PRACTICE PROBLEM Two compounds, A and B, have the same molecular formula, C6H8. Both A and B react with two molar equivalents of hydrogen in the presence of platinum to yield cyclohexane. Compound A shows three signals in its broadband decoupled NMR spectrum. Compound B shows only two NMR signals. Compound A shows an absorption maximum at 256 nm, whereas B shows no absorption maximum at wavelengths longer than 200 nm. What are the structures of A and B
Answers
Answer:
See explanation
Explanation:
One basic thing that we must keep in mind is that A and B are both dienes.
The NMR spectrum and absorption maxima of A and B indicates that A may be a conjugated diene while B may be an isolated diene.
Remember that conjugated dienes shift the absorption maxima to longer wavelengths due to π - π* transition.
The two structures attached may suffice for compounds A and B
Related Questions
A student measured the masses of four different-sized blocks. The student determined that each block had a mass of 50 grams.
(There is a small block, a little bit bigger block, a big block and the biggles block)
Which block has the least density?
Answers
Answer:..
Explanation:
if u trust urself do it
Study these images.
4 photos of clouds. 1: Sky covered with large, flat layers of blue, grey clouds. 2: A tall, fluffy cloud shaped like an anvil. 3: Round, puffy clouds in a blue sky. 4: Thin, wispy clouds high in the sky.
Which image shows a cumulonimbus cloud?
1
2
3
Answers
Answer:
3
Explanation:
I wish you the best, its three or 2
Answer:
2
Explanation:
Edge 2021
Nicotinic acid, HC6H4NO2, is a B vitamin. It is also a weak acid with Ka = 1.4 × 10-5. Calculate [H+] and the pH of a 0.041 M solution of HC6H4NO2.
Answers
Answer:
[H+] = 7.576x10⁻⁴M
pH = 3.12
Explanation:
Based on the equilibrium of the nicotinic acid in water:
HC6H4NO2(aq) + H2O(l) ⇄ C6H4NO2-(aq) + H3O+(aq)
Ka = [C6H4NO2-] [H3O+] / [HC6H4NO2]
As both C6H4NO2-(aq) and H3O+(aq) comes from the same equilibrium, we can approximate their concentration as X and replace:
Ka = [C6H4NO2-] [H3O+] / [HC6H4NO2]
1.4x10⁻⁵ = [X] [X] / [0.041M]
5.47x10⁻⁷ = X²
7.576x10⁻⁴M = X = [H+]And as pH is defined as -log [H⁺]
pH = 3.12There are exaclty 640 acres in one square mile. How many square meters are in 2.2 acres?
Answers
Answer:
8,903.09 square meters
Explanation:
Doing a quick search online we can see that there are exactly 4046.86 square meters in a single acre (1 acre). Therefore, we can simply use the rule of three to calculate the total amount of square meters in 2.2 acres. We do this by multiplying 2.2 acres by 4046.86 square meters and then dividing by 1 acre to solve for x.
1 acre <=====> 4046.86 square meters
2.2 acres <====> x
(2.2 * 4046.86) / 1 = x
8903.09 / 1 = x
8,903.09 = x
Finally, we can see that there are 8,903.09 square meters in 2.2 acres.
2 2 6 2 6 2 10 3
1s 2s 2p 3s 3p 4s 3d 4p
=
Answers
Answer:
ARSENIC
Explanation:
It has an atomic number of 33
The system is originally at equilibrium with [butane] = 1.0 M and [isobutane] = 2.5 M.If 0.50 mol/L of isobutane is suddenly added and the system shifts to a new equilibrium position, what is the equilibrium concentration of butane?
Answers
Answer:
1.14 M
Explanation:
Let's consider the following reaction.
butane ⇄ isobutane
We can use the concentrations at equilibrium to calculate the equilibrium constant.
Kc = [isobutane] / [butane]
Kc = 2.5 / 1.0
Kc = 2.5
If we add 0.50 M of isobutane, we get [isobutane] = 2.5 + 0.50 = 3.0 M.
