1. The combustion of acetylene is:
2 C2H2 + 5 O2 4 CO2 + 2 H2O ΔHo = -2511 kJ
11a. (5 pts) How much heat is produced if 85 g
C2H2 is combusted with excess O2?
The problem tells you that you obtain 2511 kJ heat for burning 2*26 or 52 g C2H2. Instead of using 52g the problem is using 85g so the heat produced must be
2511 kJ x (85/52) = ?
To find the amount of heat produced when 85 g of C2H2 is combusted with excess O2, we can use the given enthalpy change (ΔHo) for the combustion reaction.
The given enthalpy change is ΔHo = -2511 kJ, which corresponds to the combustion of 2 moles of C2H2.
First, we need to determine the number of moles of C2H2 in 85 g. To do this, we'll use the molar mass of C2H2.
The molar mass of C2H2 is:
(2 * atomic mass of C) + (2 * atomic mass of H) = (2 * 12.01 g/mol) + (2 * 1.01 g/mol) = 26.04 g/mol
Now, we can calculate the number of moles of C2H2:
Number of moles = mass / molar mass = 85 g / 26.04 g/mol
Next, we'll use stoichiometry to determine the amount of heat produced. From the balanced equation, we see that the combustion of 2 moles of C2H2 releases 2511 kJ of heat.
Since we have the moles of C2H2, we can set up a proportion to find the heat produced:
(85 g C2H2) * (1 mol C2H2 / 26.04 g C2H2) = x moles C2H2
(x moles C2H2) * (2511 kJ / 2 mol C2H2) = y kJ
Simplifying the equation:
x = (85 g) / (26.04 g/mol) = 3.273 moles C2H2
y = (3.273 moles C2H2) * (2511 kJ / 2 mol C2H2)
Calculating y:
y = 3.273 * (2511 / 2) = 4137.7835 kJ
Therefore, when 85 g of C2H2 is combusted with excess O2, approximately 4137.7835 kJ of heat is produced.