[harvester of sorrow]

I'm trying to calculate the solution enthalpy change from when C₆H₈O₇ reacts with NaHCO₃.
There was 5 mL of each, and I know the molar masses are 192.1 g/mole and 84.0 g/mole, respectively.
Is there some way I can calculate the mass (or how many moles there are) of the different substances?

[Borek]

Density is a link between mass and volume, and it is usually found in tables.

But somehow I feel like there is some kind of confusion behind the question. Can you describe the procedure and details of what you did? Have you used 5 mL of a solid, or a pure liquid, or solution?

Are you aware of the fact C₆H₈O₇ means nothing - there are many compounds with this formula?

[harvester of sorrow]

The C₆H₈O₇ compound is citric acid (but the molar mass would be the same for all compounds, right?), and it was 5 mL of the solids (a teaspoon).

[fledarmus]

It is very difficult to predict the mass of a solid from the volume in the way that you measured it. The solids are by nature irregular, and you have no idea how much of the volume was deadspace, empty air space between particles of solid. If you still have access to the teaspoon and the solids, the best choice would be to simply weigh out a teaspoonful of the solid, and just assume you were consistent enough to get relatively close to the same weight each time. The densities you will find in tables refer to the density of a solid mass of the material, not a crushed powder.

If you can't weigh the powder at this point, about all you can do is assume there was no airspace between the grains of the powder and look up the density of your solids. Then, since density is mass/volume, and you know the volume (roughly), you can calculate the mass (roughly).

[harvester of sorrow]

Never mind, think I found it..