Which of the following is not an indication of a chemical change

What is important to study for nios grade 12 chemistry? i have only one month left.

Imagine that twenty i. u.’s of enzyme z were catalyzing the above reaction for one minute, under vmaxconditions, in a 3.00 ml assay volume. the assay is buffered with 20 mm phosphate buffer, ph 7.60. what will the ph be at the end of that one minute?

Define the kinetic molecular theory