investigating chemical Equilibrium

Questions A molarity increase from. 1M to 0. 2M of NaOH would result in fewer drops required to produce a colour change. The OH- particles are more concentrated, requiring less shifting as it speeds up. The stress of NaOH converts the hydroxide into the final product, which reacts with the iron (III). As concentration decreases, the reaction shifts leftward. It forms a new equilibrium where the iron is lower than before the stress, and the colour changes from red to yellow. When hydrated cobalt (II) is refrigerated, the temperature decreases; it would be an endothermic reaction since the equilibrium will shift to the left as the temperature decreases, favouring the reactants and causing the colour to turn light pink. In this reaction, the energy is on the reactant side, which leads to an endothermic reaction whereby the colour changes from pink to dark purple as more heat is added. Increasing temperature increases the rate at which a reaction proceeds, as explained by Chatelier's principle. The concentration of chloride ions would increase by adding sodium chloride. The concentration was higher than the original equilibrium and caused the liquid to turn purple by forming sodium; the equilibrium shifted to the left, allowing the chloride ions to be removed. Forward and reverse reactions would increase with time; as forward reactions increased, the chloride ions would be used up, causing stress and shifting the equilibrium to the right. Cr2O72- + 2OH- <--> 2CrO4 + H2O By adding NaOH, sodium ions and hydroxide ions dissociate, and hydrogen ions combine with hydroxide ions to form water. The hydrogen ion decreases in concentration, shifting the reaction to the left and turning into a yellow colour, like in the beginning. In step three, HCl is added and dissociates into hydrogen and chloride ions, causing the hydrogen to increase and shift the reaction to the right. In step four, the HCl increases hydrogen concentration, shifting it to the right, causing it to turn orange. When adding back the NaOH, it decreases and shifts to the left as it turns back into the original yellow due to more chromate. Barium dichromate is more soluble than barium chromate since barium dichromate is more visible and apparent light orange colour, as the chromate is cloudy and not as visible. In step seven, HCl and barium were added, causing a shift to the right, making more dichromate, meaning there was more concentration solution left and no precipitation left. In step 9, there was a lower concentration meaning barium nitrate could form a precipitate. Follow-Up Questions: smtg about SCN After realizing the test tube in part seven does not contain precipitate, the student should clean the test tube with HCl to remove any leftover precipitate from part IV.