Chemistry, asked by Anonymous, 1 month ago

You're supercool if you help me solve Q-23 and 24 :D​

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Answers

Answered by rajekalpana25
5

Explanation:

23)C10H10=12×10+10×1=130g/mol

23) option (d).

Answered by ajr111
23

Answer:

23. (D) C₁₀H₁₀

24. (A) C₅H₁₂

Explanation:

23. Let the number of atoms each of Carbon and Hydrogen be x

we know that, the mass of carbon is 12 and hydrogen is 1

So, 12x + 1x = 130 [Rounding off helps us to get answer in a simple way]

=> 13x = 130

=> x = 10

So, number of atoms of C and H are 10

So, the molecular formula is C₁₀H₁₀ [Option D] is the right answer

___________________________

24. Burning 10g of sample, we got 30.5g of CO₂ and 14.98g of H₂O

We know that, Combustion of hydrocarbon is of the form,

C_xH_y + (x + \dfrac{y}{4}) O_2\longrightarrow xCO_2 + \dfrac{y}{2}H_2O

So, Now, with the provided masses of the carbon dioxide and the water, we can calculate the molar amounts of carbon and hydrogen in the sample.

First we calculate the molar masses:

C = 12.011 x 1 = 12.011 g/mol

O = 15.99 x 2 = 31.99 g/mol

CO₂ = 12.011 + 31.99 = 44.001 g/mol

H = 1.008 x 2 = 2.016 g/mol

O = 15.99 x 1 = 15.99 g/mol

H₂O = 2.01 + 15.99 = 18.006 g/mol

Now we obtain the molar amounts of C and H using the obtaines masses of carbon dioxide and water:

mol C = 30.50g CO₂ x (1mol CO₂)/(44.001 g/mol)  x (1mol C)/(1mol CO₂) = 0.6931 mol C

mol H = 14.98g H₂O x (1mol H₂O)/(18.006 g/mol)  x (2mol H)/(1mol H₂O) = 1.6638 mol H

Finally, we can obtain the H/C molar ratio by identifying the smaller whole-number ratio for these molar amounts. For this we can first divide each molar amount by the smaller amount:

mol C = 0.6931/0.6931 = 1

mol H = 1.6638/0.6931 = 2.4

As we are still getting a decimal amount for the hydrogen, what we can do is multiply both molar amounts by the smaller whole multiple that can give us a whole number for the hydrogen's molar amount, in this case, that multiple would be 5:

mol C = 0.6931/0.6931 = 1 x 5 = 5

mol H = 1.6638/0.6931 = 2.4 x 5 = 12

Now we can write the empirical formula for the hydrocarbon, which is:

C₅H₁₂[Option A is the right answer]

Hope it helps!!

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