Solving a Take Home Quiz: Determining Gas Density

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SUMMARY

The discussion centers on calculating the new density of helium gas when its temperature is raised from 0°C to 100°C at constant pressure. The initial density of helium is given as 0.179 kg/m³. Participants clarify that since the mass remains constant, the change in density can be derived from the ideal gas law, specifically using the relationship between volume and temperature. The key takeaway is that the density formula can be integrated into the ideal gas equation, allowing for the calculation of new density without needing explicit mass or volume values.

PREREQUISITES
  • Understanding of the ideal gas law (P1V1/T1 = P2V2/T2)
  • Knowledge of density calculation (density = mass/volume)
  • Familiarity with temperature conversion (Celsius to Kelvin)
  • Basic algebra skills for manipulating equations
NEXT STEPS
  • Study the ideal gas law and its applications in thermodynamics
  • Learn about the relationship between temperature and volume in gases
  • Explore density changes in gases under varying temperature and pressure conditions
  • Practice problems involving the calculation of gas densities using the ideal gas law
USEFUL FOR

Students studying chemistry or physics, particularly those focusing on gas laws and thermodynamics, as well as educators looking for problem-solving strategies in gas density calculations.

Cheapo2004
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Heres a problem on a take home quiz I am doing, but i can't figure out how to get past the first step?!

The density of helium gas at 0°C is 0.179 kg/m^3. The temperature is then raised to 100°C, but the pressure is kept constant. Assuming that Helium is an ideal gas, calculate the new density of the gas.

Heres the equations i have:
P1V1 / T1 = P2V2 / T2

In order to work this equation i need volume, but i have a density, here's the equation i think i need:

roe = m / V
(density = mass / volume)

How do i work this if i don't have mass or volume?!
 
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Cheapo2004 said:
Heres a problem on a take home quiz I am doing, but i can't figure out how to get past the first step?!

The density of helium gas at 0°C is 0.179 kg/m^3. The temperature is then raised to 100°C, but the pressure is kept constant. Assuming that Helium is an ideal gas, calculate the new density of the gas.

Heres the equations i have:
P1V1 / T1 = P2V2 / T2

In order to work this equation i need volume, but i have a density, here's the equation i think i need:

roe = m / V
(density = mass / volume)

How do i work this if i don't have mass or volume?!
You have to find the proportional increase in volume: V2/V1. You know P1 and P2 (they are the same. You know T1 and T2. All you have to find is V2/V1.

AM
 
You know the mass of the gas doesn't change. Try putting the density formula into the equation, you will find that they cancel out.
 

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