Question

Read the given chemical reaction.

C2H6 + O2 → CO2 + H2O

How many moles of O2 are required to react completely with 3.2 moles of C2H6?

a 3.5 moles of O2

b 6.5 moles of O2

c 10.4 moles of O2

d 11.2 moles of O2

Answer 1

$\qquad \qquad\huge \underline{\boxed{\sf Answer}}$

First of all, balance the equation ~

$\sf \quad \: 2 C_2H_6 + 7O_2 = 4CO_2 + 6H_2O$

If we use 2 moles of Ethane we have use 7 moles of Oxygen gas,

So ~

$\qquad \sf  \dashrightarrow \: \sf2 \: moles\: C_2H_6 = 7 \: moles \: O_2$

$\qquad \sf  \dashrightarrow \: \sf1 \: moles\: C_2H_6 = \frac{7}{2} \: moles \: O_2$

$\qquad \sf  \dashrightarrow \: \sf 3.2 \: moles\: C_2H_6 = ( \frac{7}{2} \times 3.2) \: moles \: O_2$

$\qquad \sf  \dashrightarrow \: \sf 3.2 \: moles\: C_2H_6 = ( 7 \times 1.6) \: moles \: O_2$

$\qquad \sf  \dashrightarrow \: \sf 3.2 \: moles\: C_2H_6 = 11.2\: moles \: O_2$

so, for reaction with 3.2 moles of ethane we need 11.2 moles of Oxygen gas .

Hence, correct choice is D