Chemistry help please!!?

Question

how do you calculate concentrations of diluted solutions?
if you don't know this.. please tell me as much as you know on acid and bases

Answer 1

Start with 10 M HCl

OK dilute it by 10% (in other words make a 9M HCL solution)

how much 10M HCL do I need to add to a liter of solution to make 1 liter 9M HCl

xL*10M = 9M ==> xL = 9/10liter 1000ml/liter= 900 ml

take 900 ml of 10 MHCl and dilute until the volume is 1000ml

Harder:

if 234 ml of 3.2 M HCL M is diluted to 625 ml what is the dilution factor?

first figure out the concentration of the final solution:
.234L*(3.2Mole/L)/.625L = 1.19 M HCl

3.2/1.1*100 = 26.8%

The exact same reasoning applies to bases....

Answer 2

If you have an acid (for example) solution with molarity of M and a volume of Vo and you add second volume of Vd which has no acid, the new molarity will be M x Vo/(Vo+Vd)

The oldest definition of an acid is that it supplies H+ when it is added to water and that a base supplies OH- when added to water. STRONG acids and bases totally "break up" in water, so the H+ in a solution to which acid is added is given by the above relation where M is the concentration of the added acid, Vo is the volume of the added acid, and Vd is the volume of the initial solution. WEAK acids "break-up" to a smaller extent, and to find the H+ in a solution of the weak acid, you need to know the Ka of the acid or the Kb of the base.

Other definitions of acids and bases came about because chemists worked in non-water systems and noted similar behavior. For example, in liquid ammonia, ammonium compounds would be acids and amide compounds (like NaNH2, or sodamide) would be bases.

That ought to keep you going for a while.

Answer 3

Normaly concentration is
=(number of moles/volume of solution)
volume should be in liters for convenience.

if you know the number of moles you have, and you know the volume in which they are dissolved then divide as above.

if instead you have the mass of the substance then you have to divide this mass by Mr of the substance to get the number of moles to use in the previous equations.
however when diluting solutions, you have to use the idea of morarity. 1M means one mole per liter of solution. here are some concepts:

You dilute a solution whenever you add solvent to a solution. Adding solvent results in a solution of lower concentration. You can calculate the concentration of a solution following a dilution by applying this equation:

MiVi = MfVf

where M is molarity, V is volume, and the subscripts i and f refer to the initial and final values.

Example:
How many millilieters of 5.5 M NaOH are needed to prepare 300 mL of 1.2 M NaOH?

Solution:
5.5 M x V1 = 1.2 M x 0.3 L
V1 = 1.2 M x 0.3 L / 5.5 M
V1 = 0.065 L
V1 = 65 mL

Answer 4

i can't understand your question. sorry, i think i still remember a few and i'll understand your question if you give an example to you it. =)