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adelina 88 [10]

3 years ago

9

Which of the following is true about chemical reactions. A. they are accompanied by changes in energy. B. they form new substanc

es with new properties. C. both A & B
D.neither A nor B

1 answer:

Ilia_Sergeevich [38]3 years ago

7 0

The correct answer should be option C. hope this helps

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Aspirin sun thesis Green Chemistry and Assime the aspirin is prepared by the following reaction and that 10.09. of salicylic aci

klemol [59]

<u>Answer:</u> The percentage yield of aspirin is 38.02 %.

<u>Explanation:</u>

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

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

<u>For salicylic acid:</u>

Given mass of salicylic acid $(C_7H_6O_3)$ = 10.09 g

Molar mass of salicylic acid $(C_7H_6O_3)$ = 138.12 g/mol

Putting values in equation 1, we get:

$\text{Moles of salicylic acid}=\frac{10.09g}{138.12g/mol}=0.0730mol$

The chemical equation for the formation of aspirin follows:

$C_7H_6O_3+C_4H_6O_3\rightarrow C_9H_8O_4+CH_3COOH$

As, acetic anhydride is present in excess. So, it is considered as an excess reagent.

Thus, salicylic acid is a limiting reagent because it limits the formation of products.

By Stoichiometry of the reaction:

1 mole of salicylic acid produces 1 mole of aspirin.

So, 0.0730 moles of salicylic acid will produce = $\frac{1}{1}\times 0.0730=0.0730mol$ of aspirin

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

Molar mass of aspirin = 180.16 g/mol

Moles of aspirin = 0.073 moles

Putting values in equation 1, we get:

$0.073mol=\frac{\text{Mass of aspirin}}{180.16g/mol}\\\\\text{Mass of aspirin}=13.15g$

To calculate the percentage yield of aspirin, we use the equation:

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

Experimental yield of aspirin = 5.0 g

Theoretical yield of aspirin = 13.15 g

Putting values in above equation, we get:

$\%\text{ yield of aspirin}=\frac{5.0g}{13.15g}\times 100\\\\\% \text{yield of aspirin}=38.02\%$

Hence, the percent yield of aspirin is 38.01 %.

6 0

3 years ago

Describe the effects of heat on rocks

Monica [59]

Answer:

rocks main constituent is calcium carbonate, which produce carbon dioxide and calcium oxide (quick lime) upon heating

6 0

3 years ago

PLS ANSWER QUICKLY

vichka [17]

1. D
2. DR
3. SR
4. DR
5. C
6. SR
7. S
8. D
10. C

3 0

3 years ago

isotopes of an element will always have the same a. number of protons. b. number of neutrons. c. number of electrons. d. mass.

Nastasia [14]

Your answer is same number of protons

3 0

3 years ago

What is the half life of the graphed material?

daser333 [38]

Answer:

3 hours

Explanation:

To know the the correct answer to the question given above, it is important we know the definition of half-life.

The half-life of a substance is simply defined as the time taken for half the substance to decay.

Considering the diagram given above, the initial mass of the substance is 100 g.

Half of the initial mass = 100 / 2 = 50 g

Now, we shall determine the time from the graph taken to get to 50 g.

Considering the diagram given above, the time taken to get to 50 g is 3 hours.

Therefore, the half-life of the material is 3 hours.

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3 years ago