Chemical Equilibrium and Le Chatelier’s Principle Lab Study Guide

Experimental Data and Chemical Equilibrium Trials

• Trial 1 Experimental Parameters:     * Volume of $Fe(NO_3)_3$: $5.00\,cm^3$     * Volume of $KSCN$: $1.00\,cm^3$     * Measured Absorbance: $0.693$

• Trial 2 Experimental Parameters:     * Volume of $Fe(NO_3)_3$: $5.00\,cm^3$     * Volume of $KSCN$: $3.00\,cm^3$     * Measured Absorbance: $0.693$

• Trial 3 Experimental Parameters:     * Volume of $Fe(NO_3)_3$: $5.00\,cm^3$     * Volume of $KSCN$: $5.00\,cm^3$     * Measured Absorbance: $0.693$

• Reference Absorbance Data:     * The absorbance at $L_{max}$ is recorded as $2.000000$.

Equilibrium Concentration Calculation Procedures

• Reactant Concentration Calculations:     * The initial concentrations of each reactant must be calculated for every trial.     * The calculation process must explicitly account for the dilution of each reactant when mixed.

• Product Concentration Calculations:     * The equilibrium concentration of the product is derived based on the measured absorbance values provided in the data table.

• RICE Table Integration:     * For every trial (Trial 1, Trial 2, and Trial 3), a RICE (Reaction, Initial, Change, Equilibrium) table must be constructed.     * The table must contain:         * Initial concentrations of all reactants.         * Initial concentrations of all products.         * Equilibrium concentrations of all reactants.         * Equilibrium concentrations of all products.

• Equilibrium Constant Determination:     * The value of the equilibrium constant $K_c$ must be calculated using the data from the RICE table for each specific trial.

Le Chatelier’s Principle: Stress Response and Observations

• Added Stress: $HCl$ (Hydrochloric Acid):     * Shift Observed: No change.     * Reason: No reason provided in the transcript.

• Added Stress: $Fe(NO)_3$ (Iron 3 Nitrate):     * Shift Observed: The system became darker, more red, and exhibited a bright red meniscus.     * Reason: No reason provided in the transcript.

• Added Stress: $KSCN$ (Potassium Thiocyanate):     * Shift Observed: The system turned a dark bronze color.     * Reason: No reason provided in the transcript.

• Added Stress: $AgNO_3$ (Silver Nitrate):     * Shift Observed: The system became lighter and developed a white cloud described as murky and milky.     * Reason: No reason provided in the transcript.

• Added Stress: $Na_3PO_4$ (Sodium Phosphate):     * Shift Observed: The system became lighter (noted as a very slight change).     * Reason: No reason provided in the transcript.

• Added Stress: $Na_2C_2O_4$ (Sodium Oxalate):     * Shift Observed: The system turned light yellow, specifically described as "urine color."     * Reason: No reason provided in the transcript.

• Added Stress: $KNO_3$ (Potassium Nitrate):     * Shift Observed: No change.     * Reason: No reason provided in the transcript.

• Added Stress: $FeCl_3$ (Iron III Chloride):     * Shift Observed: The system became darker and appeared more red/bronze.     * Reason: No reason provided in the transcript.

• Added Stress: $NaF$ (Sodium Fluoride solid):     * Shift Observed: The system became clear and transparent.     * Reason: No reason provided in the transcript.

• Thermal Stress: Ice Bath:     * Shift Observed: No change.     * Reason: No reason provided in the transcript.

• Thermal Stress: Hot Bath:     * Shift Observed: The system became lighter.     * Reason: No reason provided in the transcript.

Post-Experimental Analysis and Statistical Measures

• Averaging $K_c$:     * Once the individual equilibrium constants ($K_c$) for Trial 1, Trial 2, and Trial 3 have been calculated, the average equilibrium constant must be determined.

• Average Deviation:     * The student is required to calculate the average deviation for the set of calculated $K_c$ values to determine experimental precision.

Lab Report Documentation Requirements

• General Formatting:     * The report must include appropriate units and significant figures where needed in all tables and calculations.

• Sectional Requirements:     * Chemical Equation: A complete chemical equation for the system under study must be included.     * Discussion: A narrative section discussing the implications of the results and observations.     * Conclusions: A summary of the findings and whether they support the expected outcome of the experiment.     * References: Citations for any external sources or reference materials used in the preparation of the report.     * Identification: All pages must include the Name and Date of the student.