Assume that you used a 0.660 g piece of pure aluminum in the synthesis of alum and obtained a 63.5% yield of alum. How many grams of alum did you obtain?

1.015g

Explanation:

From the question,

Mass of Al used = 0.660g

The percentage yield = 63.5%

Mass of Alum used = y

To find the mass of Alum used, do the following:

%yield = Mass of Al /Mass and Alum

65% = 0.660/y

65/100 = 0.660/y

Cross multiply

65 x y = 0.660x100

Divide both side by 65

y = (0.660x100) / 65

y = 1.015g

The mass of alum obtained is 1.015g

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.