Evening Guys, please I need help with this question below;
Lalasticlala,Seun,Mechanics96,Finestboy

iNewton:
Evening Guys, please I need help with this question below;
Lalastala,Sn,Mechans96,Fineoy

where exactly do you need help? here's my solution

LordeCalifornia:
where exactly do you need help? here's my solution

I thought one could only find mass when its in the 2phase liquid-vapour region?

iNewton:

I thought one could only find mass when its in the 2phase liquid-vapour region?

why do you think so? .
total mass remains constant(law of conservation of mass).
From the question, we can see that at the initial state, we had a superheated steam (the total mass at this state is the mass of the vapor alone)... when the steam was cooled passed saturation point ( now we have two phases) , the total mass becomes the summation of the mass of vapour and the mass of liquid.

but I'd still like to know why you "think" the mass would change at the superheated state.

LordeCalifornia:

why do you think so? .
total mass remains constant(law of conservation of mass).
From the question, we can see that at the initial state, we had a superheated steam (the total mass at this state is the mass of the vapor alone)... when the steam was cooled passed saturation point ( now we have two phases) , the total mass becomes the summation of the mass of vapour and the mass of liquid.

but I'd still like to know why you "think" the mass would change at the superheated state.

At the superheated state we have only Vapour, when we move to the two phase L-V region we have both Vapour and steam so I was of the opinion that we sum up the mass of vapour at superheated state+ mass of steam &Vapour at 2phaseL-V region. But you know this is not a constant Volume process ?
(Conservation of mass I.e mass at superheaated state=mass at 2phase L-V region ). How do you find the heat for the process and also what app did you use to solve the question?

iNewton:

At the superheated state we have only Vapour, when we move to the two phase L-V region we have both Vapour and steam so I was of the opinion that we sum up the mass of vapour at superheated state+ mass of steam &Vapour at 2phaseL-V region. But you know this is not a constant Volume process ?
(Conservation of mass I.e mass at superheaated state=mass at 2phase L-V region ). How do you find the heat for the process and also what app did you use to solve the question?

I understand what you're talking about. it'd be difficult for me to explain the concept online.
Just know that the mass of the vapour at superheated state is equal to the total mass of the system (whether constant volume or not)

I didn't use an app to solve it.
I solved it on paper, then arranged my solution using Microsoft Word because my handwriting is nothing to write home about

LordeCalifornia:

I understand what you're talking about. it'd be difficult for me to explain the concept online.
Just know that the mass of the vapour at superheated state is equal to the total mass of the system (whether constant volume or not)

I didn't use an app to solve it.
I solved it on paper, then arranged my solution using Microsoft Word because my handwriting is nothing to write home about

Thanks, I really appreciate!