Question

M (CaO)-2.8 г m (Ca (OH)2)-? CaO+H2O=Ca (OH)2

Answer 1

Ответ:

CaO+H2O=Ca(OH)2

2,8Г-Х

56Г{Ar(Ca)=40  + Ar(O)=16} -74Г(Mr Ca(OH)2)

X=3,7Г

Answer 2

The molar mass of calcium oxide (CaO) is approximately 56.08 grams per mole, while the molar mass of calcium hydroxide (Ca(OH)2) is approximately 74.09 grams per mole.

To calculate the mass of calcium hydroxide (m(Ca(OH)2)) formed when 2.8 grams of calcium oxide (m(CaO)) reacts with water (H2O) to form calcium hydroxide (Ca(OH)2), we need to set up a balanced equation and use stoichiometry.

The balanced equation for the reaction is:

CaO + H2O -> Ca(OH)2

From the balanced equation, we can see that 1 mole of CaO reacts with 1 mole of H2O to produce 1 mole of Ca(OH)2.

To determine the number of moles of CaO, we divide the mass of CaO by its molar mass:

n(CaO) = m(CaO) / M(CaO) = 2.8 g / 56.08 g/mol ≈ 0.05 mol

Since the stoichiometry of the reaction tells us that the ratio of moles of CaO to moles of Ca(OH)2 is 1:1, the number of moles of Ca(OH)2 formed is also 0.05 mol.

To calculate the mass of Ca(OH)2, we multiply the number of moles of Ca(OH)2 by its molar mass:

m(Ca(OH)2) = n(Ca(OH)2) * M(Ca(OH)2) = 0.05 mol * 74.09 g/mol = 3.705 g

Therefore, when 2.8 grams of CaO reacts with water to form Ca(OH)2, the mass of Ca(OH)2 formed is approximately 3.705 grams.