Answer:
73.2g
Explanation:
The reaction expression is given as:
P₄ + 6Cl₂ → 4PCl₃
Given parameters:
Volume of chlorine gas = 79.2L
Unknown:
Mass of Phosphorus needed = ?
Solution:
To solve this problem, let us find the number of moles of the chlorine gas.
Since the condition of the reaction is at STP;
22.4L of gas is contained in 1 mole
79.2L of chlorine gas will contain
= 3.54mole
From the reaction expression;
6 moles of chlorine gas will react with 1 mole of P₄
3.54 mole of chlorine gas will completely react with
= 0.59mole of P₄
Mass of P₄ = number of moles x molar mass
Molar mass of P₄ = 4 x 31 = 124g/mol
Mass of P₄ = 0.59 x 124 = 73.2g
The answer is 3). This is because elements are the simplest form of a substance, and cannot be broken down any further. Compounds on the other hand are much more complex than elements and can be broken down INTO elements.
For example, Na, sodium, is an element and cannot be broken down further. H2O, water, is a compound and can be broken down into Hydrogen and Oxygen.