Answer:
B
Explanation:
Do diện tích tiếp xúc ở dạng bột cao hơn dạng tinh thể
Which of the following is true for the percentage yield of a reaction?
Answer:
It is always less than the theoretical yield.
When separating benzoic acid, naphthalene, and 3-nitroaniline, identify the solution used for each described purpose.
a. Extract reconstituted 3-nitroaniline out of the aqueous layer ___________
b. Extract benzoic acid into the aqueous layer _____________
c. Extract aniline into the aqueous layer ___________
d. Reconstitute aniline from aqueous layer__________
Answer:
a. Extract reconstituted 3-nitroaniline out of the aqueous layer: Dichloromethane.
b. Extract benzoic acid into the aqueous layer: 5% NaOH.
c. Extract aniline into the aqueous layer: 5% HCl.
d. Reconstitute aniline from aqueous layer: 6M NaOH.
Explanation:
Each of the answers is explained as follows:
a. Extract reconstituted 3-nitroaniline out of the aqueous layer: Dichloromethane.
Dichloromethane is an organochloride chemical and CH2Cl2 is its formula. It is commonly employed as a solvent since it is a colorless, volatile liquid with a sweet, chloroform-like odor. It is polar and miscible with numerous organic solvents, despite not being miscible with water.
b. Extract benzoic acid into the aqueous layer: 5% NaOH.
According to the Mass by Volume percentage concept, 5% NaOH solution (W/V) indicates 5g of NaOH dissolved in 100ml of water.
c. Extract aniline into the aqueous layer: 5% HCl.
Hydrochloric acid (HCl) is a common acid found in the human body as well as in laboratories, and it is a key component of stomach acid.
As a result, 5% HCl solution is made by mixing 8.26 mL concentrated HCl with roughly 50 mL distilled water, stirring well, and then adding water up to 100 mL.
d. Reconstitute aniline from aqueous layer: 6M NaOH.
6M NaOH refer to 6 moles in 1L MW (NaOH). Therefore, 6 moles of NaOH are dissolved in 1 liter of H2O to make a 6M NaOH solution. Because NaOH has a molar mass of 39.9997 g/mol, we'll need 240 g NaOH (39.997 x 6) in 1L of H2O to make a 6M solution.
Which one is the ionic compound?
Answer:
NAF IS AN IONIC COMPOUND
Explanation:
Answer:
Explanation:
CO2 is a covalent bonding. It is something from the middle of the periodic table bonded with something on the right of the periodic table. It is not ionic.
NH3 is also covalent. The H bonds with the N and the H has properties that resemble both the metals and non metals. That's why it is on both the left and right sides of the periodic table. In this case, it is more non metallic than metallic. Since Nitrogen is on the right side of the table, you have a situation where 2 nonmetals are bonding. It is not ionic.
The answer is NaF. Sodium is on the left side of the periodic table and F is on the right side. That's what it takes to get an ionic bond.
Rank each of the following gases in order of increasing Urms assuming equivalent amounts and all gases are at the same temperature and pressure where 1 is the lowest Urms Gas 1: H2S Gas 2: He Gas 3: NF3 Gas 4: H20
Answer:
NF3< H2S< H2O< He
Explanation:
The average speed of a gas depends on the relative molecular mass of the gas. Lighter gases have a greater average speed and move faster than heavier gases.
Hence, we need to arrange these gases listed in the question in order of decreasing molecular mass in order to obtain the order of increasing Urms assuming equivalent amounts and all gases are at the same temperature and pressure.
Hence; NF3< H2S< H2O< He
What is the definition of the molar mass of an element or compound?
Answer:
The molar mass is the mass of a given chemical element or chemical compound (g) divided by the amount of substance(mol) .
Explanation:
hope it may help you
mark as brainlist please
No tires P ni basura al suelo
Answer:
no halbo ingles
Explanation:
Which of the following aqueous solutions are good buffer systems?
a. 0.34 M calcium iodide + 0.22 M sodium iodide.
b. 0.27 M ammonia + 0.38 M ammonium nitrate.
c. 0.27 M nitric acid + 0.18 M sodium nitrate.
d. 0.18 M hydrofluoric acid + 0.14 M hydroiodic acid.
e. 0.14 M calcium hydroxide + 0.28 M calcium chloride.
