Recrystallizing an anhydride (such as the product of this reaction) from water or an alcohol is rarely a good idea. explain why. be specific.
Final answer:
Recrystallization of an anhydride in water or alcohol is not effective because anhydrides will react with these solvents to form carboxylic acids or esters, respectively, thereby altering the compound instead of purifying it.
Explanation:
Recrystallizing an anhydride from water or an alcohol is often not ideal due to the reactive nature of anhydrides. Anhydrides undergo hydrolysis in the presence of water to form carboxylic acids, a process which is energetically favorable and further driven by the stabilization through hydrogen-bonding interactions among water molecules and the carboxylic acids. Moreover, anhydrides react with alcohols to yield esters. This means that instead of recrystallizing the anhydride, you are likely to convert it to other products, which defeats the purpose of recrystallization since you want to purify the anhydride, not change its chemical structure.
What is the standard emf of a galvanic cell made of a cd electrode in a 1.0 m cd(no3)2 solution and a cr electrode in a 1.0 m cr(no3)3 solution at 25°c?
The standard emf of a galvanic cell with a Cd and Cr electrode in solutions of their respective 1.0 M nitrates at 25°C is 0.34 V.
Explanation:To determine the standard emf of a galvanic cell made of a Cd electrode in a 1.0 M Cd(NO₃)₂ solution and a Cr electrode in a 1.0 M Cr(NO₃)₃ solution at 25°C, we must first identify the half-reactions taking place at each electrode and their standard reduction potentials (E°).
The standard half-cell potentials (available in standard reduction potential tables) for Cd2+ and Cr3+ are as follows:
The cathode is where reduction takes place, so the Cr3+ half-reaction will be the reduction (gain of electrons), and the Cd2+ half-reaction will be the oxidation at the anode (loss of electrons).
Next, we calculate the standard cell potential (E°cell) using the formula:
E°cell = E°cathode - E°anode
Since the Cr3+ half-reaction has the more negative standard reduction potential, it will be reversed to represent oxidation when it functions as the anode reaction. This gives us:
E°cell = (-0.40 V) - (-0.74 V) = 0.34 V
The positive standard cell potential indicates that the galvanic cell reaction is spontaneous under standard state conditions.
The normal boiling point of ethanol (c2h5oh) is 78.3 °c and its molar enthalpy of vaporization is 38.56 kj/mol. what is the change in entropy in the system in j/k when 42.2 grams of ethanol at 1 atm condenses to a liquid at the normal boiling point?
The change in the randomness of the system is the entropy change. The entropy change after condensation at the standard boiling point is 84.64 J/K.
What is the entropy change?When a system undergoes the addition or deletion of the reactant and the products, then the disorder of the system is known as entropy change.
Given,
Enthalpy of vaporization = 38560 J/mol
Boiling point temperature = 351.3 K
[tex]\begin{aligned}\text{Entropy change of vaporization} &= \dfrac{\text{enthalpy of vaporization}}{\text{boiling point temperature}}\\\\&= \dfrac{38560}{351.3}\\\\&=109.76 \;\rm J/K/mol\end{aligned}[/tex]
Here, liquid has less entropy than gas hence the change in entropy is -109.76 J/K/mol.
Moles of ethanol is calculated as:
[tex]\begin{aligned}\rm moles &= \dfrac{\rm mass}{\rm molar\; mass}\\\\&= \dfrac{42.2}{46}\\\\&= 0.92 \;\rm moles\end{aligned}[/tex]
If 1 mole of ethanol has an entropy change of -109.76 J/K/mol. Then, 0.92 moles will have,
[tex]\dfrac{-109.76 \times 0.92}{1} = 84.64\;\rm J/K[/tex]
Therefore, 84.64 J/K is the entropy change.
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2,2-dimethyl-4-propyloctane has how many secondary carbons? view available hint(s) 2,2-dimethyl-4-propyloctane has how many secondary carbons? five nine six seven
The molecule 2,2-dimethyl-4-propyloctane has five secondary carbons which are those bonded to two other carbon atoms.
