Standard states: A pressure of 1 atm and a constant temperature (25˚C) are taken as standard states. State Standard states Gas Ideal gas at the given temperature and 1 atm Liquid Pure liquid at the given temperature and 1 atm Solid Stable crystalline from at given temperature and 1 atm pressure Heat of reaction: Heat Read more about Enthalpy change, (Δr H) of reactions – reaction Enthalpy[…]
Theorem of Parallel Axes: This theorem states that the moment of inertia I of a body about any axis is equal to its moment of inertia about a parallel axis through its centre of mass, plus the product of the mass M of the body and the square of the perpendicular distance a between the Read more about Theorems of Parallel and Perpendicular Axes[…]
Enthalpy or Heat of Combustion: It is the amount of heat evolved or decreased in enthalpy when one mole of a substance is completely oxidized. Organic compounds containing only carbon, hydrogen, and oxygen are burnt to gaseous carbon dioxide and liquid water. For example, C2H6(g) + 3.5O2(g) → 2CO2(g) + 3H2O(l); ΔH = − 372.8 kcal Read more about Enthalpies of different Reactions[…]
Statement: “Energy can neither be created nor be destroyed. But it can be converted from one form of energy into another form of energy.” When a system changes for a given initial state to a given final state, both the work W and Q depend on the nature of the process. Experimentally, however, we find a Read more about The first law of thermodynamics[…]
1. Combination reactions: A + B → C For such a reaction to be redox reaction, either A or B or both should be in elemental form. Ex: 2 C⁺²O⁻²₂ (g) + O0₂ (g) → 2 C⁺⁴ O⁻²₂ (g) Fe0 (s) + S0 (s) → Fe⁺²S⁻² (s) 2. Decomposition reactions: Breakdown of a compound to form 2 Read more about Types of Redox Reaction[…]
In a rocket, the fuel burns and produces gases at high temperatures. These gases are ejected out of the rocket from a nozzle at backside of the rocket. The ejecting gas exerts a forward force on the rocket which helps it in accelerating.Suppose, a rocket together with its fuel has a mass M0 at t Read more about Rocket Propulsion[…]
It denotes the oxidation state of an element in a compound Rules to assign Oxidation number: Elements in free state have zero oxidation number.Ex: H2, O2, N2, C etc. have 0 oxidation number For ions composed of only one atom, the charge on the ion is its oxidation number. Ex: Cl– → -1 oxidation number Mg2+ → Read more about Oxidation Number Concept[…]
When a body moves along a straight line, then the product of the, mass m and the linear velocity of the body is called the “linear momentum” p of the body (p = m*v), if a body is rotating about an axis, then the sum of the moments of the linear momenta of all the Read more about Relation between Angular Momentum and Moment of inertia[…]
1. Law of conservation of mass: Given by Lavoisier: “In all chemical changes, the total mass of the system remains constant.”i.e., Matter can neither be created nor destroyed. Ex: 2H2 + O2 = 2H2O. Reactants mass = 4 + 32 = 36 g. Products mass = 2 X (2 + 16) = 36 g. Reactants mass Read more about Laws of chemical combinations[…]
Projectile motion is a form of motion in which an object or particle (called a projectile) is thrown near the earth’s surface, and it moves along a curved path under the action of gravity only.Motion along Horizontal direction: A body projected from the ground with a velocity u at an angel with the horizontal. Horizontal components of the velocity Read more about Projectile motion[…]