[Asum]

A question from an old exam:

Methan has lower- and upper flammability boundries at 5 % and 15 % respectively.
How many liters of air must be mixed with 1 liter of Methan to get a flammable solution?

Don't know how to answer this.

(sorry if it's poorly worded, its translated from another language)

[sjb]

A question from an old exam:

Methan has lower- and upper flammability boundries at 5 % and 15 % respectively.
How many liters of air must be mixed with 1 liter of Methan to get a flammable solution?

Don't know how to answer this.

(sorry if it's poorly worded, its translated from another language)

First thing perhaps. Can you write a balanced equation for the combustion?

[Borek]

No need for reaction equation. You start with 100% methane, it won't burn till the methane concentration in the mixture falls down to 15% (upper limit; you can dilute more, down to a lower limit, but question most likely asks for a minimum amount of air). Write formula for % concentration of methane in mixture, assume it equals 15%, solve for the volume of air.