Engineering College

The atomic weights of C and H are 12 and 1, respectively. The chemical formula of polyethylene is (C2H4)n. The number average mean molecular weight of polyethylene with a degree of polymerization of 12,000 is:_____.
a. 120,000.
b. 336,000.
c. 280,000.
d. 296,000.

Answers

Answer 1

Answer:

b. 336,000.

Explanation:

Step 1: Calculate the molecular weight of the monomer

Polyethilene is a polymer with the formula (C₂H₄)ₙ, where C₂H₄ is the monomer and n is the number of monomers in the polymer. We can calculate the molecular weight of the monomer by addition of the weights of the atoms that form it.

MC₂H₄ = 2 × MC + 4 × MH

MC₂H₄ = 2 × 12 + 4 × 1 = 28

Step 2: Calculate the average molecular weight of polyethylene

The average degree of polymerization (DP) of polyethylene is 12,000. We can calculate the average molecular weight of polyethylene using the following expression.

DP = M(C₂H₄)ₙ/MC₂H₄

M(C₂H₄)ₙ = DP × MC₂H₄

M(C₂H₄)ₙ = 12,000 × 28 = 336,000

Related Questions

A fuel oil is burned with air in a furnace. The combustion produces 813 kW of thermal energy, of which 65% is transferred as heat to boiler tubes that pass through the furnace. The combustion products pass from the furnace to a stack at 6500C. Water enters the boiler tubes as a liquid at 200C and leaves the tubes as saturated steam at 20 bar absolute. Calculate the rate (kg/h) at which steam is produced.

Answers

The rate at which steam is produced is equal to 701 kg/hour.

What is a Boiler?

A Boiler may be characterized as a type of device or instrument that significantly transforms water into steam. There are two types of boiler are found. They are water tube boilers and fire tube boilers.

According to the question,

The power generated by combustion, W = 813kW.

The efficiency of the boiler, η = 65% = 0.65.

Temperature, To = 650°C.

Water enters the boiler tubes as a liquid, T1 = 20°C.

Water leaves the tubes as saturated steam, P2 = 20 bar.

The enthalpy of water at 20°C, [tex]h_1[/tex] = 83.9kJ/kg.

The enthalpy of water at 20 bar pressure, [tex]h_2[/tex] = 2797.29kJ/kg.

Enthalpy change can be calculated by ΔH = [tex]h_2-h_1[/tex]

= 2797.29kJ/kg - 83.9kJ/kg = 2713.3 kJ/kg.

The total energy that can be developed can be calculated by the formula:

Q = W × η = 813 × 0.65 = 528.45 kW.

The mass of the flow rate of the rate at which steam is produced is calculated by the following formula:

[tex]m^.[/tex] = Q/ΔH

             = 528.45 kW/2713.3 kJ/kg.

             = [tex]\frac{528.45kW }{2713.3kJ/kg} *\frac{3600kJ/h}{1kW}[/tex] = 701 kg/hour.

Therefore, the rate at which steam is produced is equal to 701 kg/hour.

To learn more about Boilers, refer to the link:

https://brainly.com/question/15421700

#SPJ1

A piece of corroded steel plate was found in a submerged ocean vessel. It was estimated that the original area of the plate was 5 in.2 and that approximately 2.3 kg had corroded away during the submersion. Assuming a corrosion penetration rate of 200 mpy for this alloy in seawater, estimate the time of submersion in years. The density of steel is 7.9 g/cm3.

Answers

Answer:

the estimated time of submersion is 17.7 years

Explanation:

Given the data in the question;

estimate the time of submersion in years.

we write down the relation between time of submersion and corrosion penetration as follows;

CPR(mpy) = K × W(mg) / [ A(in²) × p(g/cm³) × t(hr) ]

we solve for t

t = (K × W) / ( AP × CPR )

given that;  

