# Ideal Gas Law Problem: Finding Pressure with Temperature Change and Fixed Mass

• TaraaaK
In summary, the conversation discusses how to calculate the pressure within a sealed sphere when the temperature is increased. The equation PV=nRT is used, but since the volume of the sphere is constant, the variable n can be ignored. The final equation used is P = (n(8314)(281)) / V, where n is the number of moles of gas and V is the volume of the sphere.
TaraaaK
does anyone know how to do this question. it feels like there's a part of the question missing as i don't know how to complete the equation

The pressure of a fixed mass of gas in a sealed sphere is measured to be 1.02 x 10^5 Pa at a temperature of 253K. Assuming the volume of the sphere doesn't change calculate the pressure within the sphere if the temperature is increased to 281K
(universal gas constant R =8314 J/K/mol

because it's a fixed mass of gas do i ignore n? when doing the equation

PV=nRT

## The Attempt at a Solution

(1.02 x 10^5) V = n (8314)(253)
1.02 x 10^5 V = 2103442n

TaraaaK said:
i don't know how to complete the equation
What equation are you trying to complete?

the first part first of all,but there are two unknown variables so I'm not sure what to do

i know i need to find the volume of the sphere for the first part but iam unsure of how to get a number for n

How are you going to use the volume of the sphere once you get it?

when i have the volume i will use it to find the pressure like so

P = (n(8314)(281)) / V

TaraaaK said:
when i have the volume i will use it to find the pressure like so
P = (n(8314)(281)) / V
TaraaaK said:
unsure of how to get a number for n
So, what all has changed besides temperature and pressure?

nothing

Correct.
TaraaaK said:
fixed mass of gas
TaraaaK said:
volume of the sphere doesn't change
Just because the equation uses two variables, does not mean you have to find values for both if they're both constant, and you're interested in solving for the value of some other variable.

Thank you so much
:)

## 1. What is the ideal gas law?

The ideal gas law is a fundamental law in thermodynamics that describes the relationship between the pressure, volume, and temperature of an ideal gas. It is expressed mathematically as PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is the temperature.

## 2. How do you solve an ideal gas law problem?

To solve an ideal gas law problem, you need to have at least three of the four variables (P, V, n, T) and use the ideal gas law equation to determine the missing variable. You may also need to convert units if they are not given in the same units as the gas constant (R = 0.0821 L∙atm/mol∙K).

## 3. What are the units for each variable in the ideal gas law?

The units for pressure (P) are usually in atm, mmHg, or kPa. Volume (V) is typically given in liters (L). The number of moles (n) has no units, while temperature (T) is typically given in Kelvin (K).

## 4. What are some common applications of the ideal gas law?

The ideal gas law is commonly used in various fields such as chemistry, physics, and engineering. It is used to calculate the volume of gas needed for a chemical reaction, determine the pressure in a gas container, and predict the behavior of gases in different environments. It is also used in the design and operation of engines, refrigerators, and other industrial processes.

## 5. What are the limitations of the ideal gas law?

The ideal gas law assumes that the gas particles have no volume and do not interact with each other. In reality, gas particles do have a small volume and may interact with each other, especially at high pressures and low temperatures. This means that the ideal gas law is only accurate for ideal gases, which do not exist in the real world. As a result, the ideal gas law is most accurate at low pressures and high temperatures.

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