Above is a potential energy curve of a reaction. It depicts conversion of reactant to product via transition state.
When a catalyst is added to the reaction system, energy barrier of reaction decreases.
It must be noted that energy barrier reaction is defined as energy difference between reactant and transition state.
In present case, energy of reactant is 200 kj, while that of transition state (in absence of catalyst) is 650 kj
Thus, energy barrier of reaction is 650 - 200 = 450 kj
<span>Hence, system must absorb 450 kj of energy for the reaction to start, if no catalyst was used</span>
Answer:
Mass = 53.45 g
Explanation:
Given data:
Mass of propane = 200 g
Mass of S₂ = 75 g
Theoretical yield /Mass of CS₂ = ?
Solution:
Balanced Chemical equation:
C₃H₈ + 5S₂ → 4H₂S + 3CS₂
Number of moles of propane:
Number of moles = mass / molar mass
Number of moles = 200 g/ 44.1 g/mol
Number of moles = 4.54 mol
Number of moles of S₂:
Number of moles = mass / molar mass
Number of moles = 75 g/ 64.14 g/mol
Number of moles = 1.17 mol
Now we will compare the moles of carbon disulfide with both reactant.
S₂ : CS₂
5 : 3
1.17 : 3/5×1.17 = 0.702
C₃H₈ : CS₂
1 : 3
4.54 : 3×4.54 = 13.62 mol
Number of moles of CS₂ produced by S₂ are less so it will limiting reactant and limit the yield of carbon disulfide.
Theoretical yield of carbon disulfide.
Mass = number of moles ×molar mass
Mass = 0.702 mol × 76.14 g/mol
Mass = 53.45 g
First you need to find out the Limiting reactant (LR). convert both reactants to the same thing. Check that the chemical equation is balanced. Now use stoichiometr and remember at moles, multiply: need moles, divide2 g / 42g/mol= 0.0477 mol propane mass propane/ Molar Mass propane = moles propane4 g / 32 g/mol= 0.125 mol oxygen X (1 mol/ 5 mol) = 0.025 mol propane oxygen is the LRmass O2 / MM O2 X (mol propane / mol O2)0.025 mol X (3 mol / 1 mol ) = .075 mol CO20.075 mol X (12 + 2*16) g /mol = 3.6 g CO2 In one step:2 g / 42g/mol X (3 mol / 1 mol ) X 48 g/mol = 6.86 g CO24 g / 32 g/mol X (3 mol / 5 mol ) X 48 g/mol = 3.6 g CO2mass/ MM X coefficient ratio X MM (new)
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