Tollens's test shows the presence of aldehydes . a positive Tollens's test appears as a silver precipitate . a negative Tollens's test appears as presence of ketone.
Tollens's test is a chemical test used to differentiate between aldehydes and ketones. In this test, a solution called Tollens's reagent, which contains silver nitrate and ammonia, is used to detect the presence of aldehydes. When an aldehyde is present, it undergoes oxidation by reacting with the Tollens's reagent, forming a silver precipitate.
A positive Tollens's test is indicated by the formation of this silver precipitate, which appears as a shiny silver layer on the inside of the test tube. This silver layer is also referred to as a "silver mirror." This reaction occurs because the aldehyde group is oxidized to a carboxylic acid, while the silver ions in the Tollens's reagent are reduced to metallic silver.
On the other hand, a negative Tollens's test means that no aldehyde is present, and thus, no silver precipitate forms. This is typically observed when a ketone is present in the test sample, as ketones do not readily undergo oxidation like aldehydes do. In this case, the test tube remains clear or slightly cloudy, depending on the reaction conditions and the substances being tested.
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Complete question is :-
tollens's test shows the presence of aldehydes . a positive tollens's test appears as a silver precipitate . a negative tollens's test appears as ______.
which of the following is true about the absorption and metabolism of alcohol? alcohol is metabolized by most tissue and organs in the body. the majority of alcohol is absorbed in the stomach. men and women do not metabolize alcohol at significantly different rates. acetaldehyde produced during alcohol metabolism is highly toxic.
The statement "acetaldehyde produced during alcohol metabolism is highly toxic" is true about absorption and metabolism of alcohol. Option 4 is correct.
Acetaldehyde is a byproduct of alcohol metabolism, and it is a toxic substance that can cause various symptoms such as facial flushing, nausea, and headache. Acetaldehyde is rapidly converted to acetate by the enzyme aldehyde dehydrogenase, which is then metabolized further to carbon dioxide and water.
However, if alcohol is consumed at a high rate, the liver may not be able to metabolize all of the acetaldehyde, leading to a buildup of this toxic substance in the body. This can result in more severe symptoms such as vomiting, rapid heartbeat, and difficulty breathing. Therefore, it is important to consume alcohol in moderation and allow enough time for the liver to metabolize the alcohol and its byproducts. Hence Option 4 is correct.
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calculate the engery of a photon needed to cause an electron in the 3s orbital to be excited to tthe 3p orbital
The energy of the photon needed to cause an electron in the 3s orbital to be excited to the 3p orbital is approximately 3.04 × [tex]10^{-18}[/tex] J (or about 1.90 eV).
To calculate the energy of a photon needed to cause an electron in the 3s orbital to be excited to the 3p orbital, we need to know the energy difference between these two orbitals.
The energy of an electron in a hydrogenic atom (an atom with one electron) can be calculated using the following formula:
[tex]E = - (Z^2 * Ry) / n^2[/tex]
where Z is the atomic number, Ry is the Rydberg constant (2.18 × [tex]10^{-18}[/tex]J), and n is the principal quantum number.
The energy difference between the 3s and 3p orbitals can be calculated by subtracting the energy of the 3s orbital from the energy of the 3p orbital.
For hydrogen, the energy of the 3s orbital is:
E(3s) = - ([tex]1^2[/tex]* 2.18 × [tex]10^{18}[/tex] J) / [tex]3^2[/tex]
E(3s) = - 0.242 ×[tex]10^{18}[/tex] J
And the energy of the 3p orbital is:
E(3p) = - ([tex]1^2[/tex] * 2.18 × [tex]10^{-18}[/tex] J) / 2^2
E(3p) = - 0.546 × [tex]10^{-18}[/tex] J
The energy difference between the two orbitals is:
ΔE = E(3p) - E(3s)
ΔE = (- 0.546 ×[tex]10^{18}[/tex] J) - (- 0.242 ×[tex]10^{-18}[/tex] J)
ΔE = - 0.304 × [tex]10^{-18}[/tex]J
This energy difference represents the energy required to excite an electron from the 3s orbital to the 3p orbital.
To calculate the energy of the photon needed to provide this energy, we use the formula:
E = hν
where E is the energy of the photon, h is Planck's constant (6.626 × [tex]10^{-34}[/tex]J·s), and ν is the frequency of the photon.
Rearranging this formula to solve for the frequency of the photon, we get:
ν = E / h
Substituting the energy difference we calculated, we get:
ν = (- 0.304 × [tex]10^{18}[/tex] J) / (6.626 × [tex]10^{-34}[/tex] J·s)
ν = - 4.59 × [tex]10^{15}[/tex]Hz
Finally, to calculate the energy of the photon, we use the formula:
E = hν
Substituting the frequency we calculated, we get:
E = (6.626 ×[tex]10^{-34}[/tex] J·s) x (- 4.59 × [tex]10^{15}[/tex] Hz)
E = - 3.04 × [tex]10^{-18}[/tex]J
Therefore, the energy of the photon needed to cause an electron in the 3s orbital to be excited to the 3p orbital is approximately 3.04 × 10^-18 J (or about 1.90 eV).
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addictive substances, for which demand is inelastic, are products for which producers can pass higher costs on to consumers.
The statement is correct. Producers of addictive substances, for which demand is inelastic, can pass higher costs on to consumers.
Inelastic demand refers to a situation where changes in price have little effect on the quantity demanded of a product. Addictive substances, such as tobacco or drugs, often have inelastic demand because users are willing to pay high prices for the product regardless of changes in price.
Producers of addictive substances can take advantage of this inelastic demand by increasing prices without seeing a significant decrease in demand. This means that they can pass on any higher costs, such as increased taxes or production costs, to the consumers, who are likely to continue purchasing the product even at a higher price.
This is often seen in the tobacco industry, where governments may increase taxes on cigarettes as a way to discourage smoking, but the tobacco companies can simply pass on the higher costs to consumers who continue to buy the product.
Therefore, it can be concluded that producers of addictive substances, for which demand is inelastic, can pass higher costs on to consumers.
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a 1.25 g sample of co2 is contained in a 750. ml flask at 22.5 c. what is the pressure of the gas, in atm?
The pressure of gas is 1.05 atm when a 1.25 g sample of CO₂ is contained in a 750ml flask at 22.5°C.
Molecular weight of CO₂ is 1.25g ,Volume of CO₂ is 750ml,Temperature of CO₂ is 22.5°C and the gas constant is 0.08206 L atm/mol K.
Using the ideal gas law equation the pressure is found to be 1.05 atm.
To calculate the pressure of the gas, we can use the ideal gas law equation: [tex]PV=nRT[/tex]
Where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin.
First, we need to convert the volume to liters by dividing by 1000: 750 ml = 0.75 L.
Next, we need to calculate the number of moles of CO₂ present in the flask. We can use the molecular weight of CO₂ to convert from grams to moles:
[tex]1.25 * (1 /44.01 ) = 0.0284 mol[/tex]
Now we can plug in the values into the ideal gas law equation:
[tex]PV=nRT[/tex]
[tex]P * 0.75 L = 0.0284 mol * 0.08206 L*atm/mol*K * (22.5 + 273.15) K[/tex]
Simplifying and solving for P, we get:
[tex]P = (0.0284 * 0.08206 * 295.65) / 0.75 = 1.05 atm[/tex]
Therefore, the pressure of the gas in the flask is 1.05 atm.
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