Answer:
b. 0.27 M ammonia + 0.38 M ammonium nitrate.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to bear to mind the fact that buffest must be prepared by using either of the following pairs:
weak acid/conjugate base
weak base/conjugate acid
So that the pH might be set constant. In such a way, since a. shows two salts, c. a strong acid with a neutral base, d, shows two acids and e. a strong base with a neutral base, we infer the correct buffer is b. 0.27 M ammonia + 0.38 M ammonium nitrate because it has a weak base (ammonia) and its conjugate acid, ammonium.
Regards!
CAN SOMEONE HELP ME PLZ AND THANKS WILL MARK U AS BRAINLIEST
Explanation:
2. [tex]2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O[/tex]
First, we need to find the number of moles of [tex]CO_2[/tex] at 300K and 1.5 atm using the ideal gas law:
[tex]n= \dfrac{PV}{RT}= \dfrac{(1.5\:\text {atm})(33\:L)}{(0.082\:\text{L-atm/mol-K})(300K)}[/tex]
[tex]=2.0\:\text{mol}\:CO_2[/tex]
Now use the molar ratios to find the number of moles of ethane to produce this much [tex]CO_2[/tex].
[tex]2.0\:\text{mol}\:CO_2 \times \left(\dfrac{2\:\text{mol}\:C_2H_6}{4\:\text{mol}\:CO_2}\right)[/tex]
[tex]=1.0\:\text{mol}\:C_2H_6[/tex]
Finally, convert this amount to grams using its molar mass:
[tex]1.0\:\text {mol}\:C_2H_6 \times \left(\dfrac{30.07\:\text g\:C_2H_6}{1\:\text{mol}\:C_2H_6} \right)[/tex]
[tex]=30.1\:g\:C_2H_6[/tex]
3. [tex]3Zn + 2H_3PO_4 \rightarrow 3H_2 + Zn_3(PO_4)_2[/tex]
Convert 75 g Zn into moles:
[tex]75\:\text g\:Zn \times \left(\dfrac{65.38\:\text g\:Zn}{1\:\text{mol}\:Zn}\right)=1.1\:\text{mol}\:Zn[/tex]
Then use the molar ratios to find the amount of H2 produced.
[tex]1.1\:\text{mol}\:Zn \times \left(\dfrac{3\:\text{mol}\:H_2}{3\:\text{mol}\:Zn}\right)=1.1\:\text{mol}\:H_2[/tex]
Now use the ideal gas law [tex]PV=nRT[/tex] to find the volume of H2 produced at 23°C and 4 atm:
[tex]V= \dfrac{nRT}{P}= \dfrac{(1.1\:\text{mol}\:H_2)(0.082\:\text{L-atm/mol-K})(296K)}{4\:\text{atm}}[/tex]
[tex]=8.9\:\text L\:H_2[/tex]
Write briefly on carbohydrates
Answer:
carbohydrates are simple sugars which can be broken down to form 3 sugars.
which are , (maltose) (fructose) & (glucose)
Sodium is a highly reactive metal and
chlorine is a toxic gas, but when they
come together the resulting material,
sodium chloride, is essential for life.
Which of the following is true when
sodium and chlorine are brought into
contact with one another?
Answer:
NaCl
Explanation:
[tex]na + cl > nacl[/tex]
This is also a salt
How many atoms are in 7.0 g of Ne?
Answer:
2.11×10²³ atoms.
Explanation:
From the question given above, the following data were obtained:
Mass of Ne = 7 g
Number of atoms =?
Recall:
1 mole of Ne = 6.02×10²³ atoms
1 mole of Ne = 20 g
Thus,
20 g of Ne = 6.02×10²³ atoms
Finally, we shall determine the number of atoms in 7 g of Ne. This can be obtained as follow:
20 g of Ne = 6.02×10²³ atoms
Therefore,
7 g of Ne = (7 × 6.02×10²³) / 20
7 g of Ne = 2.11×10²³ atoms
Thus, 7 g of Ne contains 2.11×10²³ atoms.
