Pressure in a gas container measured with a barometer and a U pipe

[Callmelucky]

Homework Statement

to a container filled with gas, U shaped pipe is attached, as shown in the picture(picture below). What is a gas pressure in the container if the height of the pillar of mercury in barometer is 740 mm?

Relevant Equations

pressure = density * g * height

Can someone please tell me where I am wrong, here goes the question:

to a container filled with gas, U shaped pipe is attached, as shown in the picture(picture below). What is a gas pressure in the container if the height of the pillar of mercury in barometer is 740 mm?

The way I solved it is: pressure of mercury(740mm) + 5 cm difference in U pipe --> 0.740 m * 13600 * 9.81 + 0.05 * 13600 * 9.81 = 105398.64 Pa. But the answer at the and of the textbook is 100 062 Pa.

Thank you.

 

[BvU]

Any chance the textbook is wrong ?

I find somewhat different conversion factors, but with three digit accuracy the 105 kPa stands firmly.
mm Hg to Pa
density of Hg

(you can't find a seven digit result from a three digit factor)

 

[Callmelucky]

it seems that this textbook is full of flaws.
Can you check my previous post(from an hour ago or so), I think my answer is correct and their wrong on that one too.

Thank you for answering

 

[erobz]

Where is the 740 mm height of mercury? Oh, never mind. It's in a barometer that is not shown.

 

[Callmelucky]

Where is the 740 mm height of mercury? Oh, never mind. It's in a barometer that is not shown.

That is another thing, if it's gas, I guess that container couldn't be filled on normal pressure(atm), so I don't understand what does pressure outside container(thoose 740 mm Hg) has to do with pressure inside of gas?

 

[BvU]

The U tube links the outside world with the inside of the container. Ask yourself what happens to the 5 cm if the ambient pressure changes.

 

[Callmelucky]

The U tube links the outside world with the inside of the container. Ask yourself what happens to the 5 cm if the ambient pressure changes.

thanks, that makes sense.