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the density of ethanol (C2H5OH) is 0.789 g/ml at room temperature. how many H atoms are present in 10.56 cubic meter of ethanol at this temperature?

Oct 21st, 2013
Solution:

Density of ethyl alcohol = mass / volume
Hence,
mass = density * volume
mass = 0.789 g/mL * 200 mL
mass = 157.8 g

Note: volume of solution in above case = 100mL + 100 mL = 200 mL

We know,
Number of moles of ethyl alcohol ( n ) = mass / molecular mass
n = 157.8 / 46
n = 3.43 mol

Note: molecular mass of C2H5OH = 2*12 + 5*1 + 16*1 + 1 = 46 g

Molarity of ethyl alcohol ( M ) = number of moles of ethyl alcohol / total volume (in Litres)
M = 3.43/ 0.2
M = 17.15 g/L

Note: In molarity volume should always be in Litres. Hence, above, Volume = (100 + 100) mL = 200 mL = (200/1000) L = 0.2 L.
Oct 21st, 2013

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Oct 21st, 2013
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Oct 21st, 2013
Dec 7th, 2016
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