In the atom model, the poppy seeds are placed in different places to represent the different position of electrons.
The enthalpy change of the reaction is <u>-1347.8 kJ.</u>
<h3>What is the enthalpy change, ΔH, of the reaction?</h3>
The enthalpy change, ΔH, of the reaction is calculated from Hess's law of constant heat summation as follows:
Hess's law states that the enthalpy change of a reaction is the sum of the enthalpies of the intermediate reaction.
Given the reactions below and their enthalpy values;
1. X (s) + 12 O₂ (g)⟶ XO (s) ΔH₁ = −850.5 kJ
2. XCO₃ (s) ⟶ XO (s) + CO₂ (g) ΔH₂ = +497.3 kJ
The enthalpy change, ΔH, of the reaction whose equation is given below, will be:
X (s) + 12 O₂ (g) + CO₂ (g) ⟶ XCO₃ (s)
ΔH = ΔH₁ - ΔH₂
ΔH = − 850.5 kJ - (+497.3 kJ)
ΔH = -1347.8 kJ
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Answer:
Chromium
Explanation:
Cr has 24 atomic number and mass number 52
Answer:
pH = 12.2
Explanation:
Given data:
Mass of lime = 0.69 g
Volume = 1535 mL (1535 / 1000 = 1.535 L)
pH of solution = ?
Solution:
First of all we will determine the molarity.
Molarity = moles of solute / volume in litter
Number of moles = mass / molar mass
Number of moles = 0.69 g / 56.1 g/mol
Number of moles = 0.0123 mol
Molarity = moles of solute / volume in litter
Molarity = 0.0123 mol / 1.535 L
Molarity = 0.008 M
One mole of CaO neutralize two mole of OH⁻.
0.008 M×2 = 0.016 M
[OH⁻] = 0.016 M
pOH = -log [OH⁻]
pOH = [0.016]
pOH = 1.8
14 = pH +pOH
pH = 14 - pOH
pH = 14-1.8
pH = 12.2