Chemistry Answers

What is the PH of a solution having the following H+ concentration?

a. 5*10^-3 M

b. 0.003M

c. 2.0*10^-6

Identify the Lewis acid in the following reaction.

a) ALCL₃ + CL^- ⤑ ALCL₄^-

b) BF₃ + NH₃ ⤑ BF₃ - NH₃

c) SiCL₄ + 2CL^- ⤑ SiCL₆^-2

d) PF₅ + F^- ⤑PF₆

In each of the reactions listed below, identify the Bronsted-lowery acids?

a. CH₃COOH (aq) + H₂O (l) CH₃COO^-(aq) + H₃0⁺ (aq)

b. HCN (aq) + SO4^-2 ↔ CN^-(aq) + HSO₄^-(aq)

c. HF (aq) + NH₃(g) ↔ F^-(aq) + NH₄⁺(aq)

d. HCIO₄(aq) + N₂H₄(aq) ↔ CIO₄^-(aq) + N₂H₅⁺(aq)

an unknown salt when heated with buses flame produced a bright-yellow flame.an aqueous solution of this salt when reacted with dilute HCl related a gas turns lime water milky. upon addition of calcium chloride solution to an aqueous solution of salt ,a white precipitate is formed. what is the unknown salt?

18. In a redox titration, potassium permanganate, KMnO4, was standardized using a 19.60 g/L

FeSO4(NH4)SO4.6H2O, (molar mass = 392.21 g/mol) standard solution. A 20.00 mL of the

standard solution, acidified with H2SO4 was put in a conical flask. A titre volume 15.50

mL of KMnO4 solution was required to reach the end-point. The titration reaction is:

Fe2+(aq) + MnO4

−(aq) → Fe3+(aq) + Mn2+(aq)

(i) Balance the above redox reaction in basic medium.

(ii) Calculate the molarity of the standard solution.

(iii) Determine molarity of MnO4-(aq) in the burette.

1.      Human colour vision is “produced” by the nervous system based on how three different cone receptors interact with photons of light in the eye. These three different types of cones interact with photons of different frequency light, as indicated in the following chart:

Cone Type   Range of Light Frequency Detected

S                          6.00-7.49 x 10¹⁴ s^-1

M                         4.76-6.62 x 10¹⁴ s^-1

L                          4.28-6.00 x 10¹⁴ s^-1

           What wavelength ranges (and corresponding colours) do the three types of cones

detect?

1.      Subshells half-filled with electrons are particularly stable. Can you suggest a possible

physical basis for this claim?

If an average fluorine atom has a mass of 3.16×10-23 g, what is the average mass of a chlorine atom in grams?

Calculate the  ΔG° using Hess Law for the reaction: Cu2S(S) + O2(g) ( Cu(s) SO2(g)

2 Cu(s) + S(s)  ( Cu2S(L) Δ    Go  = -86.2 kJ

S(s)  +  O2(g)  (  SO2(g) Δ        Go = -300.1 kJ

NiCl3 is a strong electrolyte.

Determine the concentration of each of the individual ions in a 0.550 M NiCl3

0.550 M NiCl3 solution.