Identify the number of valence electrons in each atom:
a. Calcium
b. Carbon
c. Sulfur

-Sulfur is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S₈. Elemental sulfur is a bright yellow, crystalline solid at room temperature.

(Atomic number: 16

Electron configuration: [Ne] 3s²3p⁴

Electrons per shell: 2,8,6

Electronegativity: 2.58)

-Calcium is the 20th element, with 20 protons. Since a stable atom has a net charge of 0, we must have 20 electrons.

-Carbon is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust.

(Symbol: C

Atomic mass: 12.0107 u

Atomic number: 6

Electrons per shell: 2, 4

Electron configuration: [He] 2s22p2

Electronegativity: 2.55)

The mass of aluminium hydroxide needed is 150.774 grams.

Explanation:

The chemical equation for the decomposition of aluminium hydroxide follows:

At STP:

22.4 L of volume is occupied by 1 mole of a gas.

So, 65 L of volume will be occupied by =

By Stoichiometry of the reaction:

3 moles of water is produced by 2 moles of aluminium hydroxide

So, 2.9 moles of water is produced by =

To calculate the mass of aluminium hydroxide, we use the equation:

Number of moles of aluminium hydroxide = 1.933 moles

Molar mass of aluminium hydroxide = 78 g/mol

Putting values in above equation, we get:

Hence, the mass of aluminium hydroxide needed is 150.774 grams.