化学
化学反应、化学计量、分子结构与元素性质。
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1. what is the term that refers to the process of adding hydrogen to un…
1. D. hydrogenation 2. C. the process by which starch granules are cooked: they absorb moisture when placed in a liquid and heated 3. D. emulsify
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what is true of valence electrons? - they exist in the outer orbital. -…
A. They exist in the outer orbital.
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read the excerpt from act 1, scene 3, of julius caesar. cassius. and wh…
Cassius portrays Caesar as a cruel-hearted tyrant, and at the same time says he pities Caesar because Caesar can't help himself.
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match the items. biosphere atmosphere geosphere hydrosphere all of eart…
s: #### 1. Matching: - Biosphere: Includes the presence of living organisms of any type - Atmosphere: The envelope of gas surrounding the planet - Geosphere: Includes a hot and mo…
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a nurse is planning care for a client who is receiving chemotherapy and…
- Infuse the medication 30 min prior to chemotherapy. - Infuse the medication slowly over 15 min. - Repeat the dose 4 hr after chemotherapy.
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to determine the theoretical yield from a given chemical reaction, you …
The correct option is the one with "use the balanced chemical equation and g of a reactant to calculate the g of a product" (the fourth option in the list).
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____ is a technique to physically separate a heterogeneous mixture of a…
Filtration (the option with text "Filtration")
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in the stoichiometry lab, students performed a saponification lab using…
The ionic carboxylate end is soluble in nonpolar substances; whereas the long nonpolar hydrocarbon chain is soluble in water.
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what is the percent yield of the reaction 4 al + 3 o₂ → 2al₂o₃ if 2.8 g…
65% (Option: 65%)
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what is the theoretical yield of pi₃ if 32.0 g of i₂ are reacted with a…
34.6 g
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calculate the mass in grams of iodine (i₂) that will react completely w…
292
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calculate the mass of sodium chlorate that is used to form 7.5 g of oxy…
17
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silicon tetrachloride (sicl₄) can be prepared by heating si in chlorine…
1.45
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which of the following equations best represents the reaction shown in …
4A + 2B → 4C + 4D (the first option)
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which of the following descriptions is least likely to describe the rea…
A. A saponification reaction is similar to a combination reaction because two smaller molecules are combined to form a much larger molecule.
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a student performed a chemical reaction in lab and obtained 2.5 g of pr…
77% (corresponding to the option with 77%)
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select the correct statement below regarding actual versus theoretical …
The correct statement is: "Theoretical yield is the amount of product predicted by the balanced chemical reaction when all of a reactant has reacted." (The second option in the li…
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calculate the mass of sodium chlorate that is used to form 6.5 g of oxy…
14
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question 5 of 8 (1 point) | question attempt: 1 of 1 stearin glycerol 3…
1:3 (the option with the blue dot, i.e., the selected option is 1:3)
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in the stoichometry lab, a saponification reaction is used to calculate…
\(1:3\)
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the chemical formula for hydrogen fluoride is hf. a chemist determined …
\(1.60\space g\) (or more precisely \(1.60064\space g\) which can be rounded to \(1.60\space g\) considering significant digits)
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the movie below shows some molecules in a tiny sample of a mixture of g…
Since the problem description is incomplete (it just shows a diagram of gas molecules and a key but no specific question), we can't provide a solution yet. Please provide the spec…
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two reactants + two reactants → one product + two products (diagrams of…
The left reaction (with reactants A and B forming product AB) is a synthesis (combination) reaction, where two reactants combine to form one product. The right reaction has two re…
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which of the following images represents a single - replacement reactio…
The reaction with reactants \(A\) and \(BC\) (the right - hand side reaction in the diagram) represents a single - replacement reaction.
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question: based on the videos, what is the best definition for stoichio…
The determination of the proportions in which elements or compounds react with one another.
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question: based on the videos, what is the best definition for stoichio…
The determination of the proportions in which elements or compounds react with one another.
