
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a saturated fatty acid has one double bond within the carbon chain. two…
no double bonds within the carbon chain.
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check the box next to each molecule on the right that has the shape of …
$\text{C}_2\text{H}_2$, $\text{SCN}^-$
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check the box next to each molecule on the right that has the shape of …
$\mathrm{CH_2O}$, $\mathrm{NO_3^-}$, $\mathrm{CO_3^{2 - }}$
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76 report sheet · chemical reactions of copper and percent yield questi…
1. Without specific amounts of reactants, if the amount of zinc/aluminum is less than the stoichiometrically - required amount based on the amount of $CuSO_4$, then $Zn$ or $Al$ i…
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multiple choice question ____ are receptors in the walls of the aorta a…
A. Baroreceptors
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this sketch of a neutral molecule is shaded red or blue wherever the el…
NO₂, SF₂
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electrostatic potential map possible chemical formula (check all that a…
ICl, $NO_2$, HI, HF
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electrostatic potential map possible chemical formula (check all that a…
$\ce{H2CO}$, $\ce{IF}$, $\ce{H2O2}$, $\ce{COCl2}$
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electrostatic potential map possible chemical formula (check all that a…
O₂
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this sketch of a neutral molecule is shaded red or blue wherever the el…
HF, N₂H₂, H₂CO, CO
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6) hydrogen and oxygen react to form water. select the answer that corr…
A. 2, 1, 2
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d) atp and adp contain the same amount of energy. 5) the images show ca…
5) A. Carbon has the ability to form up to four bonds. 6) 2 \(H_2\), 1 \(O_2\), 2 \(H_2O\)
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crystalline structure and properties of metals see metal is a crystalli…
The pattern is that BCC - structured metals generally have higher Young's modulus (stiffer) than FCC - structured metals. This is because BCC structures are less closely - packed,…
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conductivity and luster metals are good conductors of both heat and ele…
A rumor spreads faster in a gym where students can move around freely. The analogy is that free - moving students in a gym are like the free - moving electrons in metals that give…
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ductility and malleability two very important properties of metals are …
1. Take two metal samples of the same size and shape. 2. Use a calibrated hammer to apply a series of equal - force impacts on each sample. 3. Measure and record the thickness and…
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24 sep evaluate information graphite is a soft substance used in writin…
The different properties of graphite and carbon nanotubes are due to their distinct atomic - level structures. Graphite has carbon atoms arranged in layers with weak inter - layer…
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4. what does the main number of the atom mean? a. how many number of at…
B. number of protons
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which fat is most likely a solid at room temperature? one that is satur…
one that is saturated
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sep evaluate information graphite is a soft substance used in writing i…
Vial A contains an ionic solid. Vial B contains a molecular solid. Vial C contains a covalent network solid.
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analysis 1. what is an electron? 2. what is an electrons ground state? …
1. An electron is a negatively - charged sub - atomic particle. 2. The ground state of an electron is its lowest energy configuration. 3. By absorbing energy (e.g., heat or light)…
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23 sep construct an explanation use compound type to infer the relative…
$N_2O < H_2O < NaF$
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to measure the difficulty of the science experiment, dr. kitts and dr. …
B. challenging life - conditions
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directions: using the periodic table find the number of protons, neutro…
# Explicación: ## Paso 1: Obtener número de protones de oxígeno El número atómico de oxígeno es 8, por lo que el número de protones es 8. ## Paso 2: Obtener número de electrones d…
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10/14 u1 quiz - vocabulary match the following words with their definit…
molecule - a group of atoms bonded together compound - a substance made up of two or more elements element - a pure substance that cannot be broken down into simpler substances ch…
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for helium, how many electrons in the first shell are required for stab…
# Explicación breve: La capa electrónica K (primera capa) puede容纳 un máximo de 2 electrones. El helio tiene 2 electrones en su primer nivel de energía y es estable. # Respuesta: C…
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the ______ rule explains that atoms with fewer than 8 electrons in thei…
# Breve explicación: El octeto es la regla que establece que los átomos con menos de 8 electrones en su capa externa intentarán compartir, ganar o perder electrones para alcanzar …
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the ______ shell must be full in order for the atom to be stable. outer…
outermost