Question

15.0 g of Calcium reacts with excess Oxygen gas to form Calcium Oxide 2Ca + O2 -> 2CaOif the percent yield is 77% what mass of CaO is produced by the rection.

Answer 1

Step-by-step explanation

Given

Mass of Calcium = 15.0 g

we know the molar mass of Ca = 40,078 g/mol, CaO = 56,0774 g/mol

Solution

Step 1: Fine the moles of Ca

n = m/M where n is the moles, m is the mass and M is the molar mass

n = 15.0g/40.078g/mol

n = 0.374 mol

Step 2: Use stoichiometry to find the moles of CaO

The molar ratio between Ca and CaO is 2:2

Therefore the number of moles of CaO = 0.374 mol

Step 4: Find the theoretical mass of CaO

m = n x M

m = 0.374 mol x 56,0774 g/mol

m = 6.674x10^-3 g

%yield = (actual yield/theoretical yield) x 100

0.77 = actual yield/6.674x10^-3

Actual yield = 5.14x10^-3 g

Answer

Mass of CaO = 5.14x10^-3 g