Need help with acid calculations.

[jordehwa]

So i my question is, How can I calculate how much acid is needed to fully react with a metal or compound, instead of just using excess acid?

 

For example like if you needed to dissolve 10 grams of zinc how could you calculate how much hcl is needed, so you dont ad too little or too much acid?

 

Please give me an example and explain. Thanks B)

Edited December 8, 2010 by jordehwa

[mississippichem]

First set up a balanced equation to give the correct mole ratios. Then you can convert to grams after you know how many grams of Zn you are using. Then either you'll know the density of the HCl you are using (different for different concentrations) or you can measure it. Use density to solve for volume of HCl needed.

 

A different example:

 

[ce] 2Na_{(s)} + 2H_{2}O_{(l)} -> 2NaOH_{(aq)} + H_{2}_{(g)}[/ce]

 

[math]\left(\frac {mol Na}{1}\right)\times \left(\frac{ mol H_{2}O}{ mol Na}\right)\times\left(\frac{18.02 g\cdot mol^{-1} H_{2}O}{ mol H_{2}O}\right)=gH_{2}O [/math]

 

[math]density=\frac{mass}{volume}[/math]

 

[math]mL H_{2}O=\frac{gH_{2}O}{g{\cdot}mL^{-1}H_{2}O}[/math]

 

This is a totally different problem that doesn't involve an acid but the math is still valid in your case.

[jordehwa]

thanks for the reply.

 

I still want to do some more reasearch on this. I'm not in college, I'm in home school so is there a website where I can do some more reasearch on this subject?

 

By the way whats this kind of problem called in chemistry?

Edited December 9, 2010 by jordehwa

[mississippichem]

A conversion, or mole ratio problem. If you had given me the masses of the two substances instead of asking how much you needed, it would've been a limiting reagent problem.