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13. 76g 2ag₂o → 48g 4ag + ____o₂ 14. ____s₈ + 107g 12o₂ → 352g 8so₃ 15.…
13. $28\ \text{g}$ 14. $245\ \text{g}$ 15. $731\ \text{g}$ 16. $281\ \text{g}$ 17. $130\ \text{g}$ 18. $178\ \text{g}$ 19. $404\ \text{g}$ 20. $703\ \text{g}$ 21. $46\ \text{g}$ 2…
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should do: law of conservation of mass practice pg. 13 1. ____n₂ + 47g …
1. $\boldsymbol{16\ \text{g}}$ 2. $\boldsymbol{42\ \text{g}}$ 3. $\boldsymbol{61\ \text{g}}$ 4. $\boldsymbol{21\ \text{g}}$ 5. $\boldsymbol{1\ \text{g}}$ 6. $\boldsymbol{26\ \text…
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section 4: full balancing challenge (show mastery) this is where everyt…
1. $2\text{H}_2 + \text{O}_2 ightarrow 2\text{H}_2\text{O}$ 2. $\text{N}_2 + 3\text{H}_2 ightarrow 2\text{NH}_3$ 3. $2\text{Na} + 2\text{H}_2\text{O} ightarrow 2\text{NaOH} + \tex…
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ction 3: adding coefficients (fix it—the legal way) do not change subsc…
3. $2\text{H}_2 + 1\text{O}_2 ightarrow 2\text{H}_2\text{O}$ 4. $4\text{Al} + 3\text{O}_2 ightarrow 2\text{Al}_2\text{O}_3$ 5. $1\text{Ca} + 2\text{H}_2\text{O} ightarrow 1\text{C…
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4. gulli o‘simi lkl arn i ng hayot sikli modelini yasang: a) a3 o‘lcham…
To complete this task, follow these steps: 1. For part (a), draw a schematic of the flower life cycle including stages: seed → germination (seedling) → mature plant → flowering → …
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intermolecular forces: forces of polar bonds have a difference in elect…
1. Hydrogen Bonding blanks: partial positive of the **hydrogen (H)** is attracted to the partial negative of the **oxygen (O)** of a different water molecule 2. NaCl dissolving in…
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determine the value of $\\delta s_{sur}$ at 213 k, and predict whether …
$\Delta S_{surr} = -99.3\ \text{J/K·mol}$, nonspontaneous. (Corresponding to the option: $\boldsymbol{\Delta S_{surr} = -99.3\ \text{J/K·mol}, nonspontaneous}$)
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determine the value of $\\delta s_{sur}$ at 298 k, and predict whether …
$\Delta S_{sur} = -71.0\ \text{J/K·mol}$, nonspontaneous (the option corresponding to this is the last one with $\Delta S_{sur} = -71.0\ \text{J/K·mol}$, nonspontaneous)
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determine the value of $\\delta s_{sur}$ at 298 k, and predict whether …
$\Delta S_{\text{sur}} = -71.0\ \text{J/K·mol}$, nonspontaneous
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2.1.8 quiz: analyze themes in literature question 5 of 10 read these li…
A. abbcb
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3. use your graph to determine the % ethanol in your diluted unknown wi…
The % ethanol in the diluted unknown wine sample is approximately 11.4% (or $x \approx 0.114$ when expressed as a decimal proportion)
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describe the habitability of planets which statement accurately describ…
B. The terrestrial planets (except Earth) and the gas giants are not habitable.
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6. ions -1 nitrogen gain 3 electrons nitrogen # protons: ______ # proto…
### Left (Neutral Nitrogen): # Protons: 7 # Neutrons: 7 # Electrons: 7 Ion: Neutral (N) ### Right (Nitrogen Ion): # Protons: 7 # Neutrons: 7 # Electrons: 10 Ion: $\text{N}^{3-}$ (…
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7. ions -2 nitrogen lose 2 electrons nitrogen # protons: ______ # neutr…
### Left (Neutral Nitrogen): # Protons: 7 # Neutrons: 7 # Electrons: 7 Ion: Neutral (no charge, N) ### Right (Nitrogen Ion): # Protons: 7 # Neutrons: 7 # Electrons: 5 Ion: Nitroge…
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how do rock types contribute to the rate of weathering? ○ porous minera…
A. Porous minerals weather faster.
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john dalton’s theory described the atom as a. being like plum pudding b…
B. being solid and indivisible
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which set of coefficients correctly balances the following reaction? __…
B. 3, 8, 8
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iron (iii) oxide is the main source of iron for the steel industry and …
A. FeO and Fe₂O₃
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an individual cation from the iron (iii) oxide compound would contain _…
26 protons and 23 electrons
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use the following information to answer the next question phosphorus is…
Phosphorus has 5 valence electrons, and is found in group 15 (or 5) on the periodic table.
