2.1.2 - Compounds, Formulae & Equations Flashcards
Nitrate
NO3(-)
Carbonate
CO3(2-)
Sulphate
SO4(2-)
Hydroxide
OH(-)
Ammonium
NH4(+)
Zinc
Zn(2+)
Silver
Ag(+)
What is a mole?
A mole is a quantity of substance that contains the same number of entities (atoms, molecules, ions, etc.) as there are in 12 grams of carbon-12. This number is called Avogadro’s constant.
What is Avogadro’s constant?
Avogadro’s constant is the number of particles (atoms, molecules, or ions) in one mole of a substance. Its value is 6.022 × 10²³ particles per mole.
What is the formula for calculating the number of particles in a sample?
The number of particles can be calculated using the formula:
Number of particles = (Number of moles) × (Avogadro’s constant)
What is the molar mass?
The molar mass is the mass of one mole of a substance, usually measured in grams per mole (g/mol). It is numerically equal to the relative atomic or molecular mass of the substance.
What is the relationship between moles, mass, and molar mass?
The number of moles can be calculated using the formula:
Moles = Mass (g) / Molar mass (g/mol)
How do you calculate the number of moles in a sample?
The number of moles is calculated by dividing the mass of the substance by its molar mass:
Moles = Mass (g) / Molar mass (g/mol)
What is the molar volume of a gas at standard temperature and pressure (STP)?
The molar volume of a gas at STP (0°C, 1 atm) is 22.4 dm³/mol. This is the volume occupied by one mole of any ideal gas at STP.
What is the ideal gas equation?
The ideal gas equation is:
PV = nRT
Where:
P = pressure (Pa)
V = volume (m³)
n = number of moles
R = gas constant (8.31 J/mol·K)
T = temperature (K)
What is the relationship between moles and volume for gases at STP?
At STP, the volume of one mole of an ideal gas is 22.4 dm³. The number of moles of gas can be calculated using:
Moles = Volume (dm³) / 22.4 dm³
How do you convert volume from liters to dm³?
1 liter (L) = 1 dm³. So to convert from liters to dm³, simply use the same numerical value.
How do you calculate the moles of gas using volume and pressure?
The number of moles of gas can be calculated using the ideal gas equation:
n = PV / RT
Where P is pressure, V is volume, R is the gas constant, and T is temperature in Kelvin.
What does STP stand for, and why is it important?
STP stands for Standard Temperature and Pressure, which is 0°C (273 K) and 1 atmosphere (1 atm) pressure. It’s important because the volume of gases at STP is constant, allowing for comparisons between gases.
How do you calculate the moles of a substance from its concentration in a solution?
The number of moles can be calculated using the formula:
Moles = Concentration (mol/dm³) × Volume (dm³)
What is the concentration of a solution?
The concentration of a solution is the amount of solute (in moles) dissolved in one liter of solution, typically measured in moles per liter (mol/dm³).
How do you convert volume from cm³ to dm³?
To convert from cm³ to dm³, divide the volume in cm³ by 1000.
1 dm³ = 1000 cm³
What is relative atomic mass?
The relative atomic mass is the weighted average mass of the atoms of an element, taking into account the abundance of its isotopes. It is usually measured relative to the mass of carbon-12.
How do you find the mass of one mole of a compound?
The mass of one mole of a compound is the molar mass, which is the sum of the relative atomic masses of the elements in the compound, measured in g/mol.
What is the relationship between moles and particles?
The number of particles (atoms, molecules, ions) in one mole of a substance is equal to Avogadro’s constant (6.022 × 10²³ particles per mole).
How do you calculate the number of particles in a given number of moles?
The number of particles can be calculated by multiplying the number of moles by Avogadro’s constant:
Number of particles = Number of moles × Avogadro’s constant
What is the empirical formula?
The empirical formula is the simplest whole-number ratio of elements in a compound. It is derived from experimental data, such as the masses of elements involved.
What is the molecular formula?
The molecular formula gives the exact number of atoms of each element in a molecule of a compound, which may be a multiple of the empirical formula.
How do you determine the empirical formula from experimental data?
To determine the empirical formula, convert the masses of elements in the compound to moles, then divide the moles of each element by the smallest number of moles to get the simplest ratio.
What is percentage composition in chemistry?
Percentage composition refers to the percentage by mass of each element in a compound. It can be calculated using the formula:
Percentage composition = (Mass of element / Molar mass of compound) × 100
How do you calculate the moles of solute in a solution from its volume and concentration?
The moles of solute can be calculated using:
Moles = Concentration (mol/dm³) × Volume (dm³)
What is the significance of Avogadro’s constant in chemistry?
Avogadro’s constant allows chemists to relate the macroscopic amount of substance (in grams) to the number of particles (atoms, molecules, ions), making it possible to perform calculations in chemical reactions.
