Round off the measurement 0.002 015 5 m to three significant figures.

0.002

Explanation:

The significant figures of a number are digits that are meaningful in trying to resolve a given value. These are actually digits that carry meaning in a given number.

Let s look at  0.002, the zero before the decimal  point carries no real meaning in the number. However, the zeros that precede 2 are all meaningful because the occupy the tenth and hundreth place values.

Hence, there are three significant figure in  0.002.

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