Question

6.) Suppose that student performed the experiment and calculations perfectly in the atomic spectra experiment except for the following: unknown to the student, the diffraction gratings rating (number of grooves/cm) was less than the label indicated. would the student calculations frequency for the yellow line of the mercury be equal to , higher than or lower than the true value. Explain

7.) when a sample of Ba (CIO3)2 was decomposed, 273 mL of dry O2 were obtained at a temperature of 24°Cities and an atmospheric pressure of 1.189 atm.
Ba (CIO3)2 (s) (aq) 》BaCI2 (aq) + 3 O2 (g)

A) How many Mol of O2 gas were produced? show work

B) How many grams of Ba (CIO3)2 (MM=304.3) were decomposed.

Answer 1

Ba (CIO3)2 (s) (aq) ---> BaCI2 (aq) + 3 O2 (g)

(A)

We know that ideal gas equation is PV = nRT

Where

T = Temperature = 24 oC = 24+273 = 297 K

P = pressure = 1.189 atm

n = No . of moles = ?

R = gas constant = 0.0821 L atm / mol - K

V= Volume of the gas = 273 mL = 0.273 L

Plug the values we get n = (PV)/(RT)

= 0.0133 moles

Therefore the number of moles O2 produced is 0.0133 mol

(B) From the balanced reaction ,

1 mole of Ba (CIO3)2 produces 3 moles of O2

M moles of Ba (CIO3)2 produces 0.0133 moles of O2

M = ( 0.0133x1)/3

= 4.44x10^-3 moles

So mass of Ba (CIO3)2 decomposed , m = number of moles x molar mass

= 4.44x10^-3 moles x 441.5 g/mol

= 1.959 g