In nature, oxygen has three common isotopes. The atomic masses and relative abundances of these isotopes are given in the table below. Isotope Atomic Mass (amu) Relative Abundance O-16 15.995 99.759% O-17 16.995 0.037% O-18 17.999 0.204% Calculate the average atomic mass of oxygen. Show all of your calculations below.

The average atomic mass of oxygen is 15.999 amu

Explanation:

Mass of isotope O-16 = 15.995 amu

% abundance of isotope O-16= 99.759 % =

Mass of isotope O-17 = 16.995 amu

% abundance of isotope O-17 = 0.037% =

Mass of isotope O-18 = 17.999 amu

% abundance of isotope O-18 = 0.204% =

Formula used for average atomic mass of an element :

Thus the average atomic mass of oxygen is 15.999 amu

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