This will be an initial concentration in an ICE chart.
butane ⇄ isobutane
I 1.0 3.0
C +x -x
E 1.0+x 3.0-x
The equilibrium constant is:
Kc = 2.5 = [isobutane] / [butane]
2.5 = (3.0-x) / (1.0+x)
2.5 + 2.5x = 3.0-x
x = 0.14
The equilibrium concentration of butane is:
[butane] = 1.0+x = 1.14 M
What happen when a piece of sodium is exposed in air?
Answers
Answer:
I literally got this from google.
Explanation:
In ordinary air, sodium metal reacts to form a sodium hydroxide film, which can rapidly absorb carbon dioxide from the air, forming sodium bicarbonate. ... In a comparatively dry atmosphere, sodium burns quietly, giving off a dense white caustic smoke, which can cause choking and coughing.
Happy almost Halloween! :)
Writing key words in the margin is part of which note-taking procedure?
Select one:
a. record
b. review
c. reduce
d. recite
Answers
Which statement explains why NaBr is classified as a compound?
1.
Na and Br are chemically combined in a fixed proportion.
2.
Na and Br are both nonmetals.
3
NaBr is a solid
298 Kand standard pressure.
4.
NaBr dissolves in H20 at 298 K.
Submit
Hide Toolbar
Answers
Answer:1
Explanation:i know cuz I got it right
NaBr is classified as a compound because sodium and bromine are chemically combined in a fixed proportion.
Explanation:
Element is defined as the simplest form of a substance that cannot be divided further by any physical means.For example oxygen ([tex]O_2[/tex]), coal (carbon) etc.A compound is defined as the form of a substance in which two or more different elements are chemically combined together in a fixed proportion.For example sodium chloride (NaCl), nitric acid ([tex]HNO_3[/tex])A compound can be further divided into a simple substance.So, from this, we can conclude that NaBr is classified as a compound because sodium and bromine are chemically combined in a fixed proportion.
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A solution is made by mixing of 42.g water and 77.g of acetic acid HCH3CO2. Calculate the mole fraction of water in this solution.
Answers
Moles of [tex]H_2O[/tex] ,
[tex]n_{H_2O}=\dfrac{42}{2\times 1 + 16}=\dfrac{42}{18}\\\\n_{H_2O}=2.33\ moles[/tex]
Moles of acetic acid [tex]HCH_3CO_2[/tex] ,
[tex]n_{A.A}=\dfrac{77}{1 + 12 + 3 + 12 + 16\times 2}=\dfrac{77}{60}\\\\n_{A.A}=1.28\ moles[/tex]
Mole fraction of water :
[tex]M.F_{H_2O}=\dfrac{n_{H_2O}}{n_{H_2O}+n_{A.A}}\\\\M.F_{H_2O}=\dfrac{2.33}{2.33+1.28}\\\\M.F_{H_2O}=0.645[/tex]
Therefore, mole fraction of water in this solution is 0.645 .
Hence, this is the required solution.
3. A certain Chemical Industry company has a quality control job opening. The job is open for any major with basic knowledge of chemistry. You decided to apply. In the interview the HR personnel gives you a sealed folder from a certain lot to test your laboratory experience, as well as your quantitative and volumetric analysis skills. The chemical contained in the sample is benzoic acid (C-H602) and it is known to be a monoprotic acid. In order to get the job, you need to determine if the sample's purity is acceptable based on their standards. Inside the folder you found a vial with a solid sample labeled BA-I, a periodic table, and the following data: 1.250 g of the sample required 20.15 mL of 0.500 M concentration of NaOH to reach the end point. The lot can be denied if the purity is below 99.5 % purity.
1) What is the purity in the sample?
2) Is it the purity acceptable?
3) Would you repeat the titration experiment?
Answers
Answer:
1) 97.6%
2) No the purity is not acceptable because the standard is 99.5% purity.
3) Yes I will repeat the titration experiment to confirm my result.
