6 Physical Chemistry 6.5 Chemical Kinetics
P3050301
Kinetics of the inversion of saccharose
Floating point representation of saccharose inversion as a function of time.
Principle
Half-shade polarimeter, 230 V AC
The inversion reaction of saccharose, which is catalysed by protons, produces invert sugar, which is a mixture of glucose and fructose. The reaction is accompanied by a change in the optical rotation of the system. Glucose rotates the polarisation plane of linearly polarised light to the right, while inverted sugar rotates it to the left. A half-shade polarimeter is used for the measurement of the change in the angle of rotation of polarised light during the inversion reaction of saccharose over time. Tasks 1. Determine the specific rotation of saccharose and lactose by measuring the rotation angle of solutions of various concentrations. 2. Determine the rate constant of the inversion of saccharose. What you can learn about ▪ ▪ ▪ ▪
Reaction rate First order reaction Polarimetry Optical rotation
Function and Application Half-shade polarimeter for concentration measurement of optical active solutions. Equipment and technical data
Main articles Half-shade polarimeter, 230 V AC Immersion thermostat Alpha A, 230 V Magnetic stirrer MR Hei-Standard Bath for thermostat, makrolon External circulation set f. thermostat Alpha A Retort stand, 210 × 130 mm, h = 500 mm Set of Precision Balance Sartorius CPA 623S and measure software, 230 V
1 1 1 1 1 1
▪ ▪ ▪ ▪ ▪ ▪ ▪
49224-88
1
35906-93
excellence in science 96
Polarimeter support with built-inlight source and filters Polarimeter tube length 100 and 200 mm 2 scales 0-180 degrees Division 1 degree Vernier reading 0.05 degrees with nonius Light source sodium lamp 589 nm Power supply 230 V / 50 Hz
35906-93 08493-93 35750-93 08487-02 08493-02 37692-00