I feel dumb.. how do I find moles? and a few other things.. !!?
also need moles of CO2
Answer:
moles = mass / molecular weight
mass = moles x molecular weight.
molecular weight = 23+ 1 + 12 + 3 x 16 = 84 grams / mole
from atomic mass found here...
http://www.chemicalelements.com/...
so if you have 42 grams of NaHCO3 (which is sodium bicarbonate by the way) you would have .
moles = 42 g / (84 g/mole) = 0.50 moles
if you have 1 mole, then you have this many grams
1 mole x 84 g / mole = 84 grams
for the "also need moles of CO2" , I assume you mean if you have
NaHCO3 <----> NaOH + CO2
you'll notice there is 1 CO2 per 1 NaHCO3 so that
0.5 moles NaHCO3 x (1 mole CO2 / 1 mole NaHCO3) =
0.5 moles CO2
Just look at a periodic table for the atomic masses of each element and add them together.
ex:
CO2
C = 12.01 x 1 =12.01
0 = 16.00 x 2 = 32.00
total = 44.01g/mol
Same thing for the other compound, just add up the individual weights.
If you already have the weight of a compound in grams, and you want to find the number of moles, just find the molar mass of the compound as I showed above, and divide the weight of the compoound you have by the molar mass.
A mole is 6.02 x10^23 particles.
If you take the atomic mass from the periodic table and express it in grams, that is the mass of a mole of something.
Take the mass of each element and add.
NaHCO3 has a total mass of 23+ 1 + 12 + 3(16) =84
CO2 has a total mass of 12 + 2(16) = 44
If we are talking about 1 molecule of the substance, it is expressed in atomic mass units. If we are talking about a mole of it , it is expressed in grams.
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