The reaction cao(s)+ h2o(> ca(oh)2 delta h= -65.2 kj

how much energy will be released if 500.0g of cao is reacted

There is 582 kJ of energy released. Δ H rxn  for 500g=  −  582 kJ  ( negative because the energy is released).

Explanation:

Step 1: The balanced equation

CaO(s)+ H2O(l) → ca(OH)2     ΔH= -65.2 kJ

In this situation, 1 mole of CaO consumed, needs 1 mole of H2O to produce 1 mole of Ca(OH)2

The enthalpy change of this reaction is  Δ H rxn =  −  65.2 kJ

This means the reaction gives off  65.2 kJ  of heat when 1 mole of CaO and 1 mole of H2O react.

Step 2: Calculate number of moles in 500 g of CaO

Number of moles = mass of CaO / Molar mass of CaO

Number of moles = 500 grams / 56.077 g/mol = 8.92 moles

Step 3: Calculate energy released

Since there is released 65.2 kJ when 1 mole of CaO reacts; for 8.92 moles of CaO there will be released 8.92 * 65.2 kJ = 581.584 ≈ 582 kJ

.

There is given off 582 kJ of energy

Δ H rxn  for 500g=  −  582 kJ

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

it's filtration, but this is an assumption so my apologies if i got this