Explanation:
Equation of the reaction;
C7H6O2(aq) + NaOH(aq) ---------> C7H5ONa(aq) + H2O(aq)
From the information provided;
Number of moles of NaOH reacted = concentration × volume = 20.15/1000 × 0.500 = 0.01 moles
From the reaction equation;
1 mole of C7H6O2 reacts with 1 mole of NaOH
Hence 0.01 moles of C7H6O2 will react with 0.01 moles of NaOH
Mass of C7H6O2 reacted = number of moles of C7H6O2 × molar mass of C7H6O2
Molar mass of C7H6O2 = 122.12 g/mol
Mass of C7H6O2 reacted = 0.01 moles × 122.12 g/mol = 1.22 g
Percentage by mass of pure C7H6O2 in the impure sample = 1.22/1.250 × 100 = 97.6 %
Describe three factors that could limit the growth of the prairie dog population
Answers
Answer:
Changes in environment, food source changes and disease?
Explanation:
I dont know what the answer choices are
Answer:
changes in the environment
Explanation:
like digging big holes.
Hope this helps!
The half life of oxygen is 2 minutes. What fraction of a sample of 0.15 will remain after 5 half lives?
Answers
Answer:
3.13%.
Explanation:
The following data were obtained from the question:
Original amount (N₀) = 0.15
Half life (t½) = 2 mins
Number of half-life (n) = 5
Fraction of sample remaining =.?
Next, we shall determine the amount remaining (N) after 5 half-life. This can be obtained as follow:
Amount remaining (N) = 1/2ⁿ × original amount (N₀)
NOTE: n is the number of half-life.
N = 1/2ⁿ × N₀
N = 1/2⁵ × 0.15
N = 1/32 × 0.15
N = 0.15/32
N = 4.69×10¯³
Therefore, 4.69×10¯³ is remaining after 5 half-life.
Finally, we shall the fraction of the sample remaining after 5 half-life as follow:
Original amount (N₀) = 0.15
Amount remaining (N) = 4.69×10¯³
Fraction remaining = N/N₀ × 100
Fraction remaining = 4.69×10¯³/0.15 × 100
Fraction remaining = 3.13%
Question 1 of 10
What is technology?
A. An understanding of something new.
B. The steps that engineers go through to create a product.
C. Something created using science for use by society.
D. A method that is used to solve problems,
SUBMIT
Answers
Answer:
C.
Explanation:
You can use the series of elimination for this. First, you look at A. Technology is not an understanding of something new, so we cross that out. Second, you look at B. Technology isn't a series of steps, so we can mark that one off. Third, you look at C. Technology is something created using science for use by society, so we can keep that in mind. Lastly, we check D. Technology doesn't match up to the definition, so we can cross that one out. The answer that would make the most sense would be D.
Which graph best matches a person walking away at a constant speed
Answers
what is the first step in the scientific inquiry process
Answers
Answer:
make an observation that describes a problem
Explanation:
Answer:
The first step in the Scientific Method is to make objective observations.
Explanation:
....-
The potential energy of a roller coaster is 50 joules. The kinetic energy of the same coaster is 50 joules. What is the mechanical energy of the coaster? O joules 50 joules 100 joules
Answers
Answer:
100 joules
Explanation:
The mechanical energy (M.E) of an object describes the objects ability to do work. The mechanical energy encompasses the object's energy due to its position (potential energy) and its energy due to motion (kinetic energy).
Therefore,
M.E = K.E + P.E
According to this question, potential energy (P.E) of the roller coaster is 50J and the kinetic energy (K.E) is also 50J. Hence, the mechanical energy (M.E) is
M.E = 50J + 50J
M.E = 100J
If the P.E and K.E of a roller coaster is 50 Joules respectively, the mechanical energy of the roller coaster is 100 Joules.
Given the following data:
Potential energy of roller coaster = 50 Joules.Kinetic energy of roller coaster = 50 Joules.To find the mechanical energy of the roller coaster:
The mechanical energy of a physical object or body is the total sum of the potential energy (P.E) and kinetic energy (K.E) possessed by an object.