Explanation:The hydrocarbon 2,2-dimethyl-4-propyloctane belongs to the class of alkanes, characterized by single bonds between carbon atoms. This molecule consists of an 8-carbon chain (octane), with three side branches: two methyl groups (-CH3) on the second carbon and a propyl group (-CH2-CH2-CH3) on the fourth carbon. When identifying secondary carbons, which are carbon atoms bonded to two other carbon atoms, it becomes evident that 2,2-dimethyl-4-propyloctane contains five secondary carbons.
The two carbons on either end of the main chain don't fit the criteria of secondary carbons as they are bonded to only one other carbon atom. The five secondary carbons are as follows: two from the main chain (excluding the ends); two found at the ends of the propyl branch; and one where the methyl branches connect to the main chain.
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Calculate the k sp for zinc hydroxide if the solubility of zn (oh)2 in pure water is 2.1 × 10-4 g/l. calculate the k sp for zinc hydroxide if the solubility of zn (oh)2 in pure water is 2.1 × 10-4 g/l. 2.9 × 10-3 1.5 × 10-3 9.9 × 10-18 3.8 × 10-17
The [tex]\( K_{sp} \)[/tex] for zinc hydroxide is [tex]\[ 3.8 \times 10^{-17}}\][/tex]
1. Molar mass of [tex]\( \text{Zn(OH)}_2 \)[/tex]:
[tex]\[ \text{Zn} = 65.38 \, \text{g/mol}, \, \text{O} = 16.00 \, \text{g/mol}, \, \text{H} = 1.01 \, \text{g/mol} \][/tex]
[tex]\[ \text{Molar mass} = 65.38 + 2 \times (16.00 + 1.01) = 99.40 \, \text{g/mol} \][/tex]
2. Molar solubility [tex]\( s \)[/tex]:
[tex]\[ \text{Solubility} = 2.1 \times 10^{-4} \, \text{g/L} \][/tex]
[tex]\[ s = \frac{2.1 \times 10^{-4}}{99.40} \approx 2.11 \times 10^{-6} \, \text{mol/L} \][/tex]
3. Ksp expression:
[tex]\[ \text{Zn(OH)}_2 \rightleftharpoons \text{Zn}^{2+} + 2\text{OH}^- \][/tex]
[tex]\[ K_{sp} = [\text{Zn}^{2+}][\text{OH}^-]^2 = s \cdot (2s)^2 = 4s^3 \][/tex]
4. Calculate [tex]\( K_{sp} \):[/tex]
[tex]\[ K_{sp} = 4 \times (2.11 \times 10^{-6})^3 = 4 \times 9.39 \times 10^{-18} \approx 3.76 \times 10^{-17} \][/tex]
Which of the following compounds is not ionic?
A. CaCI2
B. NaI
C. CO2
D. Na2O
(P.S. All the 2's are subscript!)
A solution of 0.90 g of an unknown nonelectrolyte in 100 ml of water at 27◦c has an osmotic pressure of 0.55 atm. what is the molecular weight of this compound? (assume
suppose you like to listen to two different radio stations. The opera station broadcasts at 90.5 MHz and the rock and roll station broadcasts at 107.0 MH.s. which station's signal has waves with longer wavelenghts and which stations signal has station has waves with higher energy?
The rock and roll station at [tex]107.0 MHz[/tex] has higher energy photons with approximately [tex]\(7.09 \times 10^{-26}\) joules[/tex]
The opera station at [tex]90.5 MHz[/tex] has lower energy photons with approximately [tex]\(5.99 \times 10^{-26}\) joules.[/tex]
To determine which radio station's signal has longer wavelengths and which has higher energy, we need to use the relationships between frequency, wavelength, and energy for electromagnetic waves.
1. Wavelength
The wavelength (\(\lambda\)) of a wave is related to its frequency ([tex]\(f\)[/tex]) and the speed of light ([tex]\(c\)[/tex]) by the equation:
[tex]\[ \lambda = \frac{c}{f} \][/tex]
Where:
[tex]\(c\)[/tex] is the speed of light ([tex]\(3 \times 10^8\) meters per second[/tex]).
[tex]\(f\)[/tex] is the frequency of the wave.
