A group of students made 5 standard solutions and measured their corresponding a

Question

A group of students made 5 standard solutions and measured their corresponding absorbance values at a wavelenght of 525.0 nm to generate a graph with the following equation: Y= 75.9x + 0.0045.

The colorless reactants Y and Z form unknown X from the reaction: 2Y + Z --->/<---- X

A solution is prepared by mixing the following: 6.00 mL of 0.0150 M Y and 4.00 mL of 0.0150 M Z (mL)

This solution reaches equilibrium, and then is placed in a 1.00 cm wide cuvet and inserted into the spectrometer, producing and absorbance reading of 0.275 at a wavelength of 525.0 nm. Calculate K for the above reaction, including units.

Explanation / Answer

2Y + Z ----------> X

<----------

K = [X]/[Y]^2[Z]

Cocentration of X can be determined the equation

Y = 75.9X + 0.0045

0.275= 75.9X + 0.0045

X = 0.0036M

Initial concentration of Y = 0.0090

Initial concentration of Z = 0.0060

Initial concentration of X = 0

Concentration after equillibrium , Y = 0.0090 -X

Concentration after equillibrium, Z = 0.0060 - X

Concentration after equillibrium , X = 0.0036M

Therefore,

Concentration of Y at eqillibrium = 0.0090 - 0.0036= 0.0054M

Concentration of Y at equillibrium = 0.0060 - 0.0018 =0.0024M

Therefore , K = 0.0036/((0.0054)^2×0.0024)=5.1×10^4

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.