Say there is a diluted solution and we need to find the final concentration of it, using the equation M1V1 = M2V2.
Does this method change, if the compound (concentration that we're trying to find), is in a solution that has already reacted with another compound?
Ex: CaCO3 + HCl
Then, after it's diluted.
If it does can you tell me how to find the concentration?
To find the final concentration of a compound in a diluted solution that has already reacted with another compound, we can use the same equation, M1V1 = M2V2.
Let's break it down step by step:
Step 1: Write the balanced chemical equation for the reaction. In this case, the reaction is between calcium carbonate (CaCO3) and hydrochloric acid (HCl), resulting in the formation of calcium chloride (CaCl2), carbon dioxide (CO2), and water (H2O).
CaCO3 + 2HCl -> CaCl2 + CO2 + H2O
Step 2: Determine the initial molar concentration and volume of the solution that has reacted. Let's say we start with a known volume of 100 mL of 1 M hydrochloric acid.
M1 = 1 M (initial concentration of HCl)
V1 = 100 mL (initial volume of HCl)
Step 3: Determine the final volume of the solution after dilution. We need to know the volume of the resulting solution after the reaction and dilution have taken place. Let's say the final volume is 250 mL.
V2 = 250 mL (final volume after dilution)
Step 4: Use the molar ratio from the balanced chemical equation to determine the final concentration of the compound we're interested in. In this case, we want to find the concentration of calcium chloride (CaCl2), which is formed by the reaction.
From the balanced equation, we see that 1 mole of CaCO3 reacts with 2 moles of HCl to produce 1 mole of CaCl2. Therefore, we have a 1:1 molar ratio between CaCO3 and CaCl2.
M2 = M1 x (V1/V2)
= 1 M x (100 mL / 250 mL)
= 0.4 M
So, the final concentration of calcium chloride (CaCl2) in the solution, after dilution, is 0.4 M.
Remember, this method assumes the reaction between CaCO3 and HCl goes to completion, and the final solution is well mixed. Additionally, other factors, such as temperature and pressure, may also influence the reaction and concentration.