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3 years ago

Select the correct answer.

Chemistry

1 answer:

lorasvet [3.4K]3 years ago

5 0

Answer:

D. the energy release increases the molecular motion but decreases the kinetic

energy of the substance

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Which material is an insulator against electric current?

NemiM [27]

Answer:

b) a rubber tire

Explanation:

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2 years ago

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Which of the following reactions does the coenzyme biotin catalyze?

Papessa [141]

Answer:

c. decarboxylation of an a-keto acid.

Explanation:

Decarboxylation refers to the removal of the carboxyl group from a carboxylic acid and thus releasing carbon dioxide. Decarboxylases are enzymes that speed up the removal of the carboxyl group from acids. These reactants could be amino acids, alpha-keto acids, and beta-keto acids. Biotin is known to catalyze the decarboxylation of malonyl CoA to acetyl CoA during fatty acid synthesis.

Malonyl CoA is converted to acetyl CoA after decarboxylation assisted by biotin also known as Vitamin H. Alpha keto acids are involved in fatty acids synthesis and Malonyl CoA is an alpha-keto acid because the keto group is located in the first carbon near the carboxylic acid group. Keto acids have both a carboxyl group and a ketone group.

5 0

3 years ago

A reaction was performed in which 3.6 g 3.6 g of benzoic acid was reacted with excess methanol to make 1.3 g 1.3 g of methyl ben

Anit [1.1K]

Answer: The percent yield of the reaction is 32.34 %

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For benzoic acid:

Given mass of benzoic acid = 3.6 g

Molar mass of benzoic acid = 122.12 g/mol

Putting values in equation 1, we get:

$\text{Moles of benzoic acid}=\frac{3.6g}{122.12g/mol}=0.0295mol$

The chemical equation for the reaction of benzoic acid and methanol is:

$\text{Benzoic acid + methanol}\rightarrow \text{methyl benzoate}$

By Stoichiometry of the reaction

1 mole of benzoic acid produces 1 mole of methyl benzoate

So, 0.0295 moles of benzoic acid will produce = $\frac{1}{1}\times 0.0295=0.108$ moles of methyl benzoate

Now, calculating the mass of methyl benzoate from equation 1, we get:

Molar mass of methyl benzoate = 136.15 g/mol

Moles of methyl benzoate = 0.0295 moles

Putting values in equation 1, we get:

$0.0295mol=\frac{\text{Mass of methyl benzoate}}{136.15g/mol}\\\\\text{Mass of methyl benzoate}=(0.0295mol\times 136.15g/mol)=4.02g$

To calculate the percentage yield of methyl benzoate, we use the equation:

$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Experimental yield of methyl benzoate = 1.3 g

Theoretical yield of methyl benzoate = 4.02 g

Putting values in above equation, we get:

$\%\text{ yield of methyl benzoate}=\frac{1.3g}{4.02g}\times 100\\\\\% \text{yield of methyl benzoate}=32.34\%$

Hence, the percent yield of the reaction is 32.34 %

6 0

3 years ago

Based on the table, which do you think is larger – your direct water use or your indirect water use?

Pavlova-9 [17]

Answer:

your indirect water use.

5 0

3 years ago

Complete the reaction, which is part of the electron transport chain. The abbreviation FMN represents flavin mononucleotide. Use

Margarita [4]

Answer:

1. NADH + H⁺ + FMN + Q ⟶ NAD⁺ + FMN + QH₂

2. The reactant that is reduced is Q

3. The charge on iron on the right side is +2, Fe²⁺

Explanation:

NADH + H⁺ + FMN + Q ⟶ NAD⁺ + FMN + QH₂

The reaction above is catalysed by NADH:ubiquinone oxidoreductase (complex 1), which transfers a hydride ion from NADH to FMN, from which two electrons pass through a series of of Fe-S centers to the iron-sulfur protein N-2. Electron transfer from N-2 to Ubiquinone forms QH₂

The species in a reaction which gains hydrogen irons is reduced, Therefore, the reactant that is reduced is Q, ubiquinone to form QH₂, ubiquinol.

To determine the oxidation number of iron on the right side of the reaction below,

QH2 + 2cyt c ( Fe3+) ⟶ Q + 2cyt c(Fex) + 2H^+

Sum of charges on the left side = Sum of charges on the right side

Sum of charges on the left side = 2 *+3 = +6

Therefore 2 * x + 2= 6

2x = 6 -2 = 4

x = 4/

x = 2

Therefore the charge on iron on the right side is +2, Fe²⁺

4 0

3 years ago