Trial 1 — Reaction with 0.10 M NaOH
Enter Time (s) and Absorbance data manually below, or upload an .xls/.xlsx file. ln(ABS) and 1/ABS are calculated automatically.
No file loaded
Graphs
ABS vs. Time (Zero Order)
ln(ABS) vs. Time (First Order)
1/ABS vs. Time (Second Order)
R² Values (Linearity Test)
ABS vs. Time (Zero Order)
—
ln(ABS) vs. Time (First Order)
—
1/ABS vs. Time (Second Order)
—
Based on the data, the reaction order is: —
Time-Series Data Entry
Trial 2 — Reaction with 0.20 M NaOH
Enter Time (s) and Absorbance data manually below, or upload an .xls/.xlsx file. ln(ABS) and 1/ABS are calculated automatically.
No file loaded
Graphs
ABS vs. Time (Zero Order)
ln(ABS) vs. Time (First Order)
1/ABS vs. Time (Second Order)
R² Values (Linearity Test)
ABS vs. Time (Zero Order)
—
ln(ABS) vs. Time (First Order)
—
1/ABS vs. Time (Second Order)
—
Based on the data, the reaction order is: —
Time-Series Data Entry
Determine CV Reaction Order
| Trial |
NaOH Conc. |
Determined Order |
| Trial 1 |
0.10 M |
— |
| Trial 2 |
0.20 M |
— |
Waiting on data from both trials.
Pseudo Rate Law
The pseudo rate law for the fading of Crystal Violet with excess NaOH is:
Rate = k′ [CV]n
where k′ = k [OH⁻]x
Pseudo Rate Constants (k′)
k′ equals the negative slope of the best-fit line for ln(ABS) vs. Time (first-order plot).
| Trial |
[NaOH] Stock |
Slope of ln(ABS) vs. t |
k′ (s⁻¹) |
| Trial 1 |
0.10 M |
— |
— |
| Trial 2 |
0.20 M |
— |
— |
Dilution Setup — [OH⁻] After Mixing
Volume of Crystal Violet added (mL)
Volume of NaOH added (mL)
[OH⁻] for Trial 1 after dilution (M)
—
[OH⁻] for Trial 2 after dilution (M)
—
Determine OH⁻ Reaction Order (x)
Dividing the two pseudo rate constant equations:
k′₁ / k′₂ = ([OH⁻]₁ / [OH⁻]₂)x
⟹ x = log(k′₁/k′₂) / log([OH⁻]₁/[OH⁻]₂)
| Quantity |
Value |
| k′₁ / k′₂ | — |
| [OH⁻]₁ / [OH⁻]₂ | — |
| x (calculated) | — |
| x (rounded) | — |
Order with respect to OH⁻: —
Determine Rate Constant (k)
Using k = k′ / [OH⁻]x for each trial, then averaging.
| Trial |
[OH⁻] diluted (M) |
k′ (s⁻¹) |
x |
k (L mol⁻¹ s⁻¹) |
| Trial 1 |
— |
— |
— |
— |
| Trial 2 |
— |
— |
— |
— |
Cumulative Summary
Trial 1 — 0.10 M NaOH
—
Reaction order w.r.t. CV
— s⁻¹ (k′)
— L mol⁻¹ s⁻¹ (k)
Trial 2 — 0.20 M NaOH
—
Reaction order w.r.t. CV
— s⁻¹ (k′)
— L mol⁻¹ s⁻¹ (k)
Average Rate Constant & Final Rate Law
—
Average k (L mol⁻¹ s⁻¹)