Area A = 5 in²

W = 2.3 kg = 2.3 × 10⁶ mg

density of steel p = 7.9 g/cm³

CPR = 200

we know that K is 534

so we substitute

t = (534 × 2.3 × 10⁶ mg) / ( 5 in² × 7.9 g/cm³ × 200 mpy )

t = 1,228,200,000 / 7900

t = 155468.3544 hr

t = 155468.3544 hr × ( 1 yrs / ( 365 × 24 hrs )

t = 17.7 years

Therefore, the  estimated time of submersion is 17.7 years

The 150 mm thick wall of a gas fired furnace is constructed of fireclay brick (k=1.5 W/m.K) , tho=2600 kg/m3, and cp=1000 J/kg.K ) and is well insulated at its outer surface. The wall is at a uniform initial temperature of 20 degree C, when the burners are fired and inner surface is exposed to products of combustion for which T infinity=950 degree C and h=100 W/ m2.K.
(A) How long does it take for the outer surface of the wall to reach a temperature of 750 degree C?
(B) plot the temperature distribution in the wall at the foregoing time.

Answers

Answer:

I am thick but I dont know the anwser

The time that it will take for the outer surface of the wall to reach a temperature of 750 degree C will be 33800 seconds.

How to calculate the time?

Using the approximation methods, Fo will be;

= In(0.215/1.262)/(1.4289)²

= 0.867

Then, the time taken will be:

= 0.867(0.15)²/(1.5/2600 × 1000)

= 33800 seconds.

In conclusion, the time taken is 33800 seconds.

Learn more about time on:

https://brainly.com/question/10428039

#SPJ2

Other Questions
Energy in a vacuum travels by ___.A. radiationB. conductionC. convection Hi I struggling with this can someone help me pls. find the angles of a cyclic quadrilateral ABCD in Angle A = (4x+20 )^0 , Angle B = (3x+5 )^0 , Angle C =(4y)^0 , Angle D = (7y-5)^0 Sunland Company reports the following operating results for the month of August: sales $300,000 (units 5,000); variable costs $223,000; and fixed costs $70,800. Management is considering the following independent courses of action to increase net income. Compute the net income to be earned under each alternative. 1. Increase selling price by 10% with no change in total variable costs or sales volume. Net income $enter a net income if the selling price is increased by 10% 2. Reduce variable costs to 56% of sales. Net income $enter a net income if the variable costs are reduced to 56% of sales 3. Reduce fixed costs by $18,000. Net income $enter a net income if the fixed costs are reduced by $18,000 What was the SILK ROAD and what was its effect upon the Chinese economy? ASAP. Which process represents a physical change?1.Roasting a marshmallow over a camp fire2.Melting chocolate in a pan on the stove3.Bruising of a banana's skin after dropping on the floor4.Bubbling due to an antacid tablet in vinegar Taking the convection heat transfer coefficient on both sides of the plate to be 860 W/m2 K, deter- mine the temperature of the sheet metal when it leaves the oil bath. Also, determine the required rate of heat removal from the oil to keep its temperature constant at 45C. The vertex of f(x) is (2, - 3) . is the vertex of f(x) + 3 how do the conditions in tube c prevent air reaching the iron nail Please help.See pic attachedWINNER GETS BRAINLIEST, THANKS AND A STAR RATING-EXCELLENTAlso please friend request me and I'll accept it.Thanks xx Drag each item to the appropriate space on the proof. whose power is increased by the department of homeland security ? Evaluate: 2x-5y for x=-7 and y=-2 In which 5 elections of the past did the winner of the popular vote fail to win the electoral vote for the presidency? The teacher uses this thing a lot. Ela Ben invests $4300 in two different accounts. The first account paid 7%, the second account paid 4% in interest. At the end of the year he had earned $247 in interest. How much was in each account? Why did Bush propose legislation to help the savings and loan industry?to create new types of banksBto end an economic crisis created by failing banksto help pay down the federal debt created by overspending Im officially about to lose it Riley took 5 tests in science. Each test had a different score. The mean score of the tests was 90%. The median score of the tests was 85%. Based on this information, select the two statements that must be true. A: More than half of the scores were 85% or greater.B: More than half of the scores were 90% or greater.C: There were no scores less than 85% D: There were no scores less than 90% E: At least one score was exactly 85% F: At least one score was exactly 90% I need a step by step explanation but Id be ok with the solution.