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4 years ago

Select the reason why two molecules of benzaldehyde cannot react via the aldol condensation.

1 answer:

4 0

Benzaldehyde or C6H5CHO would not undergo the aldol condensation because it does not contain an alpha-hydrogen in its structure. Aldol condensation is a type of reaction that happens between an enolate and an aldehyde or ketone leading to a alkene that has a planar structure. The lack of an alpha-hydrogen would not allow for it to undergo such process since it cannot enolize. Benzaldehyde undergoes a nucleophilic reaction known as Claisen-Schmidt condensation. It has somehow same mechanism of the aldol reaction however, the nucleophilic attack on the carbonyl happens even without the alpha-hydrogen but with an enolate that is from a ketone.

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In the reaction A + B + C >> D, what are the products?

Kisachek [45]

Answer:

D only

Explanation:

The products are the stuff on the right of the yield sign so the answer is D only.

3 0

3 years ago

How much heat, in kJ, is required to raise the temperature of 50 g of water by 5.53°C? (Round to the nearest 10 kJ, and enter on

Triss [41]

Answer:

$Q=1.16kJ$

Explanation:

Hello,

in this case, the required heat to increase the water by 5.53 °C is computed by using the mass, heat capacity and change in temperature during the process:

$Q=mCp\Delta T$

Thus, for the given data we compute it in kJ:

$Q=50g*4.186\frac{J}{g*\°C}*(5.53\°C)*\frac{1kJ}{1000J} \\\\Q=1.16kJ$

Best regards.

5 0

3 years ago

A mixture of helium, nitrogen and oxygen has a total pressure of 756 mmHg. The partial

Karolina [17]

Answer:

The partial pressure of oxygen in the mixture is 296 mmHg.

Explanation:

The pressure exerted by a particular gas in a mixture is known as its partial pressure. So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone.

This relationship is due to the assumption that there are no attractive forces between the gases.

So, in this case, the total pressure is:

PT=Phelium + Pnitrogen + Poxygen

You know:

PT= 756 mmHg
Phelium= 122 mmHg
Pnitrogen= 338 mmHg
Poxygen= ?

Replacing:

756 mmHg= 122 mmHg + 338 mmHg + Poxygen

Solving:

756 mmHg - 122 mmHg - 338 mmHg = Poxygen

Poxygen= 296 mmHg

<u><em>The partial pressure of oxygen in the mixture is 296 mmHg.</em></u>

6 0

3 years ago

1. What type of wave is shown below?

svlad2 [7]

Answer : The correct option is, transverse wave.

Explanation :

Longitudinal waves : It is defined as the waves in which the particles of the medium move in the direction of the wave.

Transverse wave : It is defined as the waves in which the particles of the medium travel perpendicularly to the direction of the wave.

Surface wave : It is defined as a combination of transverse and longitudinal waves.

From the given image we conclude that, this illustration depict the transverse wave because the particles of the medium move perpendicularly to the direction of the wave.

Hence, the type of wave is, transverse wave

3 0

4 years ago

For a particular first-order reaction, it takes 3.0 minutes for the concentration of the reactant to decrease to 25% of its init

grigory [225]

We will use this formula for first order:
㏑[A] = - Kt +Ao
when we have t (given)= 30 min = 30 x 60 = 1800 s (we here convert time from min to second.
then we assume that the initial concentration Ao = 1
and the concentration of A (final concentration = 0.25
So by substitution:
㏑(0.25) = - K * 1800 + ㏑(1)
1.39 = K * 1800
∴ K = 0.00077 s^-1 or 7.7 x 10^-4

5 0

4 years ago