[help_me]

Water saturated with pure carbon dioxide at atmospheric pressure contains 0.15% by mass of dissolved CO₂.

Calculate the concentration, in mol dm^-3, of dissolved CO₂ in water, [CO₂ (aq)], which is in equilibrium with air containing 1% of carbon dioxide.

[Arkcon]

Greetings, help_me:, I'd like to welcome you and all the new students to the Chemical Forums.  But I'd like to as you to trouble yourself to read our Forum Rules{click}. You already accepted them when you signed up for our forum, and they apply to you, whether you agree with them or not, or even if you're unaware of them. 

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[help_me]

Firstly, I apologise for my immaturity as I was really desperate at that time.

What I did was to find the number of moles of carbon dioxide in 100g of the solution which was 0.00340909mol and I divided it by (99.85/1000) since 99.85 is the mass of water in cm³.
However I did not manage to get the correct answer which is 3.41 x 10^-4.

[Borek]

Are you sure when the air contains 1% of carbon dioxide water is saturated?

[help_me]

In that case, how do I calculate the concentration of carbon dioxide in air? Is it sufficient to find the concentration of carbon dioxide that is in equilibrium with air?

Also, does it mean that the information given on the % by mass of carbon dioxide saturated in water is unnecessary in this question?