Calibration of a measuring instrument is the process of breaking in the instrument when it is new. the process of putting oil in all the moving parts of the instrument. comparing and adjusting the instrument’s measurement to get the data that you expect during your experiment. comparing and adjusting the instrument’s measurement to match a known quantity or another correctly functioning instrument’s measurement.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

level 4 to level 2 : ))

answer; 4 electrons;