AP Chemistry P2 Experiment 2: Formula of a Hydrate 9/24/2013 Purpose: Calculate the percent composition of water in a hydrate and determine the empirical formula of the hydrate. Procedure: 1) Set up ring stand with ring clamp, clay triangle, crucible with lid, and burner. Adjust the height of the ring stand. 2) Dehydrating Procedures: 3. Measure approximately 1 g of Copper(II) Sulfate Hydrate into the crucible and crucible and lid.
This solution was placed in a burette and 18.4 cm3 was required to neutralise 25 cm3 of 0.1 moldm-3 NaOH. Deduce the molecular formula of the acid and hence the value of n. 5. Sodium carbonate exists in hydrated form, Na2CO3.xH2O, in the solid state. 3.5 g of a sodium carbonate sample was dissolved in water and the volume made up to 250 cm3. 25.0 cm3 of this solution was titrated against 0.1 moldm-3 HCl and 24.5 cm3 of the acid were required.
While the water is heating, remove the foil from Erlenmeyer flask and place about 2 mL of unknown liquid in the flask; then replace the foil and rubber band. 6. After the water has been brought to a boil, record its temperature. 7. Insert the Erlenmeyer flask into the boiling water.
Next, take out the filter paper and add 50 mL of water. Pour the solution into the vacuum flask and decant evenly into two beakers. Add 1 mL of 0.1 M potassium phosphate into the first beaker. It is negative and indicated no excess lead ion in the solution. Add 1 mL of 0.1 M silver nitrate into the second beaker.
The samples don’t have to have the same mass as long as it’s between 0.3 and 0.4g. Add about 20mL of water and 3 drops of phenolphthalein indicator to each sample and allow the solid to dissolve. Prepare a 50mL buret for use by washing it, rinsing it with tap water, and rinsing it twice with distilled water. Finally rinse it twice with 5mL portions of your sodium hydroxide solution. Mount the buret on the ringstand and fill it above the zero mark with the prepared sodium hydroxide solution.
Computer Additivity of Heats of Reaction: Hess’s Law 18 (1) Solid sodium hydroxide dissolves in water to form an aqueous solution of ions. (2) Solid sodium hydroxide reacts with aqueous hydrochloric acid to form water and an aqueous solution of sodium chloride. NaOH(s) + H+(aq) ) + Cl–(aq) → H2O(l) + Na+(aq) + Cl–(aq) ∆H2 = ? OBJECTIVES • • • • In this experiment, you will Combine equations for two reactions to obtain the equation for a third reaction. Use a calorimeter to measure the temperature change in each of three reactions.
Show your work and write a short explanation with each calculation. Part I: Calculate the energy change (q) of the surroundings (water) using the enthalpy equation qwater = m × c × ΔT. We can assume that the specific heat capacity of water is 4.18 J / (g × °C) and the density of water is 1.00 g/mL. The water has absorbed the heat of the metal. So, qwater = qmetal Using the formula qmetal = m × c × ΔT, calculate the specific heat of the metal.
In this experiment, the salicylic acid is insoluble in cold water and can be collected by vacuum filtration. Procedure As the lab, synthesis of salicylic acid, had done, micro-scale was used. To begin, 3.5mL of water was poured into a 10 mL round-bottomed flask. And 0.48 g of sodium hydroxide was added to the flask. After the solid was dissolved, 230mg of methyl salicylate was added using a graduated pipet to the NaOH solution.