Question:
The heat of polymerization of ethylene is 25 Kcal/mol. The amount of heat generated during the polymerization of 5.6 kg polyethylene is ............ Kcal. {(Round off to the nearest integer)}
The heat of polymerization of ethylene is 25 Kcal/mol. The amount of heat generated during the polymerization of 5.6 kg polyethylene is ............ Kcal. {(Round off to the nearest integer)}
Show Hint
The heat of polymerization is per mole of monomer. Always convert the mass to moles using the molar mass before multiplying by heat of reaction.
Updated On: Jan 30, 2026
Hide Solution
Verified By Collegedunia
Correct Answer: 4975
Solution and Explanation
We are given:
- Heat of polymerization = \( 25 \, {Kcal/mol} \)
- Mass of polyethylene = \( 5.6 \, {kg} = 5600 \, {g} \)
- Molar mass of polyethylene (monomer unit ethylene) = \( 28 \, {g/mol} \)
To find the total number of moles of ethylene polymerized: \[ {Moles of ethylene} = \frac{5600 \, {g}}{28 \, {g/mol}} = 200 \, {mol} \] Now calculate the total heat released: \[ {Heat} = 200 \, {mol} \times 25 \, {Kcal/mol} = 5000 \, {Kcal} \]
- Heat of polymerization = \( 25 \, {Kcal/mol} \)
- Mass of polyethylene = \( 5.6 \, {kg} = 5600 \, {g} \)
- Molar mass of polyethylene (monomer unit ethylene) = \( 28 \, {g/mol} \)
To find the total number of moles of ethylene polymerized: \[ {Moles of ethylene} = \frac{5600 \, {g}}{28 \, {g/mol}} = 200 \, {mol} \] Now calculate the total heat released: \[ {Heat} = 200 \, {mol} \times 25 \, {Kcal/mol} = 5000 \, {Kcal} \]
Was this answer helpful?
0
0
Top Questions on Polymer Science
- A rubber contains 70 wt% butadiene (molar mass = 54 g/mol), 20 wt% isoprene (molar mass = 68 g/mol), 5 wt% sulfur and 5 wt% carbon black. Assume that all the sulfur is present in crosslinks. If each sulfide crosslink contains an average of two sulfur atoms, the percentage of possible crosslinks that are joined by vulcanization is ............%. {(Round off to one decimal place)}
- GATE XE - 2025
- Polymer Science and Engineering
- Polymer Science
- A unidirectional composite of a resin is prepared with continuous fibers, wherein the volume fraction of the fiber in the composite is 0.7. Assume that the resin has a modulus of 9 GPa and the fiber has a modulus of 90 GPa. A sample of this composite, possessing a breadth of 4 mm and a thickness of 1 mm, is subjected to a uniaxial tensile test along the direction of the fiber.
Corresponding to a strain of 0.5%, the force applied on the sample is ............ N. {(Round off to the nearest integer)}- GATE XE - 2025
- Polymer Science and Engineering
- Polymer Science
- The density of an amorphous polymer is \(0.77 \, {g/cm}^3\) and that of its crystalline counterpart is \(0.99 \, {g/cm}^3\). The density of a semi-crystalline sample of this polymer is found to be \(0.88 \, {g/cm}^3\).
The degree of crystallinity (on weight basis) of this semi-crystalline sample is ............ {(Round off to two decimal places)}- GATE XE - 2025
- Polymer Science and Engineering
- Polymer Science
- Titration was used to determine the molar mass of two linear monodisperse polymers A and B. Both the polymers possess the same repeat unit and contain acid end-groups. First, 10 g of polymer A was titrated with 5 mL of a 0.1 M alkali solution. In a separate experiment, 5 g of polymer B was titrated with 5 mL of a 0.1 M alkali solution. All of the alkali solution reacted with the acid end-groups present in both polymer A and polymer B.\ The ratio of the molar mass of A to the molar mass of B is ............ {(Round off to one decimal place)}
- GATE XE - 2025
- Polymer Science and Engineering
- Polymer Science
- Buna-S is a polymer of:
View More Questions
Questions Asked in GATE XE exam
- A floating hot air balloon with volume 1000 m³ and gross mass (excluding the air in the balloon) 100 kg is in hydrostatic balance where the external air temperature is 10°C and density is 1 kg m³. The temperature of the air inside the balloon is ......... °C. (Round off to the nearest integer.) [Assume that the gas constant for dry air is 287 J K\(^{-1}\) kg\(^{-1}\).]
- GATE XE - 2025
- Atmospheric Science
- The solar constant for the Earth is 1368 W m\(^{-2}\). Consider the planet Jupiter whose mass is 320 times that of the Earth and distance from the Sun is 5.2 times that of the Earth. The solar constant for Jupiter is .......... W m\(^{-2}\). (Round off to the nearest integer.) [Assume the inverse square law for the solar radiation.]
- GATE XE - 2025
- Atmospheric Science
- In hot weather, a human body cools by the evaporation of sweat from its skin. The amount of water that must evaporate to cool the body by 1°C is .........% of the body mass. (Round off to two decimal places.) [Assume that latent heat of vaporization of water is \(2.25 \times 10^6 \, {J kg}^{-1}\) and specific heat capacities of both human body and liquid water are \(4.2 \times 10^3 \, {J K}^{-1} \, {kg}^{-1}\).]
- GATE XE - 2025
- Atmospheric Science
- The sensible heat (SH) flux at the locations P and Q are SH\(_P\) and SH\(_Q\), respectively. The value of \( \frac{SH_P}{SH_Q} \) is .......... (in integer).
- GATE XE - 2025
- Atmospheric Science
- A column of air mass extending from surface to a height of 10 km moving eastward along 30°N strikes a north-south oriented mountain range. While crossing the mountain range, the air mass acquires a relative vorticity of \( -3.65 \times 10^{-5} \, {s}^{-1} \) at the top. If the air mass maintains the same latitude and conserves potential vorticity, the height of the mountain range is ........ km. (Round off to the nearest integer.) [Assume the angular velocity of the Earth is \( 7.3 \times 10^{-5} \, {s}^{-1} \) and initial relative vorticity is zero.]
- GATE XE - 2025
- Atmospheric Science
View More Questions