Opera Station ([tex]90.5 MHz[/tex])
Frequency: [tex]\(90.5 \times 10^6\) Hz[/tex]
[tex]\[ \lambda_{\text{opera}} = \frac{3 \times 10^8 \, \text{m/s}}{90.5 \times 10^6 \, \text{Hz}} = \frac{3 \times 10^8}{90.5 \times 10^6} = 3.31 \, \text{meters} \][/tex]
Rock and Roll Station ([tex]107.0 MHz[/tex])
Frequency: [tex]\(107.0 \times 10^6\) Hz[/tex]
[tex]\[ \lambda_{\text{rock}} = \frac{3 \times 10^8 \, \text{m/s}}{107.0 \times 10^6 \, \text{Hz}} = \frac{3 \times 10^8}{107.0 \times 10^6} = 2.80 \, \text{meters} \][/tex]
The opera station at [tex]90.5 MHz[/tex] has a longer wavelength of approximately [tex]3.31 meters[/tex].
The rock and roll station at [tex]107.0 MHz[/tex] has a shorter wavelength of approximately [tex]2.80 meters[/tex]
2. Energy
The energy ([tex]\(E\)[/tex]) of a photon is related to its frequency ([tex]\(f\)[/tex]) by the equation:
[tex]\[ E = h f \][/tex]
Where:
[tex]\(h\)[/tex] is Planck's constant ([tex]\(6.626 \times 10^{-34}\) Joule seconds[/tex]).
[tex]\(f\)[/tex] is the frequency of the wave.
Opera Station ([tex]90.5 MHz[/tex])
[tex]\[ E_{\text{opera}} = 6.626 \times 10^{-34} \, \text{Js} \times 90.5 \times 10^6 \, \text{Hz} = 5.99 \times 10^{-26} \, \text{J} \][/tex]
Rock and Roll Station ([tex]107.0 MHz[/tex])
[tex]\[ E_{\text{rock}} = 6.626 \times 10^{-34} \, \text{Js} \times 107.0 \times 10^6 \, \text{Hz} = 7.09 \times 10^{-26} \, \text{J} \][/tex]
A 642 mL sample of oxygen gas at 23.5°C and 795 mm Hg, is heated to 31.7°C and the volume of the gas expands to 957 mL. What is the new pressure in atm?
¿A shaker of salt substitute contains 1.6 oz of K. What is the activity, in milliCuries, of the potassium in the shaker? The activity is 7 microcuries (µCi)
The jaeger reading cards are used to test _____ vision
The Jaeger reading cards are used to test near vision. The correct answer is "near" vision.
The Jaeger reading cards are used to test near vision, which is the ability to see objects clearly at a close distance, typically around 14 to 16 inches away from the eyes. This type of vision is important for activities such as reading, writing, and working on a computer. The Jaeger chart consists of blocks of text in various sizes, with the smallest print at the bottom and the largest at the top. A person being tested reads the text from top to bottom until they can no longer clearly distinguish the letters, which helps determine their near visual acuity.
Complete the reactions to show how butanoic acid may be converted to butanal.
Final answer:
Butanoic acid can be converted to butanal via a reduction process using a reducing agent such as lithium aluminum hydride, followed by hydrolysis.
Explanation:
Converting butanoic acid to butanal involves a reduction process, which can be carried out using reducing agents such as lithium aluminum hydride (LiAlH₄) or borane (BH₃). The reaction with LiAlH₄ is usually carried out in dry ether as a solvent, and it can be followed by careful hydrolysis to give the aldehyde, butanal. The overall reaction can be summarized as:
Butanoic acid (C₄H₈O₂) is treated with the reducing agent LiAlH₄.
The acid is reduced to the corresponding aldehyde, butanal (C₄H₈O).
After the reduction, the reaction mixture is hydrolyzed, which involves adding water to the reaction mixture.
This is different from esterification, which is the reaction between an acid and an alcohol, as described in the esterification of ethanol and butanoic acid to form ethyl butanoate and water.
The biochemical production of butanol from butyric acid is similarly not a direct route for synthesizing butanal, but it is an important process for biomass conversion.
What is the daughter nucleus (nuclide) produced when 90sr undergoes beta decay by emitting an electron? replace each question mark with the appropriate integer or symbol?