Which is a general chemical equation for an exothermic, single-replacement reaction?
A.
AB + CD + energy → AD + CB
B.
AB + C → A + CB + energy
C.
AB + CD → AD + CB + energy
D.
AB + C + energy → A + CB
Answer:
c
Explanation:
it is because the chemical reaction will have the exposure to all the minerals with Microsoft word
Compound EX4 reacts with Y2 giving two products: EX Y and XY. Calculate the E- X bond enthalpy if the reaction liberates 243.6 kJ/mol and other bond enthalpies are:
Y-Y 109 kJ/mol,
X-Y 123.1 kJ/mol and
E-Y 290 kJ/mol.
a. 547.7 kJ/mol
b. 60.5 kJ/mol
c. 234.7 kJ/mol
d. 20.6 kJ/mol
e. 176.9 kJ/mol
Answer:
Option B
Explanation:
From the question we are told that:
Equation
[tex]EX_4+Y_2->EX_3Y+XY[/tex]
Bond enthalpies are:
[tex]Y-Y 109 kJ/mol,[/tex]
[tex]X-Y 123.1 kJ/mol[/tex]
[tex]E-Y 290 kJ/mol.[/tex]
Generally the equation for the energy used to break E-X and Y-Y is mathematically given by
[tex]E_2=109+x[/tex]
Therefore
Total Energy Liberated is
[tex]E_T=E_1+E_2[/tex]
[tex]E_T=413.1+109+x[/tex]
[tex]E_T=304.1-x[/tex]
Since
[tex]E_T+E_I[/tex]
Therefore
[tex]304.1-x=243.6[/tex]
[tex]x=60.5kJ/mol[/tex]
Option B
What is Sublimation?-.-
Explanation:
Sublimation is the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage
which of the following molecules would you expect to have a dipole moment of zero? a,CH2 Ch3
bH2C=0
cCH2cl
dNH3
Answer: The molecule [tex]CH_{3}-CH_{3}[/tex] is expected to have a dipole moment of zero.
Explanation:
The product of magnitude of the charge calculated in electrostatic units is called dipole moment.
Formula for dipole moment is as follows.
Dipole moment = Charge (in esu) [tex]\times[/tex] distance (in cm)
Non-polar molecules have zero dipole moment.
For example, [tex]CH_{3}-CH_{3}[/tex] is a non-polar molecule so its dipole moment is zero.
[tex]H_{2}C=O[/tex] is a polar molecule so it will have dipole moment.
[tex]CH_{2}Cl_{2}[/tex] is a polar molecule so it will have dipole moment.
[tex]NH_{3}[/tex] has nitrogen atom as more electronegative than hydrogen atom. So, net dipole moment will be in the direction of nitrogen atom.
Thus, we can conclude that the molecule [tex]CH_{3}-CH_{3}[/tex] is expected to have a dipole moment of zero.
For this task, you will consider the information you have researched so far, conduct further research, create a thesis, and write a one-page research paper based on your research and thesis. Your research and thesis should address the following prompt: How should Florida address its growing energy demands, and what energy sources should the state focus on in the future? Consider the energy options available in Florida, the pros and cons of various energy sources, as well as concepts such as energy conservation.
In the next steps, you will conduct further research, form a thesis, and write a one-page research paper based on your findings and opinions.
a. Select a topic. Before creating your report, understand the purpose, process, and goals of a research assignment.
The first step in writing a research paper is to select a topic; in this assignment your topic should focus on issues related to energy production and consumption in Florida.
Begin brainstorming ideas by thinking about your prior knowledge of the topic.
Try engaging in preliminary research to help select a relevant, interesting topic.
b. Choose a thesis statement. Begin thinking about the stance or viewpoint that your writing will take. Once you have a general idea of your opinion, develop a thesis statement, or the main idea of an essay that includes the topic and the viewpoint.
