Ch. 4, 13; 24.1 / 16.11  aqueous reactions                   test                 90 points                                  AP chemistry

 

In problems involving any calculation, show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) have the proper number of significant figures in your answer.

1. Using

NaOH             AgNO3
Na3PO4          Pb(NO3)2
Na2CO3         Co(NO3)2
NaI                  Cu(NO3)2                     Mg(NO3)2
Na2SO4          Ba(NO3)2                     Fe(NO3)3

design an experimental protocol to identify and differentiate between

            CuCl2, Cu(NO3)2; Na2SO4, NaOH; Ba(NO3)2

include any observations and its interpretation.  [20 points]


2. A 3.0 g mixture of sodium carbonate and sodium bicarbonate was heated, which reduced the mixture’s mass to 2.0 g.  What is the % of sodium bicarbonate in the mixture prior to heating the sample ?  [15 points]

assume:  2 NaHCO3   →   Na2O(s) + 2 CO2(g) + H2O(g) while the other component in the mixture is unaffected by the heat.

3. In regards to a laboratory activity to determine the unknown concentration of nitric acid, which is put into a beaker and sodium hydroxide in a burette, list the experimental data (not calculations).  [10 points]

4. Lab error analysis.

a. In the sodium carbonate / sodium bicarbonate mixture lab, you assumed (i) only one component in the mixture was sensitive to heat, (ii) there were only these two components in the mixture, and (iii) none of the chemicals in the mixture nor any products due to the heat treatment is hygroscopic.  What’s the effect on the determination of the % of each component in the mixture compared to the case, where the preceding assumptions are valid; if __; justify / rationalize your response.  [15 points]

i. both components are sensitive to heat

ii. there’s contamination by KCl, which is unaffected by heat.

iii. the product in heating the mixture is hygroscopic.

5. How to prepare 100. mL of a 0.75 M sodium hydroxide solution using ___  ?  [20 points]

a. Solid sodium hydroxide

b. 1.25 M sodium hydroxide solution

6.  Plasma contains numerous hormones; e.g. aldosterone, a steroid hormone, and vasopressin, a peptide hormone.  Using a separatory funnel, cyclohexane was added to plasma.  Would the preceding hormones be separated ?  Justify / rationalize your answer.  If these hormones can be separated, then identify the location of each hormone (i.e. plasma versus cyclohexane fraction); justify / rationalize your response.  [10 points]