Unit 3 Stoichiometry And The Mole Flashcards
Define precision
How close the data is to each other
Define Accuracy
How close the data is to the true value
What are the three types of errors?
- Random Error
- Gross Error
- Systematic Error
What is Avogadro’s Number?
6.022*10^23
What is the significance of Avogadro’s Number?
6.022*10^23 is one mole
What is the symbol for Avogadro’s Number?
L
What is the formula to find moles? and what dose each variable represent?
n = N / L
n is moles
N is number
L Avogadro’s number
What are the synonyms for Molar Mass?
Atomic Mass
Molecular Mass
Formula Mass
What is the formula for mass - mole conversions? and what do the variables represent?
m = n*MM
m is mass
n is moles
MM is molar mass
What are the four types of formula calculations?
1) Determine the empirical formula form the molecular mass
2) Determine the molecular formula given empirical formula and molar mass
3) Determine the percent composition by mass from a formula
4) Determine the empirical formula from percent composition or experimental data
What are the states of matter and their symbols?
solid (s)
liquid (l)
gaseous (g)
aqueous (aq)
What is the Law of Conservation of Mass?
Matter cannot be created nor destroyed but only changed in form during a chemical reaction
What is the volume of one mole of any gas at STP?
22.7 L or 22.7 dm^3
What does STP mean and what are the conditions?
Standard Temperature and Pressure
0°C
100 kPa
What is the formula to determine percent yield?
percent yield = experimental yield / theoretical yield *100
What is the “four step” method?
1) Balance chemical equation
2) Determine the number of moles for the substance whose quantity is given
3) Identify the substance you are required to find the quantity for and determine the mole ratio from the coefficients (ratio is - “given value : required value”)
4) Convert the moles of the required substance into the units needed
Define hydrated ion
A metal ion that is chemically bonded to a water molecule
Define salt hydrates
salt containing water molecules
Define anhydrous salt
A salt hydrate that releases water when heated
What are the steps for calculating the empirical formula of hydrates?
1) Determine the mass of water driven out
2) Convert mass of water to moles
3) Determine mass of anhydrous salt
4) Convert mass of anhydrous salt to moles
5) Divide moles of water by moles of anhydrous salt to find whole number ratio
Define limiting reactant
The reactant in the reaction that limits the amount of product that forms (will be the reactant that is completely used up)
How do you find the limiting reactant?
Use the four step method to find the yields of both reactants and the smaller reactant yield will be your limiting reactant