Final answer:
The daughter nuclide produced when ¹°Sr undergoes beta decay is ¹°Y (yttrium-90), which is represented by the nuclear equation ¹°Sr → ¹°Y + β⁻.
Explanation:
When ¹°Sr undergoes beta decay, it emits an electron (beta particle) and transforms into a different element. The loss of the electron results in an increase of the atomic number by one while the mass number remains the same. Therefore, the new atomic number will be 39 (as strontium has atomic number 38), and the mass number stays at 90. The daughter nuclide produced from this decay is ¹°Y (yttrium-90).
The nuclear equation for this ß-decay process is:
¹°Sr → ¹°Y + β⁻
To lift a load of 100 N a distance of 1 m an effort of 25 N must be applied over an inclined plane of length 4 m. What must be done to lift the load 2 m, using the same effort? A.Use an inclined plane of length 8 m.
B.Use an inclined plane of length 2 m.
C.Use an inclined plane of length 10 m
D.Use an inclined plane of length 16 m.
Answer: The correct answer is A) Use an inclined plane of 8 m
Work :
Work is defined as force applied to an object to move it to some distance . It is calculated as product of force and displacement .
W = F* d
Where : W =work (N-m) F = force (N) d = displacement (m)
When a body is lifted , work can be expressed as :
W = m*g*h ( h = height )
Also force due to gravitation can be given as
F = m* g
where :
g = gravitational acceleration ([tex] 9.8 \frac{m}{s^2} [/tex]
Hence Work can be written as : W = F * h
Given :
Force on load due to gravitation = 100 N Height = 2 m
Force applied = 25 N displacement = ?
Work done to lift the load to 2 m = F * h
= 100 N * 2 m = 200 N-m
Plugging W = 200 N-m in work formula
W = F* d
200 N-m = 25 N * d
Dividing both side by 25 N
[tex] \frac{200N-m}{25 N} = \frac{25 N * d}{25 N} [/tex]
d = 8 m
Hence, to lift the load using 25 N , the inclined plane of 8 m can be used .
A 135 g sample of carbon disulfide requires 43.2 kj of heat to vaporize completely. what is the enthalpy of vaporization for carbon disulfide?
a. 1.77 kj/mol
b. 24.4 kj/mol
c. 76.2 kj/mol
d. 0.320 kj/mol
e. 3.13 kj/mol
hi i'm having trouble solving this question
" if 7.54 grams of Al reacts with excess of H2SO4, and makes 0.33g of H2 . What is the % yield of H2gas produced?
How many compounds, of the ones listed below, have hydrogen bonding? ch3(ch2)2nh2 ch3(ch2)2nh(ch2)4ch3 (ch3ch2)2n(ch2)4ch3?
The correct answer is a. 2 compounds have hydrogen bonding among the listed below.
To determine how many of the given compounds have hydrogen bonding, we must identify if they have hydrogen atoms attached to highly electronegative atoms like nitrogen (N), oxygen (O), or fluorine (F).
The compounds listed are:
CH₃(CH₂)₂NH₂CH₃(CH₂)₃NH(CH₂)₂CH₃(CH₃CH₂)₂N(CH₂)₄CH₃Analysis
CH₃(CH₂)₂NH₂: Contains an N-H bond, so it can form hydrogen bonds.CH₃(CH₂)₃NH(CH₂)₂CH₃: Contains an N-H bond, so it can form hydrogen bonds.(CH₃CH₂)₂N(CH₂)₄CH₃: Does not contain an N-H bond, so it cannot form hydrogen bonds.Based on this analysis, 2 out of the 3 compounds can form hydrogen bonds. Therefore, the correct answer is a. 2.
Correct question is: How many compounds, of the ones listed below, have hydrogen bonding?
CH₃(CH₂)₂NH₂ , CH₃(CH₂)₃NH(CH₂)₂CH₃ , (CH₃CH₂)₂N(CH₂)₄CH₃ ?
a. 2
b. 1
c. 0
d. 3
A 36.41-g sample of calcium carbonate (CaC O 3 )
contains 14.58 g of calcium and 4.36 g of carbon.
