What mass of H₂O is formed when excess H₂ reacts with 64 g of O₂? *

2H2+O2 - ->2H2O

Answer: 72g

72g of H2O.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

2H2 + O2 - >2H2O

Next, we'll determine the mass of O2 that reacted and the mass of H2O produced from the balanced equation.

This is illustrated below:

Molar Mass of O2 = 16x2 = 32g/mol

Molar Mass of H2O = (2x1) + 16 = 18g/mol

Mass of H2O from the balanced equation = 2 x 18 = 36g

Summary:

From the balanced equation above,

32g of O2 reacted to produce 36g of H2O.

Now, we can obtain the mass of H2O produced when 64g of O2 react as follow:

From the balanced equation above,

32g of O2 reacted to produce 36g of H2O.

Therefore, 64g of O2 will react to produce = (64 x 36) / 32 = 72g of H2O.

From the calculations made above, 72g of H2O is produced from the reaction.