Make sure that the thesis is relevant to the topic and assignment.
Keep in mind that as you continue researching and begin writing, your thesis may change slightly from your original idea.
Check with your teacher to make sure that the topic you chose is appropriate and feasible.
c. Gather sources. Next, begin gathering and organizing additional sources to build your argument. It is important to understand the purpose of your research. Evaluate each source, and consider these questions:
Who authored the document?
What is the purpose of the document?
When was the document written?
How will this document help your argument?
d. Develop your position. Now that you have analyzed sources to use as evidence, revisit the essay topic. Then develop your report with these factors in mind:
Create an outline to help organize the structure of your report.
Your thesis should be well-supported by your research.
Match the evidence in your sources to the points in your report.
Articulate any solutions you may think are relevant to deal with the energy issues in Florida.
e. Write your first draft. Write a one-page research paper on your selected topic. As you write your paper, use quotations from and summaries of your sources to support your argument.
To avoid plagiarism, make sure to cite your sources properly with in-text citations and a works cited page.
f. Proofread and Revise. When you are finished writing your first draft, reread your essay to check for all of the points above, and then proofread and revise to be sure your work doesn’t contain errors in grammar, spelling, logic, or cohesion. Finally, develop a final draft that is polished and ready to be turned in. Nice work!
Answer:
What kind of chemical reaction occurs when fossil fuels and biomass are burned? What is produced in addition to energy?
What is acid rain? Which fossil fuel causes acid rain? What are the chemical reactions that produce the acid?
Difference Between Biomass and Fossil Fuels
In terms of environmental impact, what’s the difference between natural gas, coal, and biomass? Consider both carbon dioxide (CO2) emissions and acid rain.
What’s the difference between nonrenewable and renewable energy sources? Is biomass a renewable energy source?
What’s a new discovery that makes it easier to use biomass as an energy source?
Comparing Biomass with Other Renewable Energy Sources
What are the pros and cons of several renewable energy sources? Renewable energy sources include biomass, wind power, hydropower, solar power, and geothermal power.
Making Recommendations for Energy Choices
Which renewable energy sources should be developed in your area, and why? Consider abundance of the energy source, ease of setup in your area, and cost.
Review the seven questions. Write a few sentences summarizing what you already know about these topics.
Explanation:
The specific heat capacity of liquid water is 4.18 J/g-K. How many joules of heat are needed to raise the temperature of 6.00 g of water from 36.0°C to 75.0 °C?
Answer:
978 J
General Formulas and Concepts:
Thermodynamics
Specific Heat Formula: q = mcΔT
q is heat (in J) m is mass (in g) c is specific heat (in J/g °C) ΔT is change in temperature (in °C)Explanation:
Step 1: Define
[Given] c = 4.18 J/g K
[Given] m = 6.00 g
[Given] ΔT = 75.0 °C - 36.0 °C = 39.0 °C
[Solve] q
Step 2: Find q
Substitute in variables [Specific Heat Formula]: q = (6.00 g)(4.18 J/g K)(39.0 °C)Multiply [Cancel out units]: q = 978.12 JStep 3: Check
Follow sig fig rules and round. We are given 3 sig figs.
978.12 J ≈ 978 J
Answer:
I don't remember this topic very well.
Explanation:
if we want to increase 1C° of 1 gram water. we must use 4.18 joules energy that 75-36= 39 C° for 6 gram H2O we should use 6*39*(4.18) joules
3 The questions refer to the substances in the table.
Melting point/°C
Boiling point/°C
A
-259
-253
B
0
100
C
3700 (sublimes)
D
-116
34.5
E
801
1413
a Write down the physical states of each compound at
i 30°C.
ii -100°C
iii 80°C
Explanation:
3 The questions refer to the substances in the table.
Melting point/°C
Boiling point/°C
A
-259
-253
complete and balanced the following equations by predicting the products of each reaction pair.
NA + LiCI -> _ + _
Explanation:
this is a single Replacement Reaction, so Na and Cl will form a bond.
