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Chemistry Stoichiometry - Limiting Reactants

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The fizz produced when an Alka-Seltzer® tablet is dissolved in water is due to the reaction between sodium bicarbonate (NaHCO3) and citric acid (H3C6H5O7): 3NaHCO3(aq)+H3C6H5O7(aq)>>3CO2(g)+3H2O(l)+Na3C6H5O7(aq)
In a certain experiment 1.05g of sodium bicarbonate and 1.05g of citric acid are allowed to react.

- Which is the limiting reactant? Sodium bicarbonate or citric acid?
- How many grams of carbon dioxide form?
- How many of grams of the excess reactant remain after the limiting reactant is completely consumed?

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Solution Preview

- Which is the limiting reactant? Sodium bicarbonate or citric acid?

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

moles of NaHCO_3=1.05 g NaHCO_3×(1 mol NaHCO_3)/(84.006 g NaHCO_3 )
=0.012499 mol NaHCO_3

moles of〖 H〗_3 C_6 H_5 O_7=1.05 g 〖 H〗_3 C_6 H_5 O_7×(1 mol 〖 H〗_3 C_6 H_5 O_7)/(192.12532 g H_3 C_6 H_5 O_7 ...

Solution Summary

The solution shows in steps how to determining the limiting reactant and the amount of grams that are formed from carbon dioxide and excess reactants.

See Also This Related BrainMass Solution

Calculating the Equilibrium Constant: Change in Free Energy

Survey of physical chemistry

State all of the assumptions (e.g. ideal gas etc).

(previous reaction is 2H??2(g) + O2(g) ----> 2H2O(g))

Given the reaction in the previous question at 298 Kelvin where H2 has a partial pressure of 0.10 bar, O2 is at 0.20 bar, and H2o is at 1.5 bar:
(a) Determine the direction and quantify the change in free energy the reaction must undergo to reach equilibrium.

(b) Calculate the equilibrium constant.

(c) Illustrate the reaction on a plot of Free Energy versus % Reactants/Products (show ?GO, the approximate position of Q for the given partial pressures, and the position of Q at equilibrium).

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