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3 years ago

Suggest a possible mechanism for the acid catalyzed reaction of a typical ketohexose to give 5-hydroxymethylfurfural.

Chemistry

1 answer:

Brut [27]3 years ago

3 0

Answer:

See explanation

Explanation:

Taking the acid catalysed hydrolysis of fructose C6H12O6, the mechanism begins with the protonation of an -OH group as shown.

This is now followed by dehydration and formation of a keto-enol tautomer. The keto form is now dehydrated followed by the protonation of a second -OH group.

A second dehydration followed by deprotonation leads to the formation of 5-hydroxymethylfurfural.

Image credit: SciElo

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A gas mixture with a total pressure of 745 mmHg contains each of the following gases at the indicated partial pressures: CO2, 24

Setler79 [48]

Answer:

For Part A: The partial pressure of Helium is 218 mmHg.

For Part B: The mass of helium gas is 0.504 g.

Explanation:

For Part A:

We are given:

$p_{CO_2}=245mmHg\\p_Ar}=119mmHg\\p_{O_2}=163mmHg\\P=745mmHg$

To calculate the partial pressure of helium, we use the formula:

$P=p_{CO_2}+p_{Ar}+p_{O_2}+p_{He}$

Putting values in above equation, we get:

$745=245+119+163+p_{He}\\p_{He}=218mmHg$

Hence, the partial pressure of Helium is 218 mmHg.

For Part B:

To calculate the mass of helium gas, we use the equation given by ideal gas:

PV = nRT

or,

$PV=\frac{m}{M}RT$

where,

P = Pressure of helium gas = 218 mmHg

V = Volume of the helium gas = 10.2 L

m = Mass of helium gas = ? g

M = Molar mass of helium gas = 4 g/mol

R = Gas constant = $62.3637\text{ L.mmHg }mol^{-1}K^{-1}$

T = Temperature of helium gas = 283 K

Putting values in above equation, we get:

$218mmHg\times 10.2L=\frac{m}{4g/mol}\times 62.3637\text{ L.mmHg }mol^{-1}K^{-1}\times 283K\\\\m=0.504g$

Hence, the mass of helium gas is 0.504 g.

6 0

3 years ago

15. Which sample of argon gas has the same number of atoms as a 100.-milliliter sample of helium gas at 1.0 atm and 300. K? A) 5

OLga [1]

The sample of argon gas that has the same number of atoms as a 100 milliliter sample of helium gas at 1.0 atm and 300 is 100. mL at 1.0 atm and 300. K

The correct option is D.

<h3>What is the number of moles of gases in the given samples?</h3>

The number of moles of gases in each of the given samples of gas is found below using the ideal gas equation.

The ideal gas equation is: PV/RT = n

where;

P is pressure
V is volume
n is number of moles of gas
T is temperature of gas
R is molar gas constant = 0.082 atm.L/mol/K

Moles of gas in the given helium gas sample:

P = 1.0 atm, V = 100 mL or 0.1 L, T = 300 K

n = 1 * 0.1 / 0.082 * 300

n = 0.00406 moles

For the argon gas sample:

A. n = 1 * 0.05 / 0.082 * 300

n = 0.00203 moles

B. n = 0.5 * 0.05 / 0.082 * 300

n = 0.00102 moles

C. n = 0.5 * 0.1 / 0.082 * 300

n = 0.00203 moles

D. n = 1 * 0.1 / 0.082 * 300

n = 0.00406 moles

Learn more about ideal gas equation at: brainly.com/question/24236411

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8 0

1 year ago

25.0 mL of a hydrofluoric acid solution of unknown concentration is titrated with 0.200 M NaOH. After 20.0 mL of the base soluti

lesantik [10]

Answer:

[HF]₀ = 0.125M

Explanation:

NaOH + HF => NaF + H₂O

Adding 20ml of 0.200M NaOH into 25ml of HF solution neutralizes 0.004 mole of HF leaving 0.004 mole NaF in 0.045L with 0.001M H⁺ at pH = 3. This is 0.089M NaF and 0.001M HF remaining.

=> 45ml of solution with pH = 3 and contains 0.089M NaF from titration becomes a common ion problem.

HF ⇄ H⁺ + F⁻

C(eq) [HF] 10⁻³M 0.089M (<= soln after adding 20ml 0.200M NaOH)

Ka = [H⁺][F⁻]/[HF]₀ => [HF]₀ = [H⁺][F⁻]/Ka

[HF]₀ = (0.001)(0.089)/(7.1 x 10⁻⁴) M = 0.125M

6 0

3 years ago

Two people are pushing on a shopping cart from opposite sides. When will the motion of

Darina [25.2K]

Answer:

The answer is B

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3 years ago

What % of the earth's freshwater is found in glaciers and ice packs? 0.03% 0.03% 3% 3% 24.9% 24.9% 75%

Westkost [7]

Answer:

En verdad solo el 0,025% del agua de la tierra es dulce

Explanation:

7 0

3 years ago