Chapter 15 Flashcards
What do the coefficients in a balanced equation give, where all substances are gases?
Gives us the ratio of the amounts (in mol) of reactants and products.
How can the mole ration be used?
In calculating the masses of reactants and products.
What are the four steps in mass-mass problem?
- Write a balanced equation.
- Calculate the amount (in mol) of the substance with the known mass. N=m/M
- Use the mole ration of the equation to calculate the amount (in mol) of the required substance.
- Calculate the mass required. n=m/M
What step is changed with stoichiometry involving solutions?
Step 2. Uses the formula n= c x v
What is the limiting reagent?
The reactant that is used up in the reaction forcing it to stop.
What is the excess reagent?
The reactant that is said to be in excess when some of it remains when the reaction has finished.
How do u identify the limiting and excess reagents?
Divide the amount of mol by the coefficient in the equation.
What does volumetric analysis determine?
The concentration of acids and bases.
What is a standard solution?
The solution of accurately known concentration.
What does volumetric analysis involve?
Reacting the solution of unkown concentration with a solution of accurately known concentration.
What is a volumetric flask used for?
Used to prepare a standard solution of sodium carbonate. An accurately weighed sample of sodium carbonate is placed in the flask and dissolved in de ionised water to form a specific volume of solutions.
What is a pipette used for?
To measure accurately a specific volume of the solution of hydrochloric acid. The known volume or aliquot is then poured into a conical flask ready for analysis.
What is the equivalence point?
The point in a titration when the reactants have reacted in their correct mole ratios.
What is a titre?
The volume of liquid, measured by a burette, used in a titration.
What equipment is needed in volumetric analysis?
Volumetric flasks, pipettes, burettes
