Question

An unsteady-state system, with 6 liters as initial amount of water in the vessel, water flow in rate is 2 liters/ s and flow out rate is 4 liters/s, what will be the amount of water in the vessel after 1 second?

(a) 2 liters

(b) 4 liters

(c) 6 liters

(d) 8 liters

I have been asked this question during an internship interview.

Query is from Steady-State and Unsteady-State Systems in chapter Introduction to Material Balances of Basic Chemical Engineering

Answer 1

Correct choice is (b) 4 liters

For explanation: Total amount of water reduced from the vessel in 1 second = (4 – 2)*1 = 2 liters, => Final amount of water = 6 – 2 = 4 liters.