Stoichiometry Flashcards
1 Mole
6.022 x 10^23
3 moles molecules = _____________ molecules
- 06 x 10^23
* Multiply by 6.02 x 10^23 to get # of atoms or molecules
2.5 moles of doughnuts = ___________ doughnuts
15.05 x 10^23
12.04 x 10^23 = __________moles
2 moles
*Divide by 6.02 x 10^23 to find # of moles
Gram Formula Mass
The mass in grams of 1 MOLE of an atom or compound
How to calculate GFM
multiply the amount of an element (subscript) in a compound by its atomic mass and add up with other
ex: H2O
H = 2 x 1.0 O = 1 x 16.0 -----> GFM = 18.0
Mole to Mass conversion
moles = mass
————
GFM
Mole Ratio Calculation
- Balance equation
- Make proportion
3: Givens on numerators and unknowns and needed in denominator
How many moles of O2 are needed to produce 7 moles of CO2?
ex: C2H4 + 3O2 ——> 2CO2 + 2H2O
Proportion:
3 2
– = –
x 7
Percent Composition Equation
Mass Part
—————– x 100
Mass Whole
What is the percent composition formula for the mass of Mg in the compound MgCl2
24
—- x 100 = 26%
94
Hydrates
Any ionic compound that has a specific number of water molecules bonded within its crystal structure
Uses of Hydrates
- Used to absorb water from environment
- Silica packets in shoe boxes
- Ice Melt
- Epsom Salts
- Some sheet rock
- For building homes
Anhydrous Salt
An Ionic compound that attracts water
Empirical Formula
Simplest form of subscripts
ex: C3H4O3
Molecular formula
Unsimplified form of subscripts
ex: C6H12O6
