A balloon contains helium gas expands from 230ml to 860 ml as more helium is added. What was the initial quantity of helium present if the expanded balloon contains 3.8x10^-4 mol, assuming constant temperature and pressure?

n₁ = 1.0× 10⁻⁴ mol

Explanation:

Given data:

Initial volume of balloon = 230 mL

Initial number of moles of He =?

Final number of moles of He = 3.8 × 10⁻⁴ mol

Final volume of balloon = 860 mL

Solution:

The given problem will be solve through Avogadro law,

"Number of moles of gas and volume are directly proportional to each other at constant temperature and constant pressure"

Mathematical relationship:

V₁/n₁ = V₂/n₂

No we will put the values.

230 mL  /n₁   = 860 mL/ 3.8 × 10⁻⁴ mol

n₁ = 230 mL× 3.8 × 10⁻⁴ mol/ 860 mL

n₁ = 874 × 10⁻⁴ mol. mL / 860 mL

n₁ = 1.0× 10⁻⁴ mol

a saline water is fed to a reverse osmosis unit at flow rate o rotameter connected to reject (retentate) line reads 8 installed in reject and permeate line reads 15.2 milli siemens/cm and 300 micro siemens/com respectively.