Question

What mass of propane (C3H8) is needed to produce 346 g carbon dioxide in the following reaction? A. 346 g C3H8 B. 1.86 g C3H8 C. 5075 g C3H8 D. 115 g C3H8

Answer 1

The answer to this question 116 g.

Answer 2

Answer : The correct option is, (D) 115 grams

Explanation :

Mass of
`CO_2` = 346 g

Molar mass of
`C_3H_8` = 44 g/mole

Molar mass of
`CO_2` = 44 g/mole

First we have to calculate the moles of
`CO_2`.

`\text{Moles of }CO_2=\frac{\text{Mass of }CO_2}{\text{Molar mass of }CO_2}=(346g)/(44g/mole)=7.86moles`

Now we have to calculate the moles of
`C_3H_8`.

The balanced chemical reaction is,

`C_3H_8+5O_2\rightarrow 3CO_2+4H_2O`

From the balanced reaction we conclude that,

As, 3 mole of
`CO_2` obtained from 1 mole of
`C_3H_8`

So, 7.86 moles of
`CO_2` react to give
`(1)/(3)* 7.86=2.62` moles of
`C_3H_8`

Now we have to calculate the mass of
`C_3H_8`.

`\text{Mass of }C_3H_8=\text{Moles of }C_3H_8* \text{Molar mass of }C_3H_8`

`\text{Mass of }C_3H_8=(2.62mole)* (44g/mole)=115.28g=115g`

Therefore, the mass of propane needed are, 115 grams