Some Basic Concepts Of Chemistry Flashcards
(19 cards)
What is Absolute density?
Density of the substance
Absolute density is the mass per unit volume of a substance.
Define Relative density or specific gravity.
Density of substance / Density of water at 4°C
Density of water at 4°C is 1 g/mL.
What is Vapour density?
Density of gas / Density of hydrogen at the same temperature and pressure
Vapour density is used to compare the density of gases.
How is the number of moles (n) calculated?
n = Given mass (g) / Molar mass (g/mol)
The number of moles is a measure of the quantity of substance.
What is Mole Fraction?
Moles of component / Total number of moles present in solution
Mole fraction is a dimensionless quantity representing the ratio of moles.
What does ppm stand for in chemistry?
Parts per million
ppm is used to express very dilute concentrations of substances.
What is Degree of hardness of water?
Concentration of calcium and magnesium ions in water
Hardness of water is typically measured in ppm or mg/L.
What is Mass Percentage?
Mass of solute / Mass of solution x 100
Mass percentage indicates the concentration of a component in a mixture.
Define Mass by volume Percentage.
Mass of solute / Volume of solution x 100
This is commonly used in solutions where solute mass is expressed in grams and volume in mL.
What is Volume by volume percentage?
Volume of solute / Volume of solution x 100
This measure is often used for liquid-liquid solutions.
What is Molarity (M)?
Moles of solute / Volume of solution (L)
Molarity is a common unit of concentration in chemistry.
Define Molality (m).
Moles of solute / Mass of solvent (kg)
Molality is used to describe the concentration of a solution based on the mass of the solvent.
What does Percent yield represent?
Actual yield / Theoretical maximum yield x 100
Percent yield is an important measure of the efficiency of a chemical reaction.
Fill in the blank: Molarity (M) = _______.
Moles of solute / Volume of solution (L)
Molarity is a vital concept in stoichiometry.
What is the formula for calculating %w/w?
%w/w = (Mass of solute / Mass of solution) x 100
This formula is used to express the concentration of a solute in a solid mixture.
What is the formula for calculating %w/v?
%w/v = (Mass of solute / Volume of solution) x 100
This measure is useful for solutions where the solute is a solid and the solvent is liquid.
What is the significance of 22.4 L/mol?
Volume of gas at STP
STP refers to standard temperature and pressure.
How do you calculate the volume of gas at STP?
Volume of gas (L) / 22.4 L/mol
This calculation is essential for gas law problems.
True or False: The mass of water at 4°C is 1 g/mL.
True
This value is used for various density calculations.
