A gas stream contains 18.0 mole% hexane and the remainder nitrogen. The stream flows to a condenser, where its temperature is re
duced and some of the hexane is liquefied. The hexane mole fraction in the gas stream leaving the condenser is 0.0500. Liquid hexane condensate is recovered at a rate of 1.50 L/min. (a) What is the flow rate of the gas stream leaving the condenser in mol/min? (Hint : First calculate the molar flow rate of the condensate and note that the rates at which C6H14 and N2 enter the unit must equal the total rates at which they leave in the two exit streams.) (b) What percentage of the hexane entering the condenser is recovered as a liquid?
1 answer:
Answer:
A. 72.53 mol/min
B. 76.2%
Explanation:
Please check attachment to see the diagram of the components I drew.
I first converted flow rate to a molar flow rate. I got 11.5mol/ min after converting. Check attachment
A.) When we create a balance on all these components
n1 + n2 + n3
n1 = n2 + 11.5
Creating a balance on hexane
n1y1C6H14 = n2y2C6H14 + n3y3C6H14
n1(0.18) = n2(0.05) + 11.5mol/min(1.00)
When we put the first equation into the second one:
(n2+11.5mol/min)0.18 + n2(0.05) + 11.5mol/min(1.00)
= 0.18n2 + 2.07min/mol = 0.5n2 + 11.5mol/min
Collect like terms
0.18n2 - 0.05n2 = 11.5 - 2.07min/mol
= 0.13n2 = 9.43
n2 = 9.43/0.13
n2 = 72.53 mol/min
72.53 is the flow rate of the gas stream leaving the burner.
B.) n1 = n2 + 11.5mol/min
n1 = 72.53mol/min + 11.5mol/min
n1 = 84.93mol/min
Amount of hexane entering condenser
n1c6H14 = y1C6H14 = 0.18(84.03mol/min)
= 15.1mol/min
The percentage condensed
= (11.5mol/min)/(15.1mol/min) * 100
= 76.2% of hexane is recovered as liquid
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<h2>Corrected Question:</h2>
A step-up transformer has 26 turns on the primary coil and 720 turns on the secondary coil. If this transformer is to produce an output of 4100 V with a 16-mA current, what input current and voltage are needed?
<h2>Answer:</h2>The input current and voltage needed are 443 mA and 148 V respectively.
<h2>Explanation:</h2>In a step-up transformer, the relationship between the number of turns in its primary coil (), the number of turns in its secondary coil (
), the input voltage (
), the output voltage (
), the input current (
), and the output current (
) is given by;
=
=
This implies that;
=
---------------------(i)
=
---------------------(ii)
From the question;
= 26 turns
= 720 turns
= 4100V
= 16mA = 16 x 10⁻³A
(a) Substitute these values into equation (ii) as follows;
=
Solve for ;
= 720 x 16 x 10⁻³ / 26
= 443 x 10⁻³
= 443 mA
Therefore the input current needed is 443mA
(b) Also, substitute those values into equation (i) as follows;
=
Solve for ;
= 4100 x 26 / 720
= 148 V
Therefore, the input current needed is 148 V