Compound A, C8H10, absorbed 3 equivalents of H2 on catalytic hydrogenation over a Pd/C catalyst to give B (C8H16). On ozonolysis, compound A gave, among other things, a ketone which was identified as cyclopentanone. On treatment with NaNH2 in NH3, followed by addition of iodomethane, compound A gave a new hydrocarbon, C (C9H12). Draw the structure of Compound A and Compound B.
Answer:
Compound A, C8H10, absorbed 3 equivalents of H2 on catalytic hydrogenation over a Pd/C catalyst to give B (C8H16). On ozonolysis, compound A gave, among other things, a ketone which was identified as cyclopentanone. On treatment with NaNH2 in NH3, followed by addition of iodomethane, compound A gave a new hydrocarbon, C (C9H12). Draw the structure of Compound A and Compound B.
Explanation:
The degree of unsaturation in the given compound A C8H10 is:
DU= (Cn+1)-Hn/2 -Xn/2 +Nn/2
DU=(8+1)-10/2
=9-5
=4
So, the given compound has either three double bonds and a ring or four double bonds or four rings.
Given,
compound A C8H10 absorbed three equivalents of H2 on catalytic hydrogenation that means compound A has three double bonds or it has one double bond and one triple bond.
The structure of compounds A, B and C along with the entire reaction is shown below:
What is the IUPAC name for this organic molecule?
Answer:
2–methylbutane
Explanation:
To name the compound given above, the following must be obtained:
1. Determine the longest continuous carbon chain. This gives the parent name of the compound.
2. Determine the substituent group attached.
3. Determine the position of the substituent group by giving it the lowest possible count..
4. Combine the above to obtain the name of the compound.
With the above information, we can name the compound as follow:
1. The longest continuous carbon chain of the compound is 4. Thus, the parent name is butane.
2. The substituent group attached to the compound is methyl (–CH₃).
3. The methyl (–CH₃) group is located at carbon 2 (i.e counting from the left side).
4. The name of the compound is:
2–methylbutane
Select the correct answer.
What is the solution to the problem expressed to the correct number of significant figures?
(102,900 ÷ 12) + (170 × 1.27) = ?
Consider an atom that has an electron in an excited state. The electron falls to a lower energy level. What effect does that have on the electron?
A.The electron releases energy in the form of light.
B.The electron absorbs energy in the form of light.
C.The electron retains its energy without any change.
D.The electron transfers its energy to other electrons.
Answer:
c it does not change the energy state
Explanation:
The most stable conformation of the following compound has
A. An axial methyl group and an axial ethyl group.
B. An axial methyl group and an equatorial ethyl group.
C. An axial tert-butyl group.
D. An equatorial methyl group and an equatorial ethyl group.
E. An equatorial methyl group and an axial ethyl group.
Answer:
The most stable conformation of the following compound has
A. An axial methyl group and an axial ethyl group.
B. An axial methyl group and an equatorial ethyl group.
C. An axial tert-butyl group.
D. An equatorial methyl group and an equatorial ethyl group.
E. An equatorial methyl group and an axial ethyl group.
Explanation:
The most stable conformation in the cyclohexane ring is the one in which both the substituents are in the equatorial position.
Among the given options,
option D An equatorial methyl group and an equatorial ethyl group.
When the substituents in the cyclohexane ring are in equatorial positions then, the steric repulsions will be reduced.
Answer is option D.
A student dissolves 7.9 g of stilbene (C14H12) in 475. mL of a solvent with a density of 1.03 g/mL. The student notices that the volume of the solvent does not change when the stilbene dissolves in it. Calculate the molarity and morality of the students solution. Round both of your answers to 2 significant digits.
Answer:
Molarity: 0.092M
Molality: 0.090m
Explanation:
Molarity, M, is defined as the moles of solute (In this case, C14H12 -Molar mass: 180.25g/mol-) in 1L of solution.
The molality, m, are moles of solute per kg of solvent.
