How many moles of H2O are needed to react with 15.0g of CaO forming Ca(OH)2?

0.267

To determine the number of moles of H2O needed to react with 15.0g of CaO, we need to set up a balanced chemical equation for the reaction.

The balanced chemical equation for the reaction between CaO and H2O to form Ca(OH)2 is:

CaO + H2O -> Ca(OH)2

From the equation, we can see that the mole ratio between CaO and H2O is 1:1. This means that for every 1 mole of CaO, we need 1 mole of H2O.

To calculate the number of moles of H2O needed, we can use the molar mass of CaO to convert grams of CaO to moles of CaO.

The molar mass of CaO is:

Ca = 40.08 g/mol
O = 16.00 g/mol

Adding the atomic masses gives us:

CaO = 40.08 g/mol + 16.00 g/mol = 56.08 g/mol

Now, we can calculate the number of moles of CaO:

moles of CaO = mass of CaO / molar mass of CaO
moles of CaO = 15.0 g / 56.08 g/mol
moles of CaO ≈ 0.267 mol

Since the mole ratio between CaO and H2O is 1:1, the number of moles of H2O needed is also approximately 0.267 mol.

To determine the number of moles of H2O needed to react with 15.0g of CaO, we need to use stoichiometry.

The balanced chemical equation for the reaction is:

CaO + H2O → Ca(OH)2

From the equation, we can see that for every 1 mol of CaO, 1 mol of H2O reacts to form 1 mol of Ca(OH)2.

1. First, calculate the molar mass of CaO and H2O.

The molar mass of CaO is 40.08 g/mol (Ca: 40.08 g/mol, O: 16.00 g/mol).

The molar mass of H2O is 18.02 g/mol (H: 1.01 g/mol x 2, O: 16.00 g/mol).

2. Convert the given mass of CaO to moles.

Moles of CaO = Mass of CaO / Molar mass of CaO
= 15.0 g / 40.08 g/mol
≈ 0.374 mol

3. Since the stoichiometry in the balanced equation shows a 1:1 ratio between CaO and H2O, the number of moles of H2O required will also be 0.374 mol.

Therefore, 0.374 moles of H2O are needed to react with 15.0 grams of CaO and form Ca(OH)2.

Here is a solved example of a stoichiometry problem.

http://www.jiskha.com/science/chemistry/stoichiometry.html