Answer:
- 130.64°C.
Explanation:
- We can use the general law of ideal gas:<em> PV = nRT.</em>
where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
- If n and P are constant, and have two different values of V and T:
<em>V₁T₂ = V₂T₁</em>
<em></em>
V₁ = 634.0 L, T₁ = 21.0°C + 273 = 294.0 K.
V₂ = 307.0 L, T₂ = ??? K.
<em>∴ T₂ = V₂T₁/V₁ </em>= (307.0 L)(294.0 K)/(634.0 L) = <em>142.36 K.</em>
<em>∴ T₂(°C) = 142.36 K - 273 = - 130.64°C.</em>
Answer:
D
Explanation:
Firstly it is pertinent to know that, Electric force are due to the movement of electrons that is due to its gain and loss. This phenomenon is based on static electricity.
When the glass ruler is rubbed over the woolen sweater, the wool gets positively charged and the ruler gains electron to form negative charge.
Now if this charged is not earthed, the negative charged ruler attracts the uncharged bits of paper, as a result of which the paper gets attached to the ruler.
Answer: HBr has the lowest rate of effusion at a given temperature.
Explanation: The effusion rate usually increases with increase in temperature because the kinetic energy of the gaseous molecules increases. But it was not true for gases having heavier mass. This was explained by Graham's Law.
Graham's Law states that the rate of effusion of a gas is inversely proportional to the square root of its molecular weight.

We are given different gases with different Molecular masses. The gas having larger Molecular mass will have the lowest rate of effusion.
Mol. Mass of
= 80 g/mol
Mol. Mass of
= 16 g/mol
Mol. Mass of
= 17 g/mol
Mol. Mass of HBr = 81 g/mol
Mol. Mass of HCl = 36 g/mol
As, Mol. mass of HBr is the highest, so its rate of effusion will be the lowest.