1 / 9

Precipitate Formation: Formation of Lead (II) Iodide

Precipitate Formation: Formation of Lead (II) Iodide. When mixed, two clear solutions produce a dense yellow precipitate. Purpose. To observe the formation of a precipitate from ionic compounds in an aqueous state. Demonstration. The formation of PbI 2(s) from Pb(NO 3 ) 2 and 2KI solutions.

hollye
Download Presentation

Precipitate Formation: Formation of Lead (II) Iodide

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Precipitate Formation: Formation of Lead (II) Iodide When mixed, two clear solutions produce a dense yellow precipitate

  2. Purpose • To observe the formation of a precipitate from ionic compounds in an aqueous state.

  3. Demonstration • The formation of PbI2(s) from Pb(NO3)2 and 2KI solutions. Pb2- NO3- K+ I- NO3- + K+ PbI2(s)

  4. Concepts • Double Replacement Reactions • Solubility • Precipitates

  5. Occur when the elements in a solution of reacting compounds exchange places, or replace one another. AB + CD  AD + CB For this demonstration: Pb(NO3)2(aq) + 2KI(aq) PbI2(s) + 2KNO3(aq) Double Replacement Reactions

  6. Solubility • Salts are substances composed of ions; many salts are soluble in water • Solubility is the amount of a substance needed to make a saturated solution at a specific temperature. • Solubility of solids and liquids varies widely, for example: 35.7g of NaCl dissolves in 100mL of H2O, but only 0.044g of PbI2 dissolves in 100mL of H2O

  7. Solubility • Solubility is temperature dependent. • For gases, an increase in temperature will decrease the amount of gas that can dissolve • For salts, the amount and rate of dissolving will increase as temperature increases: Amount & Rate of Dissolving of Salt Temperature

  8. Precipitates • A precipitate is an insoluble solid formed when two ionic solutions react. • Pb(NO3)2 andKI are ionic compounds that dissociate into ions as they dissolve in water, but when mixed together, undergo a double replacement reaction to form an insoluble yellow precipitate, PbI2. • Sometimes a downward arrow behind a compound is used to indicate that the compound is insoluble; sometimes the letter “s” in parentheses for “solid” is used: PbI2 (s) or PbI2 * Both mean “precipitate”

  9. Conclusions • Soluble ionic compounds dissociate into water and when allowed to react, may produce an insoluble compound known as a precipitate. • If a precipitate is produced, the reaction that occurs is known as a double replacement reaction.

More Related