Answer:
number of moles in 79.91g of beryllium chloride = 1.000 moles
What is a mole?
The mole (symbol - mol) is a unit of amount of substance in the International System of Units (SI). The mole is defined as containing 6.02214076×10²³ elementary entities. These may be atoms, ions, molecules, etc. The mole is used to simplify quantitative calculations of chemistry.
To calculate number of moles, divide the mass of substance present by the molar mass of substance. The molar mass is the mass in grams of one mole of the substance, and can be calculated by summing the molar masses of the element components of the substance.
Molar mass can be located on a standard IUPAC Periodic Table (International Union of Pure and Applied Science).
Hence, n(BeCl₂) = m÷M = 79.91÷(9.012 + 2×35.45) = 1.000 moles