Identification of a Compound by Mass Relationships - Lab Report Example

The solid formed will be heated with hydrochloric acid and then identification of the compound based on the Q-value.Q- theoretical value is based on a stoichiometry calculation similar to those done in class while the experimental value of Q is gotten from the experiment. Both unknowns end up as a chloride salt at the end of the experiment. Depending on the unknown present, there are two possible chemical reactions that will be performed in the lab:If the unknown is NaHCO3, then the overall reaction in the experiment is:NaHCO3(s) + HCl (aq) NaCl (aq) + CO2 (g) + H2O (l) If the unknown is KHCO3, then the overall reaction in the experiment is:KHCO3(s) + HCl (aq) KCl (aq) + CO2 (g) + H2O (l) The value of Q obtained in the lab is calculated using the formula:Q= mass of original unknown- a mass of final chloride/ mass of original unknown.

Chemicals and equipmentCrucible and Cover Ring StandIron RingClay Triangle Bunsen burnerProcedureA crucible was cleaned and rinsed well with distilled water then heated to dry it completely before obtaining its mass. The mass of the empty crucible was recorded.0.5 g of the unknown was transferred into the crucible then the crucible with the unknown weighed and its mass recorded.The crucible and its contents were placed on the clay triangle and heated for about ten minutes then cooled for another ten minutes and its mass obtained and recorded.

30 drops of hydrochloric acid were slowly added to the sample, one drop at a time allowing effervescence to take place.This mixture was then placed on the clay triangle and heated gently for about ten minutes to evaporate water and the excess HCLLastly, it was heated till the bottom of the crucible was red hot then cooled and the mass of the crucible and its solid weighed and recorded.ResultsMass of crucible+ cover = 26.699gMass of crucible+ cover+ unknown = 27.199gMass of unknown = 0.5gMass of crucible + solid chloride = 27.

029gMass of solid chloride = 0.33g.CalculationsFrom the equation: NaHCO3(s) + HCl (aq)