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use the following information to answer the next question 1. ductile 2.…
1, 4, 8
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use the following information to answer the next question the following…
chlorine: 4, scandium: 1, boron: 1, gold: 3
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use the following information to answer the next two questions the high…
C. 29 protons, 29 electrons, 35 neutrons
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in which reaction does a precipitate form? a. agno₃(aq) + nh₄no₃(aq) → …
B. $\text{Fe(NO}_3\text{)}_2\text{(aq)} + \text{Na}_2\text{S(aq)} ightarrow$
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if a calcium atom were to lose electrons and become a cation, it would …
20 protons and 18 electrons
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decide what kind of crystalline solid each element or compound in the t…
### For $\boldsymbol{\ce{H2O}}$: #### Step 1: Determine the type of solid $\ce{H2O}$ is a covalent compound composed of molecules (each $\ce{H2O}$ is a molecule), so it forms a **…
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a pure solid sample of substance x is put into an evacuated flask. the …
100 ### Second Question: Phase after 22 kJ/mol Heat
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water is a polar molecule. what does this mean in terms of the structur…
- the two sides of water have different charges - it can form hydrogen bonds with other molecules including itself - oxygen has a higher electronegativity than the hydrogen atoms …
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why do water molecules form crystalline lattice structures when water f…
The correct option is: "Like charges repel and opposite charges attract. This way the oxygen will be far away from each other since they are like charges." ### Question 12 (chemic…
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the freeze thaw action of weathering is due to waters different densiti…
True ### Question 10 (Why ice is less dense than water)
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what is the best explanation for why the stream of water was attracted …
The uneven distribution of the electrons in the water molecule are attracted to the charged balloon. ### Question 6 (Property of water dissolving many substances)
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why do oil and water separate after being mixed? - water and oil are bo…
C. Water is polar and oil is non - polar. The attraction between polar molecules and non - polar molecules are not strong enough to mix. ### Second Question (What would happen if …
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how does water shape the earth? choose all that apply. □ by transportin…
- By transporting the products of weathering to other places. - By mechanically shaping rocks by flowing over or by frost wedging. - By dissolving minerals of rocks. - By directly…
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naming acids name the following acids. 1. hno₃ 2. hcl 3. h₂so₄ 4. h₂so₃…
1. Nitric acid 2. Hydrochloric acid 3. Sulfuric acid 4. Sulfurous acid 5. Acetic acid 6. Hydrobromic acid 7. Nitrous acid 8. Phosphoric acid 9. Hydrosulfuric acid 10. Carbonic aci…
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(1 point) co₂ nacl h₂o polar covalent ionic nonpolar covalent
\(CO_2\) - nonpolar covalent; \(NaCl\) - ionic; \(H_2O\) - polar covalent
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no₂⁻ nitrogen and oxygen have an electronegativity difference of △, so …
Electronegativity difference: \( 0.5 \); Bond type: polar covalent; Electron puller: oxygen (O); Oxygen charge: negative; Nitrogen charge: positive
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select the correct values to balance the equation: (1 point) 4nacl + 2s…
The coefficient of \( H_2O \) is 2, the coefficient of \( O_2 \) is 1, and the coefficient of \( Na_2SO_4 \) is 2. So the balanced equation is \( 4NaCl + 2SO_2 + 2H_2O + 1O_2 ight…
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use your knowledge of valence electrons and bond formation to complete …
The carbon atom shares \(\boldsymbol{\text{one pair of electrons}}\) (or "one electron pair") with each Hydrogen atom, forming \(\boldsymbol{\text{a single covalent bond}}\) (or "…
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use your knowledge of valence electrons and bond formation to complete …
1. The first dropdown (compound type): covalent molecule 2. The second dropdown (what carbon shares with each H): 1 electron (or "a pair of electrons" – but based on valence elect…
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use your knowledge of valence electrons and bond formation to complete …
First dropdown: Hydrogen Second dropdown: Methane Third dropdown: one pair of electrons Fourth dropdown: a single covalent bond
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use the reaction to answer the question. zn + 2hcl → zncl₂ + h₂ what ty…
C. replacement
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not all atoms can be bonded together at random and form stable configur…
- MgO (stable) - PH₃ (stable) - CaBr (unstable) - NaF₂ (unstable) So the stable molecules are MgO and PH₃. The checkboxes for MgO and PH₃ should be selected.