What is the mass of oxygen contained in the sam-
ple? What is the percent by mass of each element in
this compound?
Which carbonyl compounds do not undergo an aldol reaction when treated with −oh in h2o? select all that apply?
Carbonyl compounds that do not undergo an aldol reaction include those without alpha-hydrogens like formaldehyde and benzaldehyde, as well as esters, acids, and amides.
These compounds either lack necessary alpha-hydrogens or have structures that are unfavorable for aldol reactions.
In an aldol reaction, carbonyl compounds like aldehydes and ketones with alpha-hydrogens can react in the presence of a base such as hydroxide (−OH) in water. However, not all carbonyl compounds undergo this reaction.
Carbonyl compounds that do not undergo an aldol reaction include those without alpha-hydrogens, such as formaldehyde and benzaldehyde. Additionally, carbonyl compounds like esters, acids, and amides typically do not participate in aldol reactions due to their structural properties.
Examples of Carbonyl Compounds Not Undergoing Aldol Reaction:
Formaldehyde (H-CHO)Benzaldehyde (C₆H₅CHO)Ester (R-COOR')Acid (R-COOH)Amide (R-CONH₂)These compounds either lack the necessary alpha-hydrogens or have structures that are unfavorable for aldol reactions.
Which particle changes the mass of the isotope the most? which particle changes the mass of the isotope the most? electron capture positron emission gamma capture alpha particle neutron particle?
Answer: Option (d) is the correct answer.
Explanation:
Species which contain same number of protons but different number of neutrons are known as isotope.
For example, [tex]^{1}_{1}H[/tex] and [tex]^{3}_{1}H[/tex] are isotopes.
More is the mass of particle colliding with the isotope more will be the change in mass of an isotope due to emission of a heavier particle.
As alpha ([tex]^{4}_{2}He[/tex]) particle is heavier then a neutron, positron and gamma particles.
For example, [tex]^{14}_{7}N + ^{4}_{2}He \rightarrow ^{17}_{8}O[/tex]
Therefore, we can conclude that alpha particle changes the mass of the isotope the most.
If 32.5 grams of CaO are dissolved in 212 grams of water, what is the concentration of the solution in percent by mass?
6.52% CaO
8.67% CaO
13.3% CaO
15.3% CaO
Answer:
Concentration of solution in percent by mass is 13.3% CaO
Explanation:
% by mass = [tex]\frac{mass of solute}{mass of solution}\times 100[/tex]
Here solute is CaO and solvent is water.
So, mass of solution = (mass of solute)+(mass of solvent)
= (mass of CaO)+(mass of water)
= 32.5 g + 212 g
= 244.5 g
So, Concentration of solution by percent mass = [tex]\frac{mass of CaO}{mass of solution}\times 100[/tex] = [tex]\frac{32.5}{244.5}\times 100[/tex] = 13.3 %
Write the balanced nuclear equation for β− decay of sodium−26. include both the mass numbers and the atomic numbers with each nuclear symbol. use the sup-subscript button in the answer palette to enter these numbers correctly. greek letters can be accessed in the drop-down menu that says -select−.
The balanced nuclear equation for beta decay of sodium-26 is represented as Na²⁶₁₁ → Mg²⁶₁₂ + β₋₁⁰ + energy.
What is beta decay?Beta decay is one of the type of radioactive nuclear decay reaction in which emission of a beta particle takes place from the atomic nuclear.
Beta particle define by the symbol β₋₁⁰ i.e. this particles has no mass but having a negative charge on it. In this reaction atomic mass of the parent atom is equal to the new formed daughter atom. But in this reaction number of neutron is reduced by 1 and number of proton is increased by one of parent atom. So, balanced nuclear equation for β− decay of sodium−26 is represnted as:
Na²⁶₁₁ → Mg²⁶₁₂ + β₋₁⁰ + energy
Hence balanced nuclear equation for the beta decay is represented above.
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A sample of seawater contains 1.3g of calcium ions in 3,100kg of solution. what is the calcium ion concentration of this solution in units of ppm?
