By: James Stewart
To calculate mole ratios
There are two types of chemical analysis; qualitative analysis which is the identification of a substance present in a material, and qualitative analysis which measures the amount of the substance. In this lab, you will perform a quantitative analysis of a two-step reaction. Copper(II) oxide will be synthesized from a known mass of copper(II) sulfate pentahydrate. Using the relationship of the balanced equation, and other stoichiometry relationships, you will calculate a theoretical yield of CuO, and your actual yield. You then will calculate a percent yield.
Copper(II) sulfate pentahydrate will be dissolved in water and reacted using a double replacement reaction with sodium hydroxide. The addition of hydroxide ions to a solution containing copper(II) ions results in the precipitation of copper(II) hydroxide.
Subsequent heating of the copper(II) hydroxide results in decomposition to copper(II) oxide and water.
The CuO can be quantitatively filtered, dried and weighed. The overall reaction for the sequence is:
You will perform the reaction with an accurately weighed amount of CuSO45H2O. From this amount, you will calculate the amount of copper(II) oxide that should be formed (theoretical yield). By performing the experiment, the experimental yield is obtained and this value is compared with the theoretical yield. The ratio of the experimental to the theoretical (times 100%) is the percent yield.
Safety goggles 100-ml beaker
Ring stand Watch glass
Small iron ring Balance
Large iron ring with wire gauze Weighing dish
Bunsen burner Drying oven or light
Beaker tongs 10-ml graduated cylinder
Filtering funnel Rinse bottle with deionized water
Whatman #1 filter paper 1.8 to 2.2 grams CuSO45H2O
250-ml beaker *10 ml of 6.0 M NaOH solution
* For 100 ml of a 6.0 Molar solution of NaOH, Using a 100-ml volumetric flask, dissolve