Acompound with a molar mass of 102.133 g/mol contains an element with a subscript of 5 . the element is 58.80 g per 100.0 g compound. determine the molar mass (g/mol) of the element.

12.0108408

Explanation:

Denote the element with a letter like say X. Since it has a subscript of 5, then, X5.

Molecular mass=102.133g/mol.

% of X in compound =58.8/100

=0.588

Mass of X in the compound = 0.588*102.133 ( the % of X in compound * molar mass of compound)

= 60.054204

X5=60.054204

Then element X has a mass of 60.054204/5=12.0108408

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

14 days is the half-life of phosphorus-32