For solution 1, 4.00mL of 0.0200 M Cr(NO)3 was added to 20.00ml of 0.0200 M Na2H2EDTA, then the a time and absorbance were taken every 5 mins.
If at 5:00 min the absorbance was 0.039 how do I find [Cr3+]0, [CrEDTA-]t, and [Cr3+]t.
The absorbance at 0:00 mins was 0.039 if it is needed.
Thanks!
To find [Cr3+]0, [CrEDTA-]t, and [Cr3+]t, we need to use the information given and apply the principles of stoichiometry and the Beer-Lambert Law.
1. Finding [Cr3+]0:
We know that the initial volume of Cr(NO)3 added is 4.00 mL, and its concentration is 0.0200 M. To find the initial concentration of Cr3+, we use the equation:
[Cr3+]0 = (concentration of Cr(NO)3 * volume of Cr(NO)3 added) / final volume
= (0.0200 M * 4.00 mL) / (20.00 mL + 4.00 mL)
= (0.0200 M * 4.00 mL) / 24.00 mL
= 0.00333 M
So, [Cr3+]0 is 0.00333 M.
2. Finding [CrEDTA-]t:
From the reaction:
Cr(NO)3 + Na2H2EDTA -> CrEDTA + 2NaNO3 + 2H2O
We can see that the stoichiometric ratio between Cr(NO)3 and CrEDTA is 1:1. At 0:00 min, the absorbance is given as 0.039. According to the Beer-Lambert Law, the absorbance (A) is related to the concentration (C) of a substance by the equation:
A = ε * C * l
Where ε is the molar absorptivity (a constant), C is the concentration, and l is the path length (constant).
Assuming the path length is constant, we can rearrange the equation to find the concentration:
C = A / (ε * l)
Given that the absorbance (A) at 0:00 min is 0.039, and assuming the molar absorptivity (ε) and path length (l) are constants, we can substitute these values into the equation to find [CrEDTA-]t.
3. Finding [Cr3+]t:
To find [Cr3+]t at a specific time, we need the absorbance and apply the Beer-Lambert Law. The equation is the same as in step 2:
A = ε * C * l
Given the absorbance (A) at a particular time, we can rearrange the equation to find the concentration (C):
C = A / (ε * l)
Substitute the given absorbance at the specific time into the equation to find [Cr3+]t.
Please provide the values for the molar absorptivity (ε) and path length (l) to calculate the concentrations [CrEDTA-]t and [Cr3+]t at a specific time.