Calculate the heat released when 4 L Cl2 with a density of 2.46 g/L at 25 degrees C reacts with an excess of sodium to form solid sodium chloride at 25 degrees C.
I think you want the Born-Haber cycle but you don't have any of the information. Here is a site that you can read about it. http://en.wikipedia.org/wiki/Born%E2%80%93Haber_cycle
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To calculate the heat released during the reaction, we need to apply the concept of heat of reaction or enthalpy change (ΔH) to the balanced chemical equation.
First, let's write the balanced chemical equation for the reaction between chlorine gas (Cl2) and sodium metal (Na) to form sodium chloride (NaCl):
2Na + Cl2 → 2NaCl
The stoichiometric ratio shows that 1 mole of Cl2 reacts with 2 moles of Na to produce 2 moles of NaCl.
Next, we need to calculate the number of moles of Cl2 involved in the reaction.
Given that the density of Cl2 is 2.46 g/L, we can calculate the mass of Cl2:
Mass = Density × Volume
Mass = 2.46 g/L × 4 L
Mass = 9.84 g
Now, let's convert the mass of Cl2 to moles using its molar mass. The molar mass of Cl2 is 35.45 g/mol.
Moles = Mass / Molar Mass
Moles = 9.84 g / 35.45 g/mol
Moles = 0.277 mol
Since the reaction is with an excess of sodium, we can assume that all the moles of Cl2 will react. Therefore, we have 0.277 moles of Cl2 reacting.
To calculate the heat released during the reaction, we need to consult the standard enthalpy of formation (ΔHf) values. The ΔHf of NaCl is -411.2 kJ/mol.
Since 0.277 mol of Cl2 reacts to produce 0.277 mol of NaCl (due to the 1:2 stoichiometric ratio), the heat released can be calculated as follows:
Heat Released = ΔHf × Moles
Heat Released = -411.2 kJ/mol × 0.277 mol
Heat Released ≈ -113.89 kJ (rounded to two decimal places)
Therefore, the heat released when 4 L of Cl2 reacts with an excess of sodium to form solid sodium chloride at 25 degrees Celsius is approximately -113.89 kJ. Note the negative sign indicating the release of heat during the reaction.