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# Chemistry Applying Mole Concept Combustion Questions in Mobile Legends

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See how H2 Chemistry Mole Concept Combustion Questions can be applied in games:

## Question

In order to develop a new skill, Valir sparked 20 cm3 of a gaseous hydrocarbon with 150 cm3 of oxygen and the residual gases cooled to room temperature, a contraction of 60 cm3 occurred. A further contraction of 80cm3 took place when the residual gases were subjected to aqueous NaOH. Find formula of the hydrocarbon Valir used. [All gaseous volumes are measured under identical conditions.]

## Solution

CxHy + (x + $\frac{y}{4})$ O2 $\rightarrow$ CO2 + H2O

V(CO2) produced = 80 cm3 since it is removed by alkaline NaOH.

$\frac{V(CO_2)}{V(C_xH_y)} = \frac{80}{20} = \frac{x}{1} \Rightarrow x = 4$

Total initial volume before combustion = 150 + 20 = 170 cm3

Since a contraction of 60cm3 occurred after ignition and cooling, contraction = total initial volume – total final volume

V(O2) excess + V(CO2) = 170 – 60 = 110 cm3.

V(O2) excess = 110 – 80 = 30 cm3

V(O2) reacted = 150 – 30 = 120 cm3

$\frac{V(O_2)_{reacted}}{V(C_xH_y)} = \frac{120}{20} = \frac{x+\frac{y}{4}}{1} = \frac{4+\frac{y}{4}}{1} \Rightarrow$ y = 8

The molecular formula used by Valir is C4H8.