Si(s)+ 2Cl2(g) --> SiCl2(g) --> SiCl2(l) + 687 kJ. How much heat is produced when 106 grams of Cl2 react?
To calculate the amount of heat produced when 106 grams of Cl2 react, we need to use the given equation:
Si(s) + 2Cl2(g) → SiCl2(g)
The enthalpy change for the reaction is ΔH = -687 kJ.
First, we need to determine the molar mass of Cl2. The molar mass of Cl is approximately 35.45 g/mol, so the molar mass of Cl2 is 2 x 35.45 g/mol = 70.9 g/mol.
Next, we need to calculate the number of moles of Cl2 in 106 grams:
Number of moles = Mass / Molar mass
Number of moles = 106 g / 70.9 g/mol = 1.49 mol
According to the balanced equation, the reaction produces 687 kJ of heat per 2 moles of Cl2. Therefore, we can create the following ratio:
(687 kJ / 2 mol) = (x kJ / 1.49 mol)
Now, we can solve for x:
x = (687 kJ / 2 mol) x (1.49 mol) ≈ 511.5 kJ
Thus, approximately 511.5 kJ of heat is produced when 106 grams of Cl2 react.
To determine the amount of heat produced when 106 grams of Cl2 react, we need to use the given balanced chemical equation and the molar mass of Cl2.
1. Calculate the number of moles of Cl2:
- The molar mass of Cl2 is approximately 71 g/mol (chlorine has a molar mass of 35.5 g/mol, and there are two chlorine atoms in Cl2).
- Divide the given mass (106 grams) by the molar mass of Cl2 to get the number of moles.
106 g Cl2 / 71 g/mol = 1.496 moles Cl2 (rounded to 3 decimal places)
2. Use the stoichiometry of the balanced chemical equation to find the moles of SiCl2 and the associated heat produced:
- According to the balanced equation, 1 mole of SiCl2 is formed for every 2 moles of Cl2 that react.
- Therefore, the number of moles of SiCl2 formed is half of the moles of Cl2.
Moles of SiCl2 = 1.496 moles Cl2 / 2 = 0.748 moles SiCl2 (rounded to 3 decimal places)
3. Apply the given heat change per mole of SiCl2:
- The given reaction produces 687 kJ of heat for every 1 mole of SiCl2 formed.
- Multiply the moles of SiCl2 by the heat change to get the total amount of heat produced.
Heat produced = 0.748 moles SiCl2 * 687 kJ/mol = 507.876 kJ (rounded to 3 decimal places)
Therefore, when 106 grams of Cl2 react, approximately 507.876 kJ of heat is produced.
You get 687 kJ for 28.085 g Si; therefore,
687 kJ x (106/28.085) = ??