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Flashcards in things to remember Deck (11):
1

x

mass of compound/ mass of empirical formula

2

moles

n = m (mass)/M (Molar Mass)

3

moles (from atoms)

n = N (particles)/ Na (Avogadro)`

4

To find mass of excess reactant unreacted

calculate moles reacted then subtract total amount by the amount reacted. times this by M

5

molecular vs. empirical

molecular: how many atoms of each element in a compound
empirical: the simplest and most reduced RATIO of atoms in a compound

6

steps for hydrate given a percentage of one Element

1) do the ratio (percent given/mass of element times ()percent x/ ()mass of element.). repeat for number of elements in compound
2) add up percentages, 100-x = percent hydrate
3) assume 100g, find moles, divide by smallest= EF

7

percentage yield (What is it, find moles unreacted)

is also a ratio
write down everything. to find amount unreacted, find reacted amount (()mol times mol/()mol of other reactant ) then subtract total amount - reacted to get mol unreacted. times by M to get moles excess unreacted

8

why do you divide by lowest number of moles in EF?

divide because you want to find out how many particles are bonded to each particle of the lowest # of moles

9

what does chemical formula give you

relative amounts of particles/moles. balanced eqn is needed because it shows the amount of moles in relation to different products

10

how to go from atoms to mass and back

Order: # of atoms- # of molecular - Moles - mass
EQN: (chemical formula, avogadro, Molar mass)

11

!!! Molar mass of a compound

is not the molar mass of the EF! It is molar mass of the MF!