Other Chemistry Answers

1. Xiangling, a chef from Liyue weighed ten prawn samples from a batch of prawn delivery for her restaurant. Based on these data determine the different statistical parameter asked

[You may use the stat function or spreadsheet to calculate the values for mean and standard deviation. Just show your solutions for the values of Qexp and Gexp and your conclusion.]

Prawn 1 51.56 g Prawn 6 54.03

Prawn 2 53.01 g Prawn 7 53.90

Prawn 3 57.89 g Prawn 8 53.51

Prawn 4 52.97 g Prawn 9 52.95

Prawn 5 53.56 g Prawn 10 53.24

a. Determine an outlier using Q-test (95.0% confidence)

b. Determine an outlier using Grubb’s Test (95.0% confidence)

1.     Which of the following has the incorrect assignment of oxidation numbers?

a.      Fe₂O₃ (Fe: 2+, O: 2-)

b.     H₂SO₄ (H:1+, S: 6+, O: 2-)

c.      Cr₂O₇^2- (Cr: 6+, O: 2-)

d.     KCl (K: 1+, Cl: 1-)

2.     Which of the following has the incorrect assignment of oxidation numbers?

a.      H₂O₂ (H: 1+, O: 2-)

b.     NO₃^– (N: 5+, O: 2-)

c.      NO₂ (N: 4+, O: 2-)

d.     K₃PO₄: (K: 1+, P: 5+, O: 2-)

3.    Which of the following has the incorrect assignment of oxidation numbers?

a.      SiO₂ (Si: 4+, O: 2-)

b.     KNO­₂ (K: 1+, N: 3+, O: 2-)

c.      HNO₃ (H: 1+, N: 3+, O: 2-)

d.     NH­₄Cl (N: 3-, H: 1+, Cl: 1-)

Based on the reaction, Sn + Cu²⁺ ⇌ Sn²⁺ + Cu⁺ (in acidic medium)

Calculate the following values:

a.      E°cell

b.     ΔG°

c.      K

d.     E (when [Cu²⁺] = 0.0200 M, [Sn²⁺] = 0.0100 M, and [Cu⁺] = 0.0300 M)

BALANCE THE FOLLOWING REDOX REACTION.. Show your full solution/method. Label each step. Briefly explain what you did in each step (few phrases and direct to the point, example: Balanced the oxygen atoms by adding water.).

a. Fe2O3 + CO ⇌ Fe + CO2 (in acidic medium)

b. Mg + NiO2 ⇌ Mg(OH)2 + Ni(OH)2 (in basic medium)

The chloride ion content of a 250.0-mL seawater sample was titrated against 0.1102 M silver nitrate, requiring 13.56 mL to reach end point. What is the molarity of the chloride ion in the seawater sample?

The purity of a sample of sodium oxalate, Na₂C₂O₄, is determined by titrating with a standard solution of KMnO₄. If a 0.5116-g sample requires 35.62 mL of 0.0400 M KMnO₄ to reach the titration’s end point, what is the %w/w Na₂C₂O₄ in the sample.

 A 3.650-g sample containing bromate and bromide was dissolved in sufficient water to give 

290.0 mL. After acidification, silver nitrate was introduced to a 25.00-mL aliquot to precipitate 

AgBr, which was fil- tered, washed, and then redissolved in an ammoniacal solution of potassium 

tetracyanonickelate(II)

Zinc reacts with element X to form a compound used as rat poison. In a chemical analysis, it is found that 3.90g zinc combines with 1.24g X to form the compound with empirical formula Zn3X2. Determine the relative atomic mass of element X.

[Relative atomic mass: Zn, 65]

For the following redox reaction: MnO₄⁻ (aq) + Ni (s) → MnO₂ (s) + Ni²⁺ (aq). Show how you would balance the reaction if it were in an acidic solution. 

Nickel metal, Ni (s), was left in a solution of aluminum (III) ions (Al³⁺), iron (II) ions (Fe2⁺), and copper (II) ions (Cu²⁺). What reaction is most likely to be spontaneous? Write a balanced redox reaction equation for the reaction.