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The molecular formula of the liquid : C₆H₁₂
<h3>Further explanation</h3>
Given
molar ratio C H = 1.2 : 0.12
0.12 g at STP gave 32 cm³(0.032 L)
Required
The molecular formula
Solution
At STP, 1 mol = 22.4 L, so for 0.032 L :
mol = 0.032 : 22.4
mol = 0.00143
Molar mass (M) of liquid :
M = mass : mol
M = 0.12 g : 0.00143 mol
M = 83.92≈84 g/mol
C : H = 1 : 2
(CH₂)n=84
(12+2.1)n=84
(14)n=84
n=6
(CH₂)₆=C₆H₁₂
Answer:
The correct answer is - 13.33 kJ of heat
Explanation:
To know which one is the limiting reagent, determine the number of moles of each reagent in order .
n(K) = mass/atomic weight = 1.41/39 = 0.036 moles
Density of ICl = Mass/Volume
3.24 = Mass/6.52
Mass of ICl = 21.12 g
n(ICl) = mass/molar mass = 21.12/162.35 = 0.130 moles
2 moles of K reacts with 1 mole of ICl
0.036 moles of K will react with = 0.036/2 = 0.018 moles of ICl
since the amount of moles of ICl is more than 0.018, it is in excess and hence K is the limiting reagent. Now, use the balance equation to determine the amount of heat liberated:
2 moles of K gives out -740.71 kJ of heat
1 mole of K will give out = -740.71/2 = 370.36 kJ of heat
0.036 moles of K will give out = 0.036 × 370.36 = 13.33 kJ of heat
Thus, the correct answer is - 13.33 kJ of heat
