Matter, Atoms and Molecules RRB PYQ

To find the partial pressure of N2 gas, we can use Dalton's Law of Partial Pressures, which states that the partial pressure of a gas is the ratio of its moles to the total moles multiplied by the total pressure. Total Moles: n_total = 0.2 moles O2 + 0.4 moles N2 + 0.1 moles NH3 + 0.3 moles He = 1.0 moles. Partial Pressure of N2 = (n_N2 / n_total) x P_total = (0.4/1.0) x 1 atm = 0.4 atm. Thus, the partial pressure exerted by N2 gas is 0.4 atm.

To find the number of iron atoms in a piece of iron weighing 2.8 g, follow these steps: Molar mass of iron (Fe) = 56 g/mol. Avogadro's number = 6.022x10^23 atoms/mol. Number of moles of iron = 2.8g / 56g/mol = 0.05 mol. Number of atoms = 0.05 mol x 6.022x10^23 atoms/mol = 3.011x10^22 atoms. Thus, the number of iron atoms in a 2.8 g piece of iron is 3.011x10^22 atoms.

Diffusion is the spontaneous movement of particles from an area of high concentration to an area of low concentration. It is a fundamental process in both biological and chemical systems. Factors like temperature and particle size can affect the rate of diffusion. This process does not require energy, unlike active transport.

The element with the electronic configuration 2,8,5 is Phosphorus. Phosphorus has 15 electrons, distributed as 2 in the first shell, 8 in the second, and 5 in the third. It is essential for biological molecules like DNA and ATP.

Cobalt – Co, Copper – Cu, Sulphur – S, Sodium – Na. Matching these gives 1-B, 2-D, 3-A, 4-C.

Atoms of different elements have distinct properties and are not identical. Atoms are the smallest units of matter, consisting of protons, neutrons, and electrons. John Dalton's atomic theory, proposed in the early 19th century, laid the foundation for our understanding of atomic structure.

In calcium oxide (CaO), the ratio of calcium (Ca) to oxygen (O) by mass is 5:2. This is derived from their atomic masses: calcium has an atomic mass of 40u, and oxygen has an atomic mass of 16u. Therefore, the mass ratio is calculated as 40:16, which simplifies to 5:2.

The total number of neutrons in dipositive zinc ion with mass number 70. No. of neutrons = Mass number - Atomic number. Mass number of zinc = 70, Atomic number of zinc = 30. Thus, number of neutrons = 70 - 30 = 40.

A double displacement reaction occurs when two compounds exchange ions to form two new compounds. In this case, HCl and KOH exchange ions to form KCl and H2O. This type of reaction typically results in the formation of a precipitate, water, or gas.

Statement A: Increasing temperature and pressure can liquefy atmospheric gases by bringing molecules closer together. Statement B: On a hot, dry day, high temperature and low humidity increase the rate of evaporation, leading to significant cooling. So, both statements are true.