A forensic chemist is given a white powder by the investigator of a crime scene. The investigator wants to know if the powder is a pure substance or a mixture. The chemist dissolves some of the powder in deionized water making a clear solution. She finds that a precipitate forms when she adds an excess aqueous solution of sodium chloride. She filters the precipitate and washes it several times with deionized water. To this filtrate she then adds an aqueous solution of sodium carbonate. A precipitate forms. Question: Draw two pictures representing a molecular / atomic / ionic view of what occurred when a precipitate formed with the addition of sodium chloride solution. Choose the type of particle that is the most appropriate for this reaction. Place charges on any ions indicating charge values (+1, -2, etc.) when they are known. If charges are unknown indicate whether the ion is positive or negative. Clearly indicate which picture represents before the reaction occurs. Should include: 1. Five different ions must be shown: 3 cations and 2 anions. The number of ions is not important. If specific charges are shown, the net charge must be zero: 2. Two different cations and one anion must remain as spectators (unreacted) 3. The charges of +1 and -1 must be shown before the reaction since these represent the sodium and chloride ions whose charges are known 4. The charges on the precipitate must add to zero. That is, if the charge of the reactive cation is +2, then this must combine with two -1 chloride ions:
A
Question: Draw two pictures representing a molecular / atomic / ionic view of what occurred when a precipitate formed with the addition of sodium chloride solution. Choose the type of particle that is the most appropriate for this reaction. Place charges on any ions indicating charge values (+1, -2, etc.) when they are known. If charges are unknown indicate whether the ion is positive or negative. Clearly indicate which picture represents before the reaction occurs.
Should include:
1. Five different ions must be shown: 3 cations and 2 anions. The number of ions is not important. If specific charges are shown, the net charge must be zero:
2. Two different cations and one anion must remain as spectators (unreacted)
3. The charges of +1 and -1 must be shown before the reaction since these represent the sodium and chloride ions whose charges are known
4. The charges on the precipitate must add to zero. That is, if the charge of the reactive cation is +2, then this must combine with two -1 chloride ions:
Trending now
This is a popular solution!
Step by step
Solved in 3 steps with 3 images
