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3 years ago

Which best describes a radioactive isotope?

Chemistry

1 answer:

sergiy2304 [10]3 years ago

5 0

Answer:

A radioactive isotope, also known as a radioisotope, radionuclide, or radioactive nuclide, is any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays.

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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]

Answer: The percentage yield of aspirin is 38.02 %.

Explanation:

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

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

For salicylic acid:

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

Which statement best describes the relationship between the giraffe and the tree shown above?

Dominik [7]

Answer

Explanation:

the giraffe doesn't need carbon dioxide

8 0

3 years ago

What is the law of fossil succession?:

nata0808 [166]

Different Fossil organisms succeed one another to go up through the different rock layers in a definite and determinable order. Therefore, any time period can be recognized by its fossil content

Explanation:

Different Fossil organisms succeed one another to go up through the different rock layers in a definite and determinable order. Therefore, any time period can be recognized by its fossil content

3 0

2 years ago

Calculate the maximum amount of useful work that can be obtained and comment on the spontaneity for the reaction at 25C :

harkovskaia [24]

Answer:

$1.41 *10^{3} kJ/mol$

Explanation:

First, we find in the tables the ΔH of formation of each compound. As you can see in the (image 1)

Then we solve the ecuation for ΔH°reaction

ΔH°reaction=∑ΔH°f(products)−∑ΔH°f(Reactants)

ΔH°reaction= (-2* 393.5 - 2*285.8) - (52.4 + 0) kJ/mol

ΔH°reaction = -1.41 *10^3 kJ/mol

3 0

3 years ago

For the gas phase decomposition of 1-bromopropane, CH3CH2CH2BrCH3CH=CH2 + HBr the rate constant at 622 K is 6.43×10-4 /s and the

ladessa [460]

Answer is: activation energy of this reaction is 212,01975 kJ/mol.
Arrhenius equation: ln(k₁/k₂) = Ea/R (1/T₂ - 1/T₁).
k₁ = 0,000643 1/s.
k₂ = 0,00828 1/s.

T₁ = 622 K.

T₂ = 666 K.

R = 8,3145 J/Kmol.

1/T₁ = 1/622 K = 0,0016 1/K.
1/T₂ = 1/666 K = 0,0015 1/K.
ln(0,000643/0,00828) = Ea/8,3145 J/Kmol · (-0,0001 1/K).
-2,55 = Ea/8,3145 J/Kmol · (-0,0001 1/K).
Ea = 212019,75 J/mol = 212,01975 kJ/mol.

4 0

3 years ago