Unit 1 Flashcards
Moles
What is a mole?
A way to measure things in a relative scale. One mole mole of a substance contains the same number of particles as there are atoms in 12g of carbon12
How many atoms are in 1 mole and what is this called?
6.022 X 10²³ . its called avogradros number
What can you use avogradros number for?
You can calculate the number of atoms of any element.
avo X Moles
if two elements have the same number of moles will they have the same mass?
No they can have different masses
what is molar mass?
It is the mass of one mole of a substance (gmol¹)
Calculate number of moles?
Mass/ Molar Mass
Calculate molar mass?
Mass/ #moles
Calculate Mass?
moles X molar mass
Moles triangle for calculations?
Mass #M X MM
Steps to balancing an equation?
1) Metals (left side periodic table)
2) Non-metals- except H&O
3) H&O
What is empirical formula?
it shows the simplest ratio of atoms
What is molecular formula?
Shows the actual number of atoms
How do you work out empirical formula?
1) mass/mm = #m
2) Divide all values by smallest value
this is ratio
How do you work out molecular formula using empirical formula?
1) mass/mm= #m
2) divide all values by smallest value
3) Multiply the mm of each compound by its ratio and then add them together. If this is the same as the given mass then molecular and empirical are the same. If not
4) molecular formula mm/ empirical formula mm
5) times ratio numbers by this to scale up
What is percentage composition?
It is the percentage mass of each element in a compound
How do you work out percentage composition?
(n X mm of element/ mm of whole compound) X 100
How much space at room temperature does 1 mol of gas take up?
24 dm³
How much space at stp (20C and 1atm) does 1 mol of gas take up?
22.4 dm³
What is the ideal gas law?
pv= nRt
What is the value for the gas constant?
8.314 j mol⁻¹ K⁻¹
What is a volatile liquid?
A liquid that will vaporize easily
Oxidation state of oxygen?
-2
Oxidation state of fluorine?
-1
Oxidation state of chlorine?
-1
Oxidation state of group 1?
+1
Oxidation state of group 2?
+2
Oxidation state of hydrogen?
+1
Balance REDOX reactions
1) Split into half equations
2) Balance
3) Add h20 to balance o and h to balance H
4) add e to balance charges
5) make number of e’s in each half equal so can cancel
6) recombine an cancel all same
