Experiment 1-Stoichiometry and Volumetric Analysis Experiment 1: Post-Laboratory

Question

Experiment 1-Stoichiometry and Volumetric Analysis Experiment 1: Post-Laboratory Exercise For o to half a bonus mark, write the answers to the following questions on a separate sheet of paper cand submit along with your prelabs for the next prac. Remember include your name and yoxr demonstrator's name on each page. 1. Explain the meaning of the following terms: (a) primary standard, (b) secondary standard and give two properties of ammonium iron(II) sulfate that, together, make it suitable as a primary standard. 2. Explain the difference between an end point and an equivalence point of a titration. 3. Choose the appropriate word within the parentheses to complete the following sentence. In general, a species experiences an increase in its oxidation number when the species is being (oxidised reduced). Conversely, a species experiences a decrease in its oxidation number when the species is being (oxidised reduced). 4. In the net ionic equation written on page 6, determine the oxidation number of oxygen in hydrogen peroxide and in the diatomic oxygen molecule. Is the conversion of H2O(aq) to O2(g) an example of oxidation or an example of reduction? Do we call hydrogen peroxide in this reaction a reducing agent or an oxidising agent? How many electrons are lost or gained by the two oxygen atoms in H202 when this molecule is converted to O2? 5. Which of the following quantities is the same on each side of a net ionic equation (i) (ii) (iii) (iv) The number of cations? The total charge on all the ions? The number of atoms of each element? The total number of ions? 6. Based on your experience in Experiment 1, describe how you would prepare 250.0 mL of 0.0550 mol L NH4Cl(aq). Next, 10.00 mL of this solution was delivered to another 250.0 mL volumetric flask and distilled water was added to the mark. What is the concentration of the second NH4Cl(aq) solution?

Explanation / Answer

Answer:

1)

Primary Standard:

These are solutions made out of primary standard substances which are extremely pure (99.9%)

and are less or nor reactive. It is used to standardize secondary standards and other reagents

some of the examples are pure iron, NaC2O4, As2O3, K2Cr2O7, KBrO3

Secondary standards:

These are the solutions made specifically for a certain analysis (not very pure)

these are comparatively more reactive. these are used to calibrate analytical equipment and analytical techniques

some of the examples are NaOH

Ammonium Iron(II) Sulfate is a primary standard because it is stable and is available in the highly pure form

2)

An equivalence point is when the moles of a standard solution equal the moles of a solution of unknown concentration

The point where there is a color change in the titration is the endpoint

3)

increase in oxidation number: oxidize

a decrease in oxidation number: Reduced

Please rate it if it helped you

Thanks :)

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.