HI Muhammad,
I am a chemical engineer and currently working as a process engineer in one of the leading Indian MNC. Mass & Energy balance forms the part and parcel of chemical engineering discipline and it is also a part of my routine job. I can understand your situation and also your inquisitiveness to grasp the basic fundamentals, as this topic is the key to understanding chemical engineering.
I have in past done a couple of assignments relating to mass & energy balance and I can assure you that your problem will be solved.
Hoping to hear from you soon.
Thanks,
Raj Mehta