Fakeium has four isotopes found on Earth but they’ve only been recently discovered. Do your part as a scientist and calculate the average atomic mass for fakeium so it can be added to the periodic table. Fa - 85 is 31% of all the isotopes found.

Fa - 86 is 12% of all the isotopes found.

Fa - 87 is 38% of all the isotopes found.

Fa - 88 is 19% of all the isotopes found.

CHOICES:

84.65 g

87.00 g

87.50 g

86.45 g

86.45 g

Explanation:

Given data:

Percent abundance of Fa - 85 = 31%

Percent abundance of Fa - 86 = 12%

Percent abundance of Fa - 87 = 38%

Percent abundance of Fa - 88 = 19%

Average atomic mass of Fa = ?

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)+ (abundance of 3rd isotope × its atomic mass) + (abundance of 4th isotope × its atomic mass)   / 100

Average atomic mass = (31×85)+(12×86) +(38×87)+(19×88) /100

Average atomic mass =  2635 +1032 +3306 +1672 / 100

Average atomic mass  = 8645 / 100

Average atomic mass = 86.45

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

answersilicon (si); oxygen (o);