How many formula units are in a 7.3 x 10-3 gram sample of lithium chloride, LiCI?

formula units

Explanation:

so lets start off by looking at what we have. we have g of LiCl

which is called Lithium Chloride. in order to convert g to moles, we divide the g by the molar mass of Lithium Chloride.

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okay so lets look at the periodic table and we notice that the atomic mass of Lithium is 6.941 and the atomic mass of Chlorine is 35.453. notice that in LiCl there is only one of each. so lets add 6.941 + 35.453 = 42.394 g/mol.

now look at what we were given: converting the given quantity to standard format instead of scientific format, we have 0.0073 grams of lithium chloride. we can convert this to moles by dividing it by its molar mass which is 42.394.

now lets use AVOCADOS NUMBER i mean AVOGADROS NUMBER!! which is

multiply and we get formula units.

if you want to be specific about the significant figures, notice that the given quantity in the question only has two significant figures. so we can alter our final answer to only have two sig figs. lets change it: formula units

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year