An alkaline-seltzer tablet contains exactly 100 mg of citric acid, h3c6h5o7, plus some sodium bicarbonate. what mass of sodium bicarbonate is required to consume 100. mg of citric acid by the following reaction? . h3c6h5o7(aq) + 3 nahco3(aq)= 3 h2o(l) + 3 co2(g) + na3c6h5o7(aq).

mass of NaHCO₃  = 0.126 g

Explanation:

balanced chemical equation  

H₃C₆H₅O₇(aq) + 3 NaHCO₃(aq) → 3 H₂O(l) + 3 CO₂(g) + Na₃C₆H₅O₇(aq).

given data

moles of citric acid   = 1 mol  

mas of citric acid = 100 mg

mas of citric acid = 0.1 g

moles of sodium bicarbonate = 3 mol

mass of sodium bicarbonate = ?

Solution

1st we will find out the mole ratio of H₃C₆H₅O₇ and NaHCO₃ from balanced chemical equation

H₃C₆H₅O₇ : NaHCO₃

               1 : 3

Now we find out number of moles of citric acid  

                  moles = mass / molar mass

   moles = 0.1 g / 192.124 g/mol

   moles = 0.0005 mol

now we find out moles (x) of sodium bicarbonate needed for 0.0005 mol of citric acid    

from the balanced chemical equation the mole ratios are:

                  1 : 3

0.0005 mol  :  x

Cross multiply these ratios

    3 × 0.0005 = 1x

          0.0015  = 1 x

          x = 0.0015 mol

Now we will find out the mass of sodium bicarbonate

                  mass   = moles × molar mass

      mass of NaHCO₃  = 0.0015 mol × 84.007 g/mol

      mass of NaHCO₃  = 0.126 g

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.