Consider the reaction below :
P4(s) + 5O2(g) ---> P4O10(s)
How many grams of phosphorus react with 4.745 x 10^1 L of oxygen at STP to form tetraphosphorus decaoxide?
Here is a site that gives a worked example.
http://www.jiskha.com/science/chemistry/stoichiometry.html
To determine how many grams of phosphorus react with a given volume of oxygen at STP, we need to follow these steps:
Step 1: Convert the given volume of oxygen to the number of moles.
At STP (Standard Temperature and Pressure), 1 mole of ideal gas occupies 22.4 liters. Therefore, we can use this ratio to convert the given volume of oxygen to moles.
Given volume of oxygen = 4.745 x 10^1 L
1 mole of oxygen gas = 22.4 L
Number of moles of oxygen = (Given volume of oxygen) / (1 mole of oxygen gas/22.4 L)
Step 2: Determine the stoichiometric ratio between phosphorus and oxygen.
From the balanced equation for the reaction given,
1 mole of phosphorus reacts with 5 moles of oxygen to form tetraphosphorus decaoxide (P4O10).
Step 3: Calculate the number of moles of phosphorus.
Since the stoichiometric ratio between phosphorus and oxygen is 1:5, the number of moles of phosphorus is related to the number of moles of oxygen. We can use this ratio to determine the moles of phosphorus.
Number of moles of phosphorus = (Number of moles of oxygen) x (1 mole of phosphorus / 5 moles of oxygen)
Step 4: Convert the moles of phosphorus to grams.
The molar mass of phosphorus (P4) is required to convert moles to grams.
Molar mass of phosphorus (P4) = (4 x Atomic mass of phosphorus)
Finally, using the calculated number of moles of phosphorus, we can multiply it by the molar mass of phosphorus to determine the mass of phosphorus reacted.
Mass of phosphorus reacted = (Number of moles of phosphorus) x (Molar mass of phosphorus P4)
By following these steps, you will be able to determine the grams of phosphorus that react with a given volume of oxygen at STP.