Hello Professors!
Please see the PDF (SU24 Week 5 Newsletter)for this week’s Digest also found bellow as images.
or scan the QR Code:
Today is Friday, May 31st,
…And these are the trendies demonstrations for the upcoming week!
We are currently re-organizing our lab and the chemicals are just as confused of their location as we are … so while they are still (somewhere) on our shelves, order while you can!
Use the link (Password: hydrogen) to order as well as the full list of demos; as always, early orders are very appreciated!
General Chemistry I
Weekly topics
- Electronic Structure of Atoms
- Periodic Properties of the Elements
- Basic Concepts of Chemical Bonding
Electronic Structure of Atoms
Gas Discharge Tubes of the Noble Gases – show that different gases give different colors when subjected to an electric discharge (H2 tube also available).
Atomic Spectra: Flame Tests – Introduce various metal salts (e.g. NaCl, SrCl2, CuCl2) into an open flame to produce brilliant colors associated with exciting metal cations.
Fireworks Balloons – Show the brilliant colors of metal cations in a fun way by igniting hydrogen balloons containing metal salts.
Periodic Properties of the Elements
Acidic and Basic Oxides – Dissolve several oxides (CaO, ZnO, CO2, P4O10) in water containing universal indicator to show a range of basic and acidic oxides.
Periodic Properties – Add pieces of Li, Na, K, Mg, and Ca, to beakers of water and phenolphthalein to observe the reactivity of metals from different parts of the periodic table. If desired, you can add HCl to those beakers where no reaction occurred.
Basic Concepts of Chemical Bonding
Contrast models of NH2—NH2, NH=NH, and N≡N to show the decreasing N–N bond length as the bond order increases
Show orbital overlap models of ethane, ethene, and ethyne (acetylene).
General Chemistry II
Weekly topics
- Additional Aspects of Aqueous Equilibria.
- Chemical Thermodynamics
Additional Aspects of Aqueous Equilibria
Buffer Capacity Demo – Contrast the buffer capacity of water, 1 M CH3COOH/NaCH3COO, and 0.1 M CH3COOH/NaCH3COO by adding increments of 6 M HCl to each in the presence of an indicator.
Common Ion Effect Demos –HCl/NaCl – add concentrated HCl (aq) to saturated NaCl(aq) to cause precipitation of NaCl (s).
Complex Ion Formation Ni or Cu – Show color change associated with formation of complex ions. In a tall graduated cylinder of Cu2+ or Ni2+ aqueous solutions, carefully add 6 M NH3 to create a layering effect of [M(H2O)62+ / M(OH)2 / [M(NH3)42+]
-CuSO4Â gives a blue / white / dark blue layering
-Ni(NO3)2Â gives a green / white / dark blue layering
Amphoteric Hydroxides: Al3+ and Fe3+ – add NaOH to samples of Al(NO3)3 and Fe(