DATA AND ANALYSIS
Making up the 0.20 M (NH4)2S2O8 solution
Show the calculations for the moles and mass of (NH4)2S2O8 that is required for 60 mL of a 0.20 M (NH4)2S2O8 solution.
(NH4)2S2O8 = 228.18 g/mol
1 mole of a substance in 100 ml solvent = 1 M solution
0.2 mole of a = 0.2 M solution
The weight of the 0.2 mole of (NH4)2S2O8 = (228.18 x 0.2) = 45.636 g
0.2 (M) 100 mL (NH4)2S2O8 solution contains 65.636 g solute
0.2 (M) 60 mL (65.636 x (60) / (1000)) = 2.738 g
To make a 60 mL 0.20 M (NH4)2S2O8 solution one needs 2.738 g of (NH4)2S2O8 solute
Clock reaction data and calculations
The data that you put into Table 3 will be used to compute the rates of each of the three clock reactions.
The moles of I2 produced are (1) / (2) the number of moles of thiosulfate added (see discussion on page 2:4). The total volume in the flask is given in Table 2, but you must convert this into units of liters. With this data, solve for molarity of I2 and for the rate of I2 formation. Notes: the values in each of the three middle columns are the same. Consider using the same exponent for the rates to make comparing them easier.
Table 3
I2 Produced Time (s) (mole)
Total Volume (L)
Molarity of I2 [l]
Rate
2:9
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