Change in Pressure: Find Gas P (Pa) Experiment

In summary, the experiment aims to determine the specific heat of a gas by using a water manometer attached to a flask. The change in pressure of the gas is calculated by using the equation ΔP = ρgΔh, where ρ is the density of the fluid, g is the acceleration due to gravity, and Δh is the difference in water level. However, in the attempt at a solution, the incorrect value of atmospheric pressure was used, resulting in an incorrect calculation. Paying attention to units is crucial in avoiding errors.
  • #1
Devin Longo
11
0

Homework Statement



An experiment to determine the specific heat of a gas makes use of a water manometer attached to a flask (the figure below ). Initially the two columns of water are even. Atmospheric pressure is 1.5 105 Pa. After heating the gas, the water levels change to those shown. Find the change in pressure of the gas in Pa.



2. Homework Equations
[tex]\Delta[/tex]P = [tex]\rho[/tex]g[tex]\Delta[/tex]h



The Attempt at a Solution



I basically did 1.5 x 10 ^5 * 9.8 m/s2 * .01m (what I assume given the picture to be the change in height)
 

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  • #2
Difference in water level is 4 cm.
So ΔP = ρgΔh.
 
  • #3
If I change 4 cm to meters I get 58800 as the calculated total from the equation, which is incorrect according to the website. Is there some factor I'm neglecting?
 
  • #4
Devin Longo said:
If I change 4 cm to meters I get 58800 as the calculated total from the equation, which is incorrect according to the website. Is there some factor I'm neglecting?

Rho is the density of the fluid, not the pressure, so I'm not sure why you are using 1.5e5 in the equation. Also, pay attention to units when you are doing your computation (doing so would have revealed this error).
 

Related to Change in Pressure: Find Gas P (Pa) Experiment

1. How does pressure affect gas?

Pressure and gas are directly proportional - as pressure increases, the volume of gas decreases, and vice versa. This is known as Boyle's Law.

2. Can pressure be measured?

Yes, pressure can be measured using a variety of tools such as barometers, manometers, and pressure sensors. In this experiment, we will be using a manometer to measure the pressure of the gas.

3. What is the unit of measurement for pressure?

The SI unit for pressure is Pascal (Pa), named after the French mathematician, Blaise Pascal. Other commonly used units include atmospheres (atm), millimeters of mercury (mmHg), and pounds per square inch (psi).

4. How can I calculate pressure using the gas law equation?

The gas law equation, PV=nRT, can be rearranged to solve for pressure (P), which is equal to the number of moles (n) of gas multiplied by the gas constant (R) and the temperature (T) in Kelvin, divided by the volume (V) of gas. So, P=nRT/V.

5. What factors can cause a change in pressure in a gas?

Changes in temperature, volume, and number of moles of gas can all affect the pressure of a gas. Additionally, external factors such as altitude, gravity, and the presence of other gases can also impact the pressure of a gas.

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