C2 Flashcards
What is the relative atomic mass of an atom?
The mean mass of an atom of an element compared to 1/12 the mass of a Carbon -12 atom
What does the chemical formula tell you?
How many atoms of each element there are in a unit of substance
What is the relative formula mass?
The mean mass of a unit of substance compared to 1/12 the mass of a Carbon-12 arom
What is the empirical formula?
The simplest whole number ratio of each of the atoms of each element in a compound
What is a “pure” substance?
A substances that consists of just one element or compound
How can the melting point be used to determine purity of a substance?
The greater the difference between the measured melting point and it’s accepted melting point, the lower the purity is likely to be
How do you determine the melting point?
Heat the substance slowly
Stir the substance as it melts
What is a solute?
The substance that dissolves
What is the solvent?
The substance that the solute dissolves in (a liquid)
What is a solution?
When one substance dissolves in another
What happens when a substance dissolves?
Its particles Speer are and become completely mixed with the particles of the solvent
What does soluble mean?
If a substance is soluble, it means that the substance can dissolve in a solvent
What does insoluble mean?
The substance cannot dissolve in a solvent
What is residue (during filtration)?
The particles that stay behind in the filter paper
What is the filtrate?
The particles of a dissolved solute that are small enough to pass through the filter paper
How does crystallisation work?
When the solvent evaporates slowly leaving the solute behind -heat too strong and you get powder
What is the apparatus needed for crystallisation?
Bunsen burner
Beaker
Tripod
Gauze
Evaporating basin
What are the apparatus needed for filtration?
Filter paper
Funnel
Conical flask
What does simple distillation involve?
Separating a solvent from a solution
What does simple distillation rely on?
The solvent having a much lower boiling point that the solute
What happens during simple distillation?
Solution is heated
Solvent boils, solute does not
Solvent escapes from solution in gas state
Cooled and condensed back into a liquid by a condenser
Collected in a test tube