13.How many grams of phosphorus (P4) are needed to completely consume 79.2 L of chlorine gas according to the following reaction at 25 °C and 1 atm? phosphorus (P4) ( s ) + chlorine ( g ) > phosphorus trichloride ( l )

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 choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."

plasma is the state of matter where the substance is ionized and has no definite shape or volume. the fact of being ionized makes the substance a good electrical conductor.