Question

How many Grams of C₆H₆ must decompose according to the following chemical equation to transfer 430kj of heat?

C₆H₆(l) → 3 C₂H₂(g)∆H= 630 kj

Answer 1

THE NUMBER OF GRAMS OF
`C_6H_6` PRODUCED IS
`58.23812 g`

Step-by-step explanation:

The given equation is ,

• 
  `C_6H_6(l)`⇒
  `3C_2H_2(g)`

ΔH=
`630kJ`;

• Thus , for one mole of
  `C_6H_6` we will require
  `630kJ` of energy to completely convert it into 3 moles of
  `3C_2H_2`.

• Thus by giving ,
  `430kJ` of energy ,

the number of moles '
`n`' that will decompose is :

`n=(430)/(630)  \\\\n=(43)/(63) \\n=0.68254`

Thus,

The number of grams
`w` = no.of moles
`*` weight of one mole

weight of one mole = 6
`*`(mass of one mole of
`C`) + 6
`*`(mass of one mole of
`H`)

• weight of one mole =
  `6*12+6*1\\=72+6\\=78`;

• 
  `w=0.68254*(78)\\w=58.23812 g`

Answer 2

53·32 g

Step-by-step explanation:

Given the ΔH for the reaction is for 1 mole of benzene(C6H6) and 1 mole of benzene contains 78 g of benzene

So for 78 g of benzene ΔH of the reaction is 630 kJ

Let the weight of benzene that must decompose to transfer 430 kJ of heat be m g

∴ 78 ≡ 630

m ≡ 430

For 1 kJ of heat to be transferred the weight of benzene required is 78 ÷ 630 = 0·124 g

For 430 kJ of heat to be transferred the weight of benzene required is 0·124 × 430 = 53·32 g

∴ m = 53·32 g

∴ 53·32 grams of C6H6 must decompose according to the given chemical equation to transfer 430 kJ of heat