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4 years ago

Write the chemical equation of the polymerization reaction to synthesize PS

Engineering

1 answer:

marin [14]4 years ago

6 0

Explanation:

Styrene is a vinyl monomer in which there is a carbon carbon double bond.

The polymerization of the styrene, which is initiated by using a free radical which reacts with the styrene and the compound thus forms react again and again to form polystyrene (PS).

The equation is shown below as:

$\begin{matrix}& C_6H_5 \\&|\\n H_2C & =CH\end{matrix}$ ⇒ $\begin{matrix}&C_6H_5 \\&|\\ -[-H_2C & -CH-]-_n\end{matrix}$

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A piston–cylinder device contains 0.78 kg of nitrogen gas at 140 kPa and 37°C. The gas is now compressed slowly in a polytropic

DiKsa [7]

Answer:

The entropy change of nitrogen during this process. is - 0.32628 kJ/K.

Explanation:

Solution

Given that:

A piston cylinder device contains =0.78 kg of nitrogen gas

Temperature = 37°C

The nitrogen gas constant of R = 0.2968 kJ/kg.K

At room temperature cv = 0.743 kJ/kg.K

Now,

We assume that at specific condition the nitrogen can be treated as an ideal gas

Nitrogen has a constant volume specific heat at room temperature.

Thus,

From the polytropic relation, we have the following below:

T₂/T₁ =(V₁/V₂)^ n-1 which is,

T₂ = T₁ ((V₁/V₂)^ n-1

= (310 K) (2)^1.3-1 = 381.7 K

So,

The entropy change of nitrogen is computed as follows:

ΔSN₂ = m (cv₁ avg ln T₂/T₁ + ln V₂/V₁)

= (0.78) ((0.743 kJ/kg .K) ln 381.7 K/310K + (0.2968 kJ/kg. K) ln (0.5))

= 0.57954 * 0.2080 + (-0.2057)

= 0.12058 + (-0.2057) = -0.32628

Therefore the entropy change of nitrogen during this process. is - 0.32628 kJ/K.

6 0

3 years ago

X²-12x=0 ПЖ срочно реально решите помагие

nika2105 [10]

Answer:

формула pq sry i dont speak russian lol but thats the solution of the equation

4 0

3 years ago

Production of pressure vessels is fastening an open-ended cylinder and two rigid plates with bolts. The cylinder made of brass.

marysya [2.9K]

Answer:

The pressure that the container will start to leak is 154.87 psi

Explanation:

Force on end plates F = p(πR²) ⇒ pπR²

There is an equal reaction from four bolts ∴ F = pπR² / 4 .............. (1)

due to force on bolt, each bolt stretch by $\sigma_b$

Therefore; $\sigma_b = \frac{F_bL}{A_bE_b}$ .........................(2)

Leaking will start when tightening is outstretched by half turn per 16 turns per inch.

Cylinder experience a radial expansion as p increases. it is accompanied by poisson contraction $\sigma_c$ in axial direction. That is, the bolt do not have to experience a long stretch before the pressure breaks off the plate.

$\sigma_b + \sigma_c = \frac{1}{2} *\frac{1}{16} = \frac{1}{32}$ ...................... (3)

Axial deformation $\sigma_c$ of cylinder = L times axial ∈₀

<em>see continuation in attached picture in writing to get the value of Pressure: since we have the value of P</em>

R=8", L=16", t=0.125"

Area of bolts $A_b = \frac{\pi}{4}(\frac{7}{16})^2 = 0.150 inch^2$

$E_c = E_{cylinder} = 125$

$E_b = E_{bolt} = 200$

V for brass = 0.3

$P = \frac{1}{8*8*16} [\frac{0.150*12.5*200*0.125*10^9}{\pi*8*125*0.125+4*0.3*0.150*200}]$

p = 1.67797.183 P ⇒ 154.87 psi

7 0

4 years ago

The design for a new cementless hip implant is to be studied using an instrumented implant and a fixed simulated femur.

OlgaM077 [116]

Answer:

a) the velocity of the implant immediately after impact is 20 m/s

b) the average resistance of the implant is 40000 N

Explanation:

a) The impulse momentum is:

mv1 + ∑Imp(1---->2) = mv2

According the exercise:

v1=0

∑Imp(1---->2) = F(t2-t1)

m=0.2 kg

Replacing:

$0+F(t_{2} -t_{1} )=0.2v_{2}$

if F=2 kN and t2-t1=2x10^-3 s. Replacing

$0+2x10^{-3} (2x10^{-3} )=0.2v_{2} \\v_{2} =\frac{4}{0.2} =20m/s$

b) Work and energy in the system is:

T2 - U(2----->3) = T3

where T2 and T3 are the kinetic energy and U(2----->3) is the work.

$T_{2} =\frac{1}{2} mv_{2}^{2} \\T_{3} =0\\U_{2---3} =-F_{res} x$

Replacing:

$\frac{1}{2} *0.2*20^{2} -F_{res} *0.001=0\\F_{res} =40000N$

3 0

3 years ago

The technique of using guidelines and reference points

inysia [295]

Answer:

Linear perspective.

Explanation:

The technique of using guidelines and reference points to create a realistic sense (illusion) of depth in a two-dimensional artwork is called linear perspective.

In linear perspective, the realistic sense (illusion) of depth is typically created or done on a flat surface so that all the orthogonal or parallel lines can converge at a single vanish point of the drawing's horizon line. Thus, this technique make drawings or paintings of objects to look real.

Hence, linear perspective comprises of three (3) basic components and these are;

1. Vanishing point.

2. Horizon line.

3. Orthogonal or parallel lines.

Generally, drawings (objects) that are drawn or created using linear perspective appear to be larger when viewed closely while drawings (objects) that are further away, appear to be small.

3 0

3 years ago