Determine the mass of oxygen that is needed to react with 33 grams of phosphorus. 4P + 5 02 → 2 P205
A
27.3 grams O2
B
1.33 grams 02
С
213 grams 02
oo
42.6 grams 02

D = Mass =  42.6 g

Explanation:

Given data:

Mass of phosphorus react = 33 g

Mass of oxygen needed = ?  

Solution:

Chemical equation:

4P + 5O₂     →      2P₂O₅

Number of moles of phosphorus:

Number of moles = mass/molar mass

Number of moles = 33 g/ 30.97 g/mol

Number of moles = 1.065 mol  

now we will compare the moles of phosphorus and oxygen.  

               P         :       O₂  

               4         :        5  

        1.065        :        5/4×1.065 = 1.33mol

Mass of oxygen needed:

Mass = number of moles × molar mass

Mass = 1.33 mol × 32 g/mol  

Mass = 42.6 g

Thus, 43.6 g of oxygen needed to react with 33 g of phosphorus.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).