Q1)
we can use the ideal gas law equation to find the total pressure of the system ;
PV = nRT
where P - pressure
V - volume - 7 x 10⁻³ m³
n - number of moles
total number of moles - 0.477 + 0.265 + 0.115 = 0.857 mol
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature in K - 273 + 25 °C = 298 K
substituting the values in the equation
P x 7 x 10⁻³ m³ = 0.857 mol x 8.314 Jmol⁻¹K⁻¹ x 298 K
P = 303.33 kPa
1 atm = 101.325 kPa
Therefore total pressure - 303.33 kPa / 101.325 kPa/atm = 2.99 atm
Q2)
partial pressure is the pressure exerted by the individual gases in the mixture.
partial pressure for each gas can be calculated by multiplying the total pressure by mole fraction of the individual gas.
total number of moles - 0.477 + 0.265 + 0.115 = 0.857 mol
mole fraction of He -

mole fraction of Ne -

mole fraction of Ar -

partial pressure - total pressure x mole fraction
partial pressure of He - 2.99 atm x 0.557 = 1.67 atm
partial pressure of Ne - 2.99 atm x 0.309 = 0.924 atm
partial pressure of Ar - 2.99 atm x 0.134 = 0.401 atm
The eight-element periodicity found in the Periodic Table is related to the number of electrons in the outermost energy level of the atoms that make up each element
this statement is true
Answer:
470 °C
Explanation:
This looks like a case where we can use Charles’ Law:

Data:
V₁ = 20 L; T₁ = 100 °C
V₂ = 40 L; T₂ = ?
Calculations:
(a) Convert the temperature to kelvins
T₁ = (100 + 273.15) K = 373.15 K
(b) Calculate the new temperature

Note: The answer can have only two significant figures because that is all you gave for the volumes.
(c) Convert the temperature to Celsius
T₂ = (750 – 273.15) °C = 470 °C