Masess, Moles, and Concentration – Grade 12 Chemistry Module 1

This set of flashcards covers essential concepts from the Grade 12 Chemistry module on Masses, Moles, and Concentration, including definitions and formulas relevant to isotopes, relative atomic masses, Avogadro's number, molar calculations, stoichiometry, and solutions.

What are isotopes?

Isotopes are atoms of the same element with the same number of protons but different number of neutrons.

What is Relative Atomic Mass (Ar)?

Relative Atomic Mass (Ar) is the average mass of one atom of the element compared to 1/12 of the mass of a carbon-12 atom.

What is Avogadro's number?

Avogadro's number, denoted as NA, is 6.02 imes 10^{23} and represents the number of particles in one mole of a substance.

What is the mass of one mole of carbon-12?

The mass of one mole of carbon-12 is 12 grams.

How do you calculate the percentage composition of an element in a compound?

Percentage composition can be calculated using the formula: % by mass = (mass of element in 1 mole of compound / molar mass of compound) x 100%.

What is the relationship between molar mass and relative atomic mass?

The molar mass of an element is numerically equal to its relative atomic mass expressed in grams per mole (g/mol).

What is stoichiometry?

Stoichiometry is the calculation of relative quantities of reactants and products in chemical reactions, based on the Law of Conservation of Mass.

Define theoretical yield.

Theoretical yield is the amount of product expected to form from a chemical reaction based on the stoichiometry of the balanced equation.

What is a limiting reactant?

A limiting reactant is the reactant that is completely consumed in a chemical reaction, limiting the amount of product that can form.

How do you prepare a standard solution?

A standard solution is prepared by dissolving a known mass of solute in a specific volume of solvent.

What is molarity?

Molarity is a measure of concentration expressed as moles of solute per liter of solution (mol/dm³).

What is dilution?

Dilution is the process of reducing the concentration of a solute in a solution, usually by adding more solvent.

What is molecular formula?

The molecular formula is the true formula of a compound, showing all the atoms present in a molecule.

What is the formula to convert mass to moles?\n\n

To convert mass to moles, use the formula: ( \text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} ).\n\n

How do you convert moles to particles?\n\n

To convert moles to particles, multiply the number of moles by Avogadro's number: ( \text{particles} = \text{moles} \times 6.02 \times 10^{23} ).\n\n

What is the molar mass of a substance?\n\n

The molar mass is the mass of one mole of a substance, usually expressed in grams per mole (g/mol).\n\n

How do you calculate the number of particles in a given mass?\n\n

To calculate the number of particles in a given mass, first convert the mass to moles using ( \text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} ), then multiply the moles by Avogadro's number.\n\n

What unit is molar mass expressed in?\n\n

Molar mass is expressed in grams per mole (g/mol).\n\n

If you have 24 grams of carbon-12, how many moles of carbon do you have?\n\n

To find moles: ( \text{moles} = \frac{\text{mass}}{\text{molar mass}} = \frac{24 \, \text{g}}{12 \, \text{g/mol}} = 2 \, \text{moles} ).\n\n

How many particles are there in 3 moles of water (H₂O)?\n\n

To find particles: ( \text{particles} = 3 \, \text{moles} \times 6.02 \times 10^{23} \approx 1.81 \times 10^{24} \, \text{particles} ).\n\n