Mathematically, mechanical energy is given by the formula;
Substituting the given parameters into the formula, we have;
[tex]M.E = 50 + 50[/tex]
Mechanical energy (M.E) = 100 Joules.
Therefore, the mechanical energy of the roller coaster is 100 Joules.
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In science class, a student is given a copper cylinder to investigate. The student measures the mass of the cylinder as 53.76 grams. The
student measures the volume of the copper as 6 cm. Which additional property of the copper can the student determine from these
measure
Answers
Answer:
From these two values, i.e. mass and volume, density of the copper cylinder can be calculated.
Formula of density is :
Density = Mass / volume.
Now we have mass: 53.76g and volume 6cm³
Density = 53.76 / 6
Density= 8.96 g/cm³
What do scientists call all of the compounds that contain carbon and are found in living things?
organic
inorganic
acidic
nonacidic
Answers
Answer:
Organic
Explanation:
Edge student
How does the temperature of the core compare to the Sun?
The core is colder the surface of the Sun.
o The Sun is hotter than the core.
The core may be as hot as the surface of the Sun.
The core is hot during the day but cooler at nighttime.
Answers
the isotopes of an elements have the same masse
Answers
Answer:
True
Explanation:
But have different neutrons
In the KHP titration, imagine a student fills his buret with NaOH solution imediately after rinsing it with water and after reading the initial volume, begins the titration. He skips the step in which the buret is rinsed with a small amount of the NaOH. How is this oversight likely to reflect in his calculation of the molarity of the NaOH? Explain your reasoning in detail.
Answers
Answer:
Explanation:
Since the student fills up the buret with NaOH without rinsing it with small amount of NaOH , the water that is remaining stuck with the walls of the buret will dilute the solution of NaOH and it will result in lowering the morality of the solution . The molar concentration of the NaOH will no longer remain the same . It will lead to wrong calculation and hence wrong result.
The washing of burette in titration with NaOH solution results in the maintaining the concentration of the NaOH in the solution and allows the correct calculation of the molarity.
What is titration?The titration has been the reaction of the acid with the base resulted in the formation of salt and water and had the neutralization reaction.
The molarity of the base has been used in the analysis of the acid concentration on the neutralization reaction.
The skipping of the step of washing with NaOH resulted in the altering in the concentration of the NaOH with the stuck water on the walls of the burette, and thereby resulted in wrong calculation.
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(a) Write a briefexperimental procedure for the chromic acid test.Include all observations such ascolor change, precipitation, etc.(5 points)(b) What functional groups can be distinguished by this test?(2points)(c) What is the reason for the color change if you get a positive chromic acid test?(3points)(d) Sketch a reaction mechanism for a positive chromic acid test with the above given molecules.(10points) g
Answers
Answer:
See explanation
Explanation:
a) -About 1-2 drops of the unknown is dissolved in approximately 1 mL of analytical grade acetone standard solution. The test solution is added and shaken thoroughly. If a positive test is not immediately observed, the set should be allowed to stand for 1-2 minutes. A positive result means the appearance of a green color.
b) The functional groups that can be distinguished by the test are alcohols and aldehydes.
Aldehydes give a positive test to chromic acid but ketones do not.
Primary and secondary alcohols give a positive test to chromic acid but tertiary alcohols do not.
c) Chromic Acid Test involves Cr in the +6 oxidation state. A positive test implies the reduction of orange Cr^6+ to green chromium Cr^3+.
d) The compounds were not shown but this image attached from lumen learning summarizes the reaction mechanism of chromic acid test.
The solubility of limestone, CaCO3, at 25˚C is 0.00067 g/100 mL. Write the chemical equation for the solubility equilibrium of this sparingly soluble salt in water. Then compute the molar solubility and the solubility product constant Ksp for CaCO3 at 25˚C.