Molarity:
Moles solute:
7.9g * (1mol/180.25g) = 0.04383 moles
Liters solution:
475mL = 0.475L
Molarity: 0.04383 moles / 0.475L = 0.092M
Molality:
kg solvent:
475mL * (1.03g/mL) = 489.25g = 0.48925kg
Molality:
0.04383 moles / 0.48925kg = 0.090m
PLZZZ HELPPPPPPPPPPPPPPPP
The general formula for ____________ and ____________ are CnH2n+2 and CnH2n , respectively. Axial and equatorial hydrogen atoms are interconverted during a ____________ . The anti conformation is ____________ in energy than a gauche conformation. The increase in energy when tetrahedral bond angles deviate from the optimum angle of 109.5° is known as ____________ strain. The ____________ position has more room than the ____________ position, so larger substituents are more stable in the equatorial position.
Answer:
Alkanes
Cycloalkanes
Ring flip
Lower
Angle
Equatorial
Axial
Explanation:
For alkanes, the general molecular formula is CnH2n+2 while for cycloalkanes, the general molecular formula is CnH2n.
The cycloalkanes could undergo a ring flip in which axial and equatorial hydrogen atoms are interconverted.
The lower energy conformation of alkanes is the anti conformation and not the gauche conformation due to steric strain.
When the bond angle in alkanes deviate from the ideal 109.5°, an angle strain has occurred.
For bulky groups, the equatorial position his preferred since it has more room than the axial position.
What is the volume in (a) liters and (b) cubic yards of a room that is 10. meters wide by 15 meters long and 8.0 ft high?
Answer:
V = 364500 L, 476.748 yard³
Explanation:
Given that,
The dimensions of a room are 10 meters wide by 15 meters long and 8.0 ft high.
l = 10 m, b = 15 m, h = 8 ft = 2.43 m
The volume of the room is :
V = lbh
So,
V = 10×15×2.43
V = 364.5 m³
As 1 m³ = 1000 L
364.5 m³ = 364500 L
Also, 1 m³ = 1.30795 yard³
364.5 m³ = 476.748 yard³
Hence, this is the required solution.
Draw the product formed when diene and dienophile react in a Diels–Alder reaction.
Answer:
Explanation:
Diels-Alder reactions are cyclo-additional reactions between conjugated dienes and a dienophile (a substituted alkene compound for example acrylic acid) to produce a ring structure of cyclohexene compounds.
From the image attached below, we will see the reaction between 2,3-dimethylbuta-1,3-diene which is a conjugated diene with acrylic acid to produce a Diel-Alder adduct as the product. From the reaction, a single new π-bond and two σ-bonds are produced.
Identify the bronsted-lowry acid and the bronsted-lowry base in this reaction on the left side of each of the following equations, and also identify the conjugate acid and conjugate base of each on the right side.
mathrm { NH } _ { 4 } ^ { + } ( a q ) + mathrm { CN } ^ { - } ( a q ) rightleftharpoons mathrm { HCN } ( a q ) + mathrm { NH } _ { 3 } ( a q )
Answer: [tex]NH_4^+[/tex] is an acid, [tex]CN^-[/tex] is a base, [tex]NH_3[/tex] is conjugate base and [tex]HCN[/tex] is conjugate acid
Explanation:
According to Bronsted and Lowry's theory:
An acid is defined as a proton donor while a base is defined as a proton acceptor.
In a chemical reaction, an acid loses a proton to form a conjugate base while a base accepts a proton to form conjugate acid.
For the given chemical reaction:
[tex]NH_4^+(aq)+CN^-(aq)\rightleftharpoons HCN(aq)+NH_3(aq)[/tex]
[tex]NH_4^+[/tex] is losing a proton thus it is an acid to form [tex]NH_3[/tex] which is its conjugate base
[tex]CN^-[/tex] is gaining a proton thus it is a base to form [tex]HCN[/tex] which is its conjugate acid
Hence, [tex]NH_4^+[/tex] is an acid, [tex]CN^-[/tex] is a base, [tex]NH_3[/tex] is conjugate base and [tex]HCN[/tex] is conjugate acid