To 100.0 g water at 25.00 ºc in a well-insulated container is added a block of aluminum initially at 100.0 ºc. the temperature of the water once the system reaches thermal equilibrium is 28.00 ºc. what is the mass of the aluminum block? (the specific heat capacity of al is 0.900 j g–1 k–1 .)
The mineral enargite is 48.41% cu, 19.02% as, and 32.57% s by mass. what is the empirical formula of enargite?
Which statement best describes how the scientific community analyzes data?
Answer:
Scientists can come to different conclusions based on the same data
Explanation:
Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. Thus, scientists can come to different conclusions based on the same data is the statement that describes how the scientific community analyzes data.
What is matter?Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas.
So as we saw that matter has some mass so mass can be measured in gram only. Mass can also be represented as number of molecules. We also saw that matter occupy some volume and that volume is measured only in liter. Scientists can come to different conclusions based on the same data is the statement that describes how the scientific community analyzes data.
Thus, scientists can come to different conclusions based on the same data is the statement that describes how the scientific community analyzes data.
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The normal boiling point of water is 100.0 °c and its molar enthalpy of vaporization is 40.67 kj/mol. what is the change in entropy in the system in j/k when 51.1 grams of steam at 1 atm condenses to a liquid at the normal boiling point?
The change in entropy in the system is 308.3 J/K.
Explanation:The change in entropy in the system can be calculated using the formula ∆S = ∆Hvap/T. Here, ∆Hvap is the molar enthalpy of vaporization of water, which is given as 40.67 kJ/mol. T is the temperature in Kelvin, which can be calculated by adding 273.15 to the boiling point of water in Celsius. So, T = 100.0 + 273.15 = 373.15 K. Plugging in these values in the formula, we get:
∆S = (40.67 kJ/mol)/(373.15 K) = 0.1089 kJ/(mol·K)
Now, we need to convert grams of steam to moles of steam. The molar mass of water is 18.015 g/mol. So, 51.1 g of steam is equal to (51.1 g)/(18.015 g/mol) = 2.835 mol. Multipling this with the change in entropy, we get:
∆S = (0.1089 kJ/(mol·K)) · (2.835 mol) = 0.3083 kJ/K
Finally, to convert kJ/K to J/K, we multiply by 1000:
∆S = (0.3083 kJ/K) · (1000 J/1 kJ) = 308.3 J/K
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Sodium is produced by electrolysis of molten sodium chloride. what are the products at the anode and cathode, respectively?
the transfer of a section of DNA from one organism into the DNA of another organism by scientists is called
The transfer of a section of DNA from one organism into the DNA of another organism by scientists is called genetic engineering.
What is DNA?
DNA is a hereditary material which is present in human beings as well as all other living organisms. Every cell which is present in an organism's body has DNA which is the same. Most of the DNA is situated in the cell's nucleus and small amount of it can be found in the cell's mitochondria as well.
Information which is stored in DNA is stored as codes made up of four chemical bases namely, adenine, thymine , cytosine and guanine.Human DNA consists of 3 billion bases .The order of the bases determines information which is required for building and maintaining an organism.
DNA bases are capable of pairing up with each other. Adenine pairs with thymine and guanine pairs up with cytosine .Each base is also attached to a sugar molecule and a phosphate group. A base, phosphate sugar are together called as nucleotides.
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Which of the temperatures below is most likely to be the boiling point of water at 880 torr?view available hint(s)which of the temperatures below is most likely to be the boiling point of water at 880 torr?92°c105°c100°c?
Using the Clausius-Clapeyron equation, we can derive that the boiling point of water at 880 torr is closest to 90°C. Thus, among the given options, the boiling point of water at 880 torr is most likely to be 92°C.
Explanation:The subject question is considering the boiling point of water at differing pressures. The standard boiling point of water is 100°C at 1 atmospheric pressure (or 760 torr). However, boiling point changes with changes in atmospheric pressure.
By using the Clausius-Clapeyron equation, which establishes a relationship between the vapor pressure and temperature of a substance, we can establish that at 880 torr, the boiling point is likely to be close to 90°C, given that the vapor pressure of water is 68kPa at about this temperature. Therefore, among the options given, 92°C is the most likely boiling point of water at 880 torr.
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