Answers
Answer:
4.5 × 10⁻⁹
Explanation:
Step 1: Write the reaction for the solution of CaCO₃
CaCO₃(s) ⇄ Ca²⁺(aq) + CO₃²⁻(aq)
Step 2: Convert the solubility of CaCO₃ from g/L to mol/L
We will use the following conversion factors:
The molar mass of CaCO₃ is 100.09 g/mol.1 L= 1000 mL.There are 0.00067 g of CaCO₃ per 100 mL of solution.[tex]\frac{0.00067 gCaCO_3}{100mLSol} \times \frac{1molCaCO_3}{100.09gCaCO_3} \times \frac{1000mLSol}{1LSol} = 6.7 \times 10^{-5} M[/tex]
Step 3: Calculate the solubility product constant (Ksp)
To relate Ksp and the molar solubility (S), we need to make an ICE chart.
CaCO₃(s) ⇄ Ca²⁺(aq) + CO₃²⁻(aq)
I 0 0
C +S +S
E S S
The solubility product constant is:
Ksp = [Ca²⁺].[CO₃²⁻] = S² = (6.7 × 10⁻⁵)² = 4.5 × 10⁻⁹
Copying is not allowed. You must show all work in order to receive credit. Naturally occurring silver has two isotopes. Isotope A has a relative mass of 106.9051 and an abundance of 51.82%. Isotope B has a relative mass of 108.9047. Calculate the atomic mass of silver from these data.
Answers
Answer: The atomic mass of silver is 107.8
Explanation:
Average atomic mass is the average mass of all the isotopes present depending on the relative abundance of each isotope.
Mass of isotope A = 106.9051
% abundance of isotope 1 = 51.82% = [tex]\frac{51.82}{100}[/tex]
Mass of isotope B = 108.9047
% abundance of isotope 2 = (100-51.82)% = [tex]\frac{48.18}{100}[/tex]
Formula used for average atomic mass of an element :
[tex]A=\sum[(106.9051)\times \frac{51.82}{100})+(108.9047)\times \frac{48.18}{100}]][/tex]
[tex]A=107.8[/tex]
Therefore, the average atomic mass of silver is 107.8
Quickly please! Which is a group of tissues that work together to carry out a common function?
cell
organ
organelle
organ system
Answers
Answer:
organ system
Explanation:
Answer:
B) organ
Explanation:
4. Horizontal rows of the Periodic Table are called:
a, Clusters
Groups
b. Families
d) Periods
Answers
The pressure caused by a sample of gas is 2.25 atm. 1 atm is
equal to 1.01 kPa. What is the pressure in Newton per square
centimeter?
Answers
Answer:
[tex]0.326\frac{N}{cm^2}[/tex]
Explanation:
Hello.
In this case, considering that 1 atm equals 1.01 kPa, we can compute the pressure in kPa first as shown below:
[tex]2.25atm*\frac{1.01kPa}{1atm} =3.26kPa[/tex]
Now, we convert kPa to Pa, considering 1 kPa equals 1000 Pa:
[tex]3.26kPa*\frac{1000Pa}{1kPa}=3260Pa[/tex]
Now, since Pa is equal to N/m², and 1 m equals 100 cm, the pressure in newton per square centimeter turns out:
[tex]3260\frac{N}{m^2}*(\frac{1m}{100cm})^2 \\\\0.326\frac{N}{cm^2}[/tex]
Best regards.
Identify the following reaction as an endothermic reaction, exothermic reaction, or both endothermic and exothermic:
Dissolving NH4Cl in water to make a cold pack.
Answers
Answer:
Endothermic reaction
Explanation:
Endothermic reactions are defined as the type of chemical reaction in which the system absorbs the energy from the surroundings and the temperature of the surrounding decreases while in Exothermic reactions, heat is released by the system to the surroundings and it makes the surrounding warm.
The given example is an "endothermic reaction" because the reaction between NH4Cl and water is making the surrounding cool (cold pack) due to the release of heat.
Hence, the correct answer is "endothermic reaction".
Into which two smaller groups are plants divided.
(a)vascular and nonvascular
(b)seed and seedless
(c)monocots and dicots
(d)seeds and spores
giving 17 points please help
Answers
Because that is the smallest way scientists divide plants your welcome