Calculate the number of grams of sodium oxide that will be produced when 115g of sodium react with oxygen.

Mass = 154.95 g

Explanation:

Given data:

Mass of sodium react = 115 g

Mass of sodium oxide formed = ?

Solution:

Chemical equation:

4Na + O₂        →     2Na₂O

Number of moles of sodium:

Number of moles = mass/molar mass

Number of moles = 115 g/ 23 g/mol

Number of moles = 5 mol

Now we will compare the moles of sodium and sodium oxide.

                Na         :          Na₂O

                  4          :             2

                   5         :          2/4×5 = 2.5 mol

Mass of sodium oxide:

Mass = number of moles × molar mass

Mass = 2.5 mol ×  61.98 g/mol

Mass = 154.95 g

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.