Some Basic Concepts of Chemistry | Class 11 Chemistry Formulas Sheet | Revision List CBSE NCERT

Summary

In this engaging video, the host provides a comprehensive revision of essential chemistry formulas for Class 11. Covering topics like density, temperature conversions, atomic mass, molecular mass, molar calculations, and more, the video breaks down complex concepts into easy-to-understand explanations. The host emphasizes a quick and efficient approach to mastering key formulas, offering tips and tricks to help students retain information. With a focus on practical applications, this session ensures viewers can confidently apply these formulas to solve real-world chemistry problems.

Takeaways

• 😀 The video is part of a free learning platform where you can study Physics, Chemistry, Maths, and Biology, all for free.
• 😀 The main focus of the lesson is on the basic concepts and formulas of Chemistry, particularly for Class 11 students.
• 😀 The formula for density is explained as mass/volume, with an emphasis on using grams per centimeter cube (g/cm³) rather than kilograms per meter cube.
• 😀 A simple trick is shared for converting temperatures between Celsius, Kelvin, and Fahrenheit.
• 😀 Important formulas for converting Celsius to Kelvin and Fahrenheit are: Kelvin = 273.15 + Celsius and Fahrenheit = 32 + (9/5) × Celsius.
• 😀 The atomic mass of an element can be used to calculate the mass of one atom by dividing by Avogadro's number.
• 😀 A formula for calculating the average atomic mass of an element based on isotopic abundances is provided.
• 😀 The molecular mass formula is given as the sum of (X1 × A1) + (X2 × A2), where X1, X2 are the number of atoms and A1, A2 are the atomic masses of different elements in a molecule.
• 😀 A new formula for calculating empirical formula factor is introduced, with an example using molecular and empirical formula mass.
• 😀 A variety of formulas are discussed, such as those for molar mass, concentration, mole fraction, and molarity, which are essential in solving common chemistry problems.

Q & A

What is the formula for density?

Density is given by the formula: Density = Mass / Volume. It is important to note that the units for mass are usually in grams and volume in cubic centimeters (cm³) or liters.

How do we convert temperature from Celsius to Kelvin and Fahrenheit?

To convert Celsius to Kelvin, use the formula: Kelvin = Celsius + 273.15. To convert Celsius to Fahrenheit, use the formula: Fahrenheit = (Celsius × 9/5) + 32.

What is the method to calculate the average atomic mass of an element using isotopes?

To calculate the average atomic mass of an element with isotopes, use the formula: (R1/100 × A1) + (R2/100 × A2) + ... where R1 and R2 are the relative abundances, and A1 and A2 are the atomic masses of the isotopes.

How is the molecular mass of a compound calculated?

The molecular mass of a compound is calculated by adding the atomic masses of all the atoms in the molecule. For example, in ammonia (NH₃), the molecular mass is 1×14 (for nitrogen) + 3×1 (for hydrogen), which equals 17 g/mol.

How do you calculate the number of moles in a substance?

The number of moles is calculated by dividing the mass of the substance by its molar mass. The formula is: Number of moles = Mass / Molar mass.

What is the formula for calculating mass percent of an element in a compound?

The mass percent of an element in a compound is calculated using the formula: Mass percent = (Mass of the element / Molar mass of the compound) × 100.

What is the empirical formula factor and how is it calculated?

The empirical formula factor is calculated by dividing the molar mass of the compound by the empirical formula mass. The formula is: Empirical formula factor = Molar mass / Empirical formula mass.

How do you calculate the molar concentration (molarity) of a solution?

Molarity (M) is calculated by dividing the number of moles of solute by the volume of solution in liters. The formula is: Molarity = Number of moles of solute / Volume of solution (in liters).

How is the dilution of a solution calculated using molarity?

The dilution of a solution can be calculated using the formula: M₁V₁ = M₂V₂, where M₁ and V₁ are the initial molarity and volume, and M₂ and V₂ are the final molarity and volume after dilution.

What is the difference between molarity and molality?

Molarity refers to the number of moles of solute per liter of solution, while molality refers to the number of moles of solute per kilogram of solvent. Molarity uses volume of solution, and molality uses mass of solvent.