How many kilojoules are absorbed when 318 g of Ca(OH)2 reacts?

Ca(OH)2 = 74.09

65.3 kJ x (318/74.09) = ?

280.2726414

round to smallest SF
280

Reacts with what? What are the delta Hf values?

Ca(OH)2 -> CaO +H2O DeltaH = +65.3kj

Well, to calculate the exact amount of kilojoules absorbed, we need the balanced equation for the reaction. Without it, my crystal ball tells me that the answer is roughly "a bunch." But don't worry, it's not as big an energy 'absorber' as trying to understand quantum physics!

To determine the amount of energy (in kilojoules) absorbed when Ca(OH)2 reacts, we need to use the concept of enthalpy and a balanced chemical equation for the reaction.

1. First, we need to find the balanced chemical equation for the reaction involving Ca(OH)2. Let's assume it reacts with an acid, HCl, to form CaCl2 and water (H2O). The balanced equation is:

Ca(OH)2 + 2HCl → CaCl2 + 2H2O

2. Based on the balanced equation, we see that one mole of Ca(OH)2 reacts with 2 moles of HCl. So, we need to convert the mass of Ca(OH)2 (318 g) to moles.

To convert grams to moles, we use the molar mass of Ca(OH)2. The molar mass is the sum of the atomic masses of each element in the compound.

Ca(OH)2:
Ca: 40.08 g/mol
O: 16.00 g/mol (2 atoms)
H: 1.01 g/mol (2 atoms)

Molar mass of Ca(OH)2 = 40.08 + (16.00 * 2) + (1.01 * 2) = 74.10 g/mol

Now, we can calculate the number of moles of Ca(OH)2:
moles = mass / molar mass
moles = 318 g / 74.10 g/mol

3. Once we have the number of moles of Ca(OH)2, we need to find the enthalpy change (ΔH) for the reaction. The enthalpy change can either be given or obtained from a reference source.

4. Finally, we can calculate the amount of energy absorbed using the following equation:

Energy (in kilojoules) = ΔH (in kilojoules) * moles

By substituting the values we obtained, we can calculate the energy absorbed when 318 g of Ca(OH)2 reacts.