How many moles are in 37.9 g of NaHCO3?

Question

(Useful data: Atomic masses: C = 12.01, O = 16.00, H = 1.01, Na = 22.99)

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Answer 1 · 2018-04-15T10:07:21

Number of moles = #"given mass"/"molar mass" #

#=> 37.9/(23+1+12+16(3))#

#=> 38/84#

#=> 0.452 " moles"#

Answer 2 · 2018-04-15T10:10:19

#approx 0.451 mol#

Find molar mass of #NaHCO_3# by adding the molar mass of all the individual atoms:
#M_r=(22.99)+(1.01)+(12.01)+3(16.00)=84.01 gmol^-1#

Use the formula:

#n=(m)/M#

#n#=number of moles
#m#=mass in grams of sample
#M#=molar mass of the compound

Hence:

#n=(37.9)/84.01#

#n approx 0.451 mol#