Mole, Molar Mass, Particle, Atom:
1. Mole:
- The mole is a unit of measurement that represents the amount of a substance.
- It is defined as the amount of substance that contains the same number of particles as there are atoms in exactly 12 grams of carbon-12.
- The symbol for the mole is "mol".
2. Molar Mass:
- Molar mass is the mass of one mole of a substance and is expressed in grams per mole (g/mol).
- It is numerically equal to the atomic or molecular weight of the substance.
- The molar mass of an element can be found on the periodic table.
3. Particle:
- A particle refers to an individual entity, such as an atom, ion, or molecule, within a substance.
- The number of particles in a substance can be determined using Avogadro's number, which is approximately 6.022 x 10^23 particles/mol.
4. Atom:
- An atom is the basic unit of matter that cannot be further divided or broken down chemically.
- Atoms are composed of subatomic particles such as protons, neutrons, and electrons.
Equations and Exercises:
1. Equation:
- The number of moles can be calculated using the equation: Moles = Mass / Molar Mass
Example: Calculate the number of moles in 36 grams of water (H2O).
Solution:
Molar mass of water (H2O) = 2(1.01 g/mol for hydrogen) + 16.00 g/mol for oxygen = 18.02 g/mol
Moles = 36 g / 18.02 g/mol = 1.997 mol (approximately 2 moles)
2. Equation:
- The number of particles can be calculated using the equation: Particles = Moles x Avogadro's number
Example: Determine the number of water molecules in 2 moles of water (H2O).
Solution:
Particles = 2 mol x (6.022 x 10^23 particles/mol) = 1.2044 x 10^24 particles
3. Equation:
- The molar mass can be calculated using the equation: Molar Mass = Mass / Moles
Example: Find the molar mass of 0.5 moles of carbon dioxide (CO2).
Solution:
Mass of carbon dioxide (CO2) = Moles x Molar mass = 0.5 mol x (12.01 g/mol + 2(16.00 g/mol)) = 22.01 g
Grade 12 Practical Lesson on Moles:
Topic: Determining Molar Mass Using Colligative Properties
Materials:
- Bunsen burner
- Beaker
- Tripod stand
- Wire gauze
- Thermometer
- Balance
- Unknown solute
- Solvent (water or another suitable liquid)
- Glass stirring rod
- Graduated cylinder
Procedure:
1. Weigh an empty beaker using the balance and record its mass.
2. Add a known amount of the unknown solute (between 0.5 g and 1.5 g) to the beaker and record the total mass.
3. Add a known volume of solvent (e.g., 100 mL) to the beaker and record the total mass again.
4. Heat the beaker on a Bunsen burner until the solute dissolves completely.
5. Allow the solution to cool and record the temperature using a thermometer.
6. Calculate the change in boiling point (∆Tb) using a colligative properties equation (e.g., ∆Tb = Kb x m x i, where Kb is the molal boiling point elevation constant, m is the molality of the solution, and i is the number of dissolved particles).
7. Determine the molality (moles of solute per kilogram of solvent) by using the equation: molality = moles of solute / kilograms of solvent.
8. Calculate the molar mass of the unknown solute using the equation: molar mass = mass of solute / moles of solute.
Note: It is important to follow safety precautions while performing this experiment, including wearing appropriate protective equipment and working in a well-ventilated area.
Overall, this lesson provides an overview of mole properties, including molar mass, particles, atoms, and equations related to these concepts. The practical lesson focuses on a specific application of mole concept, which is determining molar mass using colligative properties. Teachers can further elaborate on the importance of these concepts in various chemical calculations and problem-solving in chemistry.
Lesson Topic mole properties
Write all the facts about mole, molar mass, particle and atom with equation and exercises including solutions to reach question for Grade 12 chemistry .
The same topic moles give the brief and very simple grade 12 practical lesson including all necessary steps
2 answers
The bed definition of science
1 answer