You visited us 3 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Chemistry

Enthalpy

The polymeriz...

Question

The polymerization of ethylene to linear polyethylene is represented by the reaction,
$n (C H_{2} == C H_{2}) ⟶ - - (- - C H_{2} - - C H_{2} - -) - -_{n}$
where n has large integral value. Given that the average enthalpies of bond dissociation for $C == C$ and $C - - C$ at $298 K$ are $+ 590$ and $+ 331 k J m o l^{- 1}$ respectively.

Calculate the enthalpy of polymerization per mole of ethylene at $298 K$ :

Δ H = - 72 k J m o l^{- 1}

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

Δ H = + 72 k J m o l^{- 1}

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Δ H = 1252 k J m o l^{- 1}

No worries! We‘ve got your back. Try BYJU‘S free classes today!

None of these

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is A $Δ H = - 72 k J m o l^{- 1}$
Polymerisation of ethylene to linear polyethylene is
$n (C H_{2} == C H_{2}) ⟶ - - (- - C H_{2} - - C H_{2} - -) - -_{n}$
In this polymerization reaction, every molecule of ethylene involves breaking of one C = C (double bond) and formed two C-C (single bonds).

$E n e r g y r e l e a s e d = E n e r g y d u e t o f o r m a t i o n o f t w o s i n g l e b o n d s$
$= 2 \times 331$
$= 662 k J m o l e^{- 1}$ of ethylene.
$Δ H_{p o l y m e r i s a t i o n} = 590 - 662$
$= - 72 k J m o l^{- 1}$

Suggest Corrections

Similar questions

Q. The polymerisation of ethylene to linear polyethylene is represented by the reaction

n C H_{2} = C H_{2} \to (- C H_{2} - C H_{2} -) n

where n has a large integral value. Given that average enthalpies of bond dissociation for

C = C

C - C

at 298 K are

+

590 &

+

331 kJ

m o l^{- 1}

respectively. Then the enthalpy of polymerisation per mole of ethylene at 298 K is:

Q. The polymerization of propene is linear. Polypropene is represented by the reaction

Where n has large integral value, the average enthalpies of bond dissociation for (C = C) and (C - C) at 298 K are +590 and

+ 331 K J m o l^{- 1}

respectively. The enthalpy of polymerization is

- 360 K J m o l^{- 1}

. Find the value of n.___

Q. Enthalpy of polymerisation of ethylene, as represented by the reaction,

n C H_{2} = C H_{2} \to (- C H_{2} - C H_{2} -) n

is -100 kJ per mole of ethylene. Given bond enthalpy of C = C bond is 600 kJ mol

^{- 1}

, Determine enthalpy of C C bond (in kJ mol)

Q. The polymerisation of propene to linear polypropene is represented by the reaction:

where n has a large integral value. The average enthalpies of bond dissociation for

(C = C)

and

(C - C)

at 298 K are +590 and

+ 331 {kJmol}^{- 1}

, respectively. The enthalpy of polymerisation is

- 360 {kJmol}^{- 1}

. Find the value of n.

Polymerisation of ethene to poly - ethene is represented by the equation
$n (C H_{2} = C H_{2}) \to (- C H_{2} - C H_{2} -)_{n}$
Given that average enthalpies of C = C and C - C bonds at 298 K are 590 and 331 kJ $m o l^{- 1}$ respectively, predict the enthalpy change when 56g of ethene changes to polyethylene.

Join BYJU'S Learning Program