# How can I figure this out?

1. May 7, 2006

### Mozart

I messed up in the lab a week or so ago, and was unable to do the lab properly. There was no time to restart so I am missing a crucial piece of data.

I need to know the mass of my calorimeter + the mass of a solution. I know the mass of the calorimeter, and I know the mass of the first component of the solution from an earlier step. All I need to know now is how much mass 50 ml of 2.00 mol/L Hydrochloric acid is in grams. I calculated that there would be 3.6 grams of HCl in the 50 ml so Is there any way to find out the volume of 3.6 grams of HCl now. I would know that the rest is water and be able to calculate its mass.

Can someone who has a lot of experience maybe estimate the mass that would be fine aswell. If worse comes to worse I'll just estimate that it weighs 60 grams. Does this sound reasonable?

Thanks.

2. May 7, 2006

### LeonhardEuler

A more reasonable approximation would be that the mass of the solution is 50g. You can see on this table
http://www.chembuddy.com/?left=CASC&right=density_tables
that the density of the solution hardly changes as the concentration of HCl is increased. The concentrations are given in percent weight in these tables, though. If you knew what the percent weight of HCL in your solution was exactly you wouldn't need the table, but it is about 3.6/50=7.2% and you can see that the density at this concentration is just barely above 1g/mL. (In case it throws you off too, scroll down to the bottom of the table where it explains that the different densities for pure water are due to the fact that the measurements were made at different temperatures.)

3. May 7, 2006

### Mozart

Thank you, I will be using 50 grams then. Thanks again.

4. May 7, 2006

### Staff: Mentor

51.654 g

Download CASC (concentration calculator) from my site - and try it (for free). Hydrochloric acid density table is built into the demo version. Start concentration calculator, select hydrochloric acid, enter volume, enter molar concentration, read mass. It can't be easier

CASC - concentration calculator

5. May 7, 2006

### Staff: Mentor

7.0587 %

1.0331 g/mL

CASC - concentration calculator