Stochiometry Quiz 2 Flashcards
Stoichiometry
The mathmatics of the balanced equation
Calculations of quantities of materials consumed and produced in chemical reactions
Conposition Stoichiometry
Mass relationships of elements in compound
Reaction Stoichiometry
Mass relationships between reaactants and products in a chemical reaction
Mole to Mole Calculations
The coefficients in the balanced equation represent the smallest whole nymber mole ratio between reactants and products
Mole Ratio
A balanced equation’s coefficients telling us the ratio between reactants and products
Steps to Mole Ratio
- Start with balanced equation and given value
- Immediatly convert to moles
- Convert from moles of given to moles of unknown
- End with unknown in moles of convert to unit of unknown
Steps to Mass Conversion
- Convert grams to moles using molar mass of known value
- Convert moles of known to moles of unknown using mole ratio
- Convert unknown moles to grams using molar mass of unknown
Gas Conversions
At STP all gases have a volume of 22.4L
The gas ratio is equivalent to the molar ratio
Important
Do not reduce conversions
Never use conversion factors for sig figs
Double molar mass for diatomics but not volume
Every equality makes two conversion factors
Other Conversions to Remember
Avagadros’ number 6.02x20^23 representative particles
Molar mass xg = 1 mol
Molar volume 22.4L = 1 mol
Theoretical Yield
Amount of product that should be produced
Found with mass stochiometry
Theoretical Yield Definition
The maximum amount of product produced froma given amount of reactants based on stochimetric equations
Calculated value
Actual Yiled
Must be product, not reactant
Found by actually doing experiment or given in equation
Actual Yield Definition
The amount of product actually pridcued in the lab
Value is given in a problem or determined in an experiment
Percent Yield
Reaction typically does not yield 100% of theotrtical yield
Found as comparison or percent efficiency
Percent Yield Definition
The actual amount of a product produced compared to the theoretical amount
Value stated as a percebtage
Situations that Affect Actual Yield
Human error
Reaction does not go to completion
Loss of product through spillage, vaporitzation, etc.
Purity of reactants
Percent Yield Formula
% yield = (actual yield/theoretical yield) x 100
Limiting Reactant
Used up in a reaction
Determines amount of product
Excess Reaction
Added to ensure the other reactant is completely used up
Cheaper and easier to reuse
Steps to Limiting Reactant
- Write a balanced equation
- For each reactant, calculate amount of product formed
- Smaller answer indictaes the limiting reactant and maximum amount of product that can be produced
Finding How Much Excess Reaction
Use limiting reactant value that is given as the known value and make the excess reactant value unknown and solve for it
Finding How Much Excess Reaction is Unreacted
Subtract amount of excess reaction that reacted in original problem to emount in excess reaction problem
