2 more chem questions that im not sure about

[macman2790]

here it is:

Consider the balanced chemical equation: Ca(OH)2(aq) + 2HCl(aq) → CaCl2(aq) + 2H2O(l). How many moles of HCl remain if 0.1 mol of Ca(OH)2 react with 0.4 mol of HCl?


i think the answer is 0.3 mol, but im not sure

also im not so sure about this one, if anyone gets a chance.

A flask contains pure Ne at a pressure of 0.50 atm. If Ar is added to the flask until there is three times as much Ar as Ne, the total pressure in the flask is:

thanks

 

[Abstract]

Are you going to ask us about every chemistry question you have?

 

[Hummer]

Try putting them all in one thread like I did.

 

[macman2790]

Are you going to ask us about every chemistry question you have?

no, im just in a hurry, sorry i have too many and this are the last 2 i have questions on

 

[Jasonbot]

Well the ratio is 1:2 so the limiting reagent is the HCl and so the Ca(OH)2 reacts fully but only 0.2 moles of HCl will react. Therefore 0.1+(0.1*2)=0.3 moles that react completely and so 0.2 moles DO NOT react.

I can't remember the formula for volume now, I think it's n=m/V

remember pressure is always a ratio as in P1/V1=P2/V2
so:
0.5/V1=P2/V2

But please remember I'm unsure of the equation to find V (sorry)...