Need help with questions 1 & 2 below parts a & b for both. Please show your work

Question

Need help with questions 1 & 2 below parts a & b for both. Please show your work. I would greatly appreciate your help! Thank you!

1. A column of mercury is 4.00 mm in diameter and 20.0 cm high. a) Calculate the mass of mercury in lbm. al 3 volume mas s b) Calculate the gauge pressure at the bottom of the column of mercury in psi. 2, A fuel mixture contains 40% n-hexane, 10% n-heptane and 50% n-octane on a mass basis. mo a. Calculate the average molecule weight. n-heptane- 100. 2 a 1 mel 0.684 n-octane .22 ginal-, 0.103 b. If the feed rate of this mixture to a burner is 100 Ibmol/h, what is the molar flowrate of the n-hexane (in lbmol/h)?

Explanation / Answer

1)

a)

Given, Diameter of the column = 4.0 mm = 0.004m

Height of the column = 20.0 cm = 0.20 m

Density of the mercury = 13.55X103 kg/m3  

And we know that ,

Volume of the cylinder or column = V=r2h = V= d2h/4

therefore, volume of the mercury = V =(* 0.0042* 0.20)/4 = 2.513 *10-6 m3

Now, Density = mass /volume ==> mass = density * Volume = (13.55*103 )* (2.513 *10-6)

= 0.03405 kg

==> mass of mercury = 0.03405 Kg = 34.05 g.

b)

gauge pressure = density X acceleration due to gravity X height of mercury column

= (13.55*103 ) X 9.8 m/s2 X 0.20

= 26558 kg/(ms2 ) = 26558 pa

Now, 6897 pa is equal to 1 psi

==> 26558 pa ------> (1/6897) * 26558 = 3.85 psi

Therefore, Gauge Pressure = 3.85 psi.

2)

a)

Given mass composition as 40% n-hexane

10% n- heptane

50% n-octane

since above are mass compositions,

so we can calculate average molecular weight of the composition as

= ( 0.40* molecular weight of n-hexane) + ( 0.10 * molecular weight 0f n-hepatane) + ( 0.50 * molecular weight of n- octane)

=( 0.40 * 86.17) +( 0.10* 100.2) + ( 0.50* 114.22)

= 101.590 g /mol

Therefore, average molecular weight of the compound = 101.590 g/mol

b)

Basis : Flow rate of mixture = 100 lbmass/h

so , flow rate of n-hexane = 40 lbmass/h

now , moles of n-hexane = weight of n-hexane / molar mass of n-hexane

= 40 (lbmass/hr) / 86.17 (lbmass/lbmol) = 0.4641 lbmol/hr

Therefore, flow rate of n-hexane = 0.4641 lbmol/hr

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