Question

please fill in table and then answer questions.

bie(Report) sample identification:Lonmrcia molar concentration of thiosulfate titrant (M): Old Dutch Brend 0.126 Titration1 Titration2 Titration 3 1414.92 5.23 14521 mass of flask (g) mass of lask + bleach ()146.01146 4 14o13 1.01 net mas of bleach (Loqu initial burette reading (mL) .23 053016 final burette reading (mL) 2.20. 341. volume dispensed (mL) moles of thiosulphate titrated (mols) moles of hypochlorite (mols) mass of sodium hypochlorite wt-% of sodium hypochlorite STATISTICS (consult lab manual for proper significant figure determination) Mean % of sodium hypochlorite Standard Deviation Relative Standard Deviation (ppb) Manufacturer's specification to wgst Nad 0 시39 0.15 o .10 CHEM 1017&CHEM 1987 Exp. 8 Questions 1. For equations 2, 3 and 4 in the introduction of the lab manual, indicate the following Equation 2 Equation 3 Equation 4 Species oxidized Species reduced Oxidizing agent Reducing agent 2. What is the oxidation state of every atom indicated below? You may need to consult your textbook or class notes (or online) on how to determine oxidation states H in H:0 (1) O in H:O (1): Cl in Cl (aq): O in OCT (aq): Cl in OCI (aq): Cl in Cl2 (g) O in OH (aq) H in OH (aq): 3 A new bottle of bleach is 5 % by weight sodium hypochlorite. What is the pH of a 5 % by weight solution of sodium hypochlorite? Ka for HOCI -3.5 x 10*. The density of bleach is 1.07 g/mL. Please show all of your work molarity, mol L and consider the Kb of OCT no points without it! Hint: Convert % by weight to -

Answer 1

Given, molar concentration of thiosulfate= 0.126M

It means 1 litre of solution contain= 0.126 moles of thiosulfate

7.6 mL of solution will contain=0.126×7.6/1000=0.95×10^(-3) moles

8.1 mL of solution will contain=0.126×8.1/1000=1.02×10^(-3)

7.2mL of solution will contain=0.116×7.2/1000=0.91×10^(-3)

Molecular mass of bleach=74.44g/mol

1.094 g of bleach(sodium hypochlorite)

Moles of hypochlorite= 1.094/74.44=0.014 moles

1.23 g of bleach

Moles of hypochlorite=1.23/74.44=0.016moles

1.01g of bleach

Moles of hypochlorite=1.01/74.44=0.013 moles

Mass of sodium hypochlorite= 1.094

1.23

1.01

Weight % of sodium hypochlorite=1.094×100/74.44=1.4%

Weight% of sodium hypochlorite=1.23×100/74.44=1.6%

Weight % of sodium hypochlorite=1.01×100/74.44=1.3%

Mean wt% of sodium hypochlorite=1.4+1.6+1.3/3=1.43%

Standard deviation

Mean=1.43%

Subtract mean from each value and then square the values

• (1.4-1.43)^2=(-0.03)^2=0.0009
• (1.6-1.43)^2=(0.17)^2=0.0289
• (1.3-1.43)^2=(0.13)^2=0.0169

Mean of squared numbers:

0.0009+0.0289+0.0169/3=0.0467/3=0.0155

Square root of this number will give standard deviation:

Standard deviation=√0.0155=0.1244

Relative standard deviation= standard deviation×100/mean

=0.1244×100/1.43=8.69