Explanation

• When equal masses of methane (CH4) and oxygen (O2) are mixed, the number of moles of each gas is equal. Since the molar mass of methane (16 g/mol) is smaller than that of oxygen (32 g/mol), the number of molecules of methane is greater than the number of molecules of oxygen.
• Let's calculate the fraction of total pressure exerted by oxygen:
• Number of moles of methane = Number of moles of oxygen (since equal masses are mixed)
• Molar ratio of methane to oxygen = 1:1
• Total pressure = Partial pressure of methane + Partial pressure of oxygen = 1 (due to methane) + 1 (due to oxygen) = 2
• Fraction of total pressure exerted by oxygen = Partial pressure of oxygen / Total pressure = 1 / 2 = 2/3

Explanation

• In a sample of a substance, the particles (atoms or molecules) have a distribution of energies at any given temperature. This is known as the Maxwell-Boltzmann distribution.
• According to this distribution, some particles have high energies, while others have low energies, but the average energy of the particles is constant at a given temperature.
• The energy of individual particles in a sample is not the same, as they are in constant motion and colliding with each other, leading to a range of energies.
• This is why the concept of average energy or kinetic energy is used to describe the energy of a sample as a whole.

Explanation

Isotopes are atoms of the same element that have the same number of protons (atomic number) but a different number of neutrons. This means they have:

• Same chemical properties (because they have the same number of protons, which determines chemical behavior)
• Different mass numbers (because they have a different number of neutrons)
• Different physical properties (such as different atomic masses, different radioactivity, etc.)

Explanation

• The compound K2Cr2O7 (potassium dichromate) is not a transition metal complex.
• It contains chromium in the +6 oxidation state, but it does not form a coordination complex with ligands.
• Instead, it is a chromium compound in which chromium is in the form of a polyatomic ion

Explanation

The pair of liquids that does not obey Raoult's Law is propanol and propanone.

Explanation

Among the halogen acids (HF, HCl, HBr, and HI), HI (hydroiodic acid) is the strongest.

The strength of an acid is determined by the ease with which it can donate a hydrogen ion (H+).

The H-I bond is the weakest of the halogen acid bonds, allowing HI to readily dissociate in water and release H+ ions. 

Explanation

The chemical analysis in which all the elements present in a compound are identified is called qualitative chemical analysis.

This type of analysis focuses on determining the presence or absence of specific elements or compounds within a sample, rather than quantifying their amounts. 

Explanation

A solid changes directly into a gas without becoming liquid

Example: Camphor, dry ice (solid CO₂), and iodine undergo sublimation.

Explanation

• Phenolphthalein is a pH indicator that changes color in response to changes in acidity or basicity.
• In an acidic medium, it is colorless, and in a basic medium, it turns pink.

Explanation

• Osmosis is the process where a solvent, typically water.
• It moves through a porous membrane from an area of lower solute concentration to an area of higher solute concentration.