Question

experiment predicted outcome a 250 ml beaker is submerged in a large container of liquid a and turned upside down, and another 250 ml beaker is submerged and turned upside down in a large container of liquid b. hydrogen (h₂) gas is bubbled into each upside - down beaker until 100 ml of liquid has been displaced. the masses m_a and m_b of hydrogen inside each beaker is then chemically determined. note for advanced students: you may assume the solubility of h₂ in either liquid is very low. - m_a will be greater than m_b - m_a will be less than m_b - m_a will be equal to m_b - its impossible to predict whether m_a or m_b will be greater without more information. two 10 l glass flasks are evacuated and sealed. 10.0 ml of liquid a are injected through the seal into one flask, and 10.0 ml of liquid b are injected into the other flask. after 30 minutes, the pressures p_a and p_b inside the flasks are measured. - p_a will be greater than p_b - p_a will be less than p_b - p_a will be equal to p_b - its impossible to predict whether p_a or p_b will be greater without more information.

Explanation:

Step1: Analyze the first experiment

According to the ideal gas law \(PV = nRT\). Since the volume \(V\) of \(H_2\) displaced (\(100\space mL\)), temperature \(T\) (assumed same for both liquids as the experiment is done under same conditions), and gas constant \(R\) are the same. The pressure of \(H_2\) in each beaker is the same (because the external pressure from the liquid - gas interface is what determines the pressure of the gas inside the beaker for a given volume of gas at a given temperature). Using \(n=\frac{m}{M}\) (where \(M\) is the molar mass of \(H_2 = 2\space g/mol\)) and \(n=\frac{PV}{RT}\), since \(P\), \(V\), \(R\), \(T\) are same, \(n\) is same and thus \(m\) (mass of \(H_2\)) is same. So \(m_A=m_B\)

Step2: Analyze the second experiment

Vapor pressure is a property of a liquid that depends only on the nature of the liquid and the temperature. Since we have two different liquids (Liquid A and Liquid B), without knowing if they are the same liquid or not (e.g., if they are different substances with different intermolecular forces), we cannot predict the relationship between their vapor pressures. Vapor - pressure is determined by the strength of intermolecular forces in the liquid (e.g., for a liquid with stronger intermolecular forces, the vapor pressure is lower).

Answer:

For the first part: \(m_A\) will be equal to \(m_B\). For the second part: It's impossible to predict whether \(p_A\) or \(p_B\) will be greater without more information.