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use the equation below to answer the question: ch₄ + 2o₂ → co₂ + 2h₂o i…
There are now 4 molecules of \( H_2O \) (the first option: "There are now 4 molecules of \( H_2O \)")
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what is the balanced equation for the reaction of iron and oxygen gas s…
A. \(4\text{Fe} + 3\text{O}_2 \to 2\text{Fe}_2\text{O}_3\)
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which property of an atom is related to its ability to attract electron…
C. Electronegativity
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what is the correct coefficient for oxygen (o₂) to balance the followin…
6 (corresponding to the option with 6)
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the element bromine (br) has 7 valence electrons. which of the followin…
A. One atom of Lithium, which has one valence electron
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in a chemical reaction, if two elements have similar electronegativitie…
B. Covalent bond
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15) how many grams are in 4.5 moles of sodium fluoride, naf? 16) how ma…
Approximately 189 grams (or 188.96 g) ### Question 16: How many moles are in 98.3 grams of aluminum hydroxide, $\text{Al(OH)}_3$?
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select the correct answer what is one way that historians can establish…
A. by comparing the source to other established sources from that time period
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the temperature at 300 seconds (5 minutes) is the final temperature of …
25.0
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mass and the mole 1) how many moles are in 15 grams of lithium? 2) how …
Approximately \( 2.16 \) moles. ### Problem 2: How many grams are in 2.4 moles of sulfur?
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an element with mass 730 grams decays by 28.8% per minute. how much of …
22.0
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question 12 (5 points) which of these alcohols is often called wood alc…
C) Methanol ### Question 13
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a chemistry student in lab needs to fill a temperature - control tank w…
5.96 L
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a chemistry grad student measures the performance z of the new pump in …
$18.7$
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a chemistry grad student measures the performance z of the new pump in …
$9.4 \times 10^{-3}$
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please note: leaving this page before submitting your assessment will r…
a) True
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reconstructing a landscape which statements about this area are true ba…
- The area was once a forest. - The area was uplifted. - The area was probably covered by water.
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question 23 (1 point) which of the following is the electron configurat…
d) \(\frac{\uparrow\downarrow}{2s}\ \frac{\uparrow\downarrow}{2p}\ \frac{\uparrow}{}\ \frac{\uparrow}{}\)
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which of the following is the electron configuration for calcium, ca? a…
a) \(1s^22s^22p^63s^23p^64s^2\)
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question 21 (1 point) use the following information to answer the next …
d) -0.5 KCal
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question 20 (1 point) the amount of heat evolved or absorbed during che…
b) Changes in heats of reaction
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instructions for the following reaction, assume cucl₂ and agno₃ complet…
Question 4: 6 Question 5: 12
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3 numeric 1 point calculate, in kj, the $\\delta h_{rxn}$ for the follo…
$-908\ \text{kJ}$
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bond enthalpies (kj/mol) h–h 432; n–h 391; i–i 149; c=c 614 h–f 565; n–…
$\boldsymbol{-1304}$ kJ/mol
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1. formula 1 point $2\\ce{c6h14(l)} + 19\\ce{o2(g)} \ ightarrow 12\\ce{…
The energy change (released) is approximately $\boldsymbol{1980\ \text{kJ}}$ (or $\boldsymbol{-1980\ \text{kJ}}$ if sign denotes direction, negative for exothermic)
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the correct structure for 1 - methyl - 2,4,6 - trinitrobenzene(tnt) is …
b) The structure with a $\ce{CH_3}$ group and $\ce{NO_2}$ groups at positions corresponding to 1 - methyl - 2,4,6 - trinitrobenzene.
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question 15 (1 point) alkanes react with halogens in an addition reacti…
False
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question 14 (1 point) the compound above is classified as a(n) a) aldeh…
a) aldehyde
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question 13 (1 point) the correct iupac name for the compound above is …
b) 4 - ethoxypentanal
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question 12 (1 point) examine the figure below for the following questi…
b) B
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question 12 (1 point) examine the figure below for the following questi…
b) B
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question 10 (1 point) if the rate law for a hypothetical reaction is $r…
b) first