1.) Which criteria did you use in this lab activity to determine whether a subst
ID: 937004 • Letter: 1
Question
1.) Which criteria did you use in this lab activity to determine whether a substance was a:
a) strong electrolyte?
b) weak electrolyte?
c) nonelectrolyte?
2.) Why is it necessary to use deionized water when testing the conductivity of aqueous solutions?
3.) Aqueous ammonia, NH3(aq), and acetic acid, HC2H3O2(aq), solutions of equal concentrations, conduct electric current equally well (that is, rather poorly). Explain why the addition of one solution to the other results in a substantial increase in electrical conductivity. Explain AND use chemical equations to make your point .
4.) Ammonium sulfate and barium hydroxide solutions are each very good conductors. However, when equal volumes of solutions of equal concentrations are mixed, a dramatic decrease in conductivity is observed. Explain AND use chemical equations to make your point.
5) Ordinary tap water has relatively low conductivity. Deionized water has even lower conductivity but isn
Explanation / Answer
2)Any measured conductivity should be due to the solute particles and not the solvent particles.
3)NH3(aq) + HC2H3O2(aq) ----> C2H3O2-(aq) + NH4+(aq)
The reaction is a neutralization reaction between a weak base and a weak acid. The product is a salt (NH4C2H3O2) that is a strong electrolyte, therefore an increase in the conductivity of the solution is observed.
4)NH4SO4(aq) + Ba(OH)2(aq) ---->BaSO4(s) + H2O(l) + NH3(g)
In the reaction above there is a neutralization as well as a precipitation reaction. Both of the reactants are strong electrolytes, but the products formed are a solid, a liquid and a weak electrolyte (NH3). So as the reaction proceeds one observes the conductivity decreasing. At the equivalence point the conductivity of the solution is low because the only ions present are NH4+ and OH-.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.