# What is the molar mass of NaHCO_3

## How much sodium hydrogen carbonate is there in a vitamin C tablet?

1st calculation step:

Work orders:
1.
Outρ= m / V [g / L] becomes: m =ρ * V;
2. Calculation of the substance portion m (CO2):
m (CO2) = 1.83 g / L * 0.085 L (average value from 10 student experiments)

m (CO2) = 0.1555 g CO2; This mass of CO2 corresponds to the average weight of 10 tablet pieces of the vitamin C tablet: 0.88 g

1. Intermediate result: 0.88 g of vitamin C tablets produce 0.1555 g of CO2 ;

The Molar mass of citric acid: 192 g / mol;
The molar mass of CO2 : 44 g / mol;
The molar mass of NaHCO3: 84 g / mol;

2nd step: Establishing the reaction equation:

C.6H8O7  3 NaHCO3   —> 3  CO2    +   3 H.2O + C6H5O7N / A3(aq)

Molar masses: 192 g / mol + 252 g / mol ----> 132 g / mol + 54 g / mol + 258 g / mol

Control: sum on the left: 444 g / mol Sum on the right: 444 g / mol

After Stoichiometric equation so arise from 1 Mole citric acid and 3 Moles of sodium hydrogen carbonate 3 Mole CO2 = 132 g CO2 .

3rd step: Calculation of the amount of substance n = m / M

The released portion of substance of m (CO2) = 0.1555 g corresponds to n (CO2) = 0.003535 mol = 3.535 mmol
If n (CO2) = 0.003535 mol, then according to the reaction equation n (NaHCO3) = 0.003535 mol.
Conversion of n (NaHCO3) above m = n * M : m (NaHCO3) = 0.29696 g

4th step: Determination of the mass fraction ω (NaHCO3) on the tablet:

The bulk of the Tablet weight was: 0.88 g = 100%. Then 0.2969 g NaHCO correspond3 = 33,74 %≈34 %

Overall result: mass fraction
ω (NaHCO3) = 34 %

Work orders:
1. Calculate the Portion of fabric m and theMass fractionω (citric acid) in the tablet.

The amount of substance released in the reaction n (CO2) was: n (CO2) = 3.535 mmol

According to the reaction equation, there are 3 moles of CO2 one (1) mole of citric acid;
so the amount of substance n (citric acid) = 1/3 mol CO2 = 1.178 mmol

To m = n * M then the substance portion is citric acid: m (citric acid) = 1.178 mmol * 192 g / mol / 1000 = 0.226 g

The mass fraction of citric acid ω (citric acid) is thus: 25.71% with a tablet mass of 0.88 g = 100%.

2. How high is it Mass fraction of the other substances together? See the table of contents above!

Mass fraction ω (NaHCO3):  34 %
Mass fraction ω (citric acid): 25.71%

Mass fraction ω (vitamin C): 4.5% according to packaging information

Then that is Mass fraction of oligofructose (sugar), starch, sweeteners, flavorings and colorings together:

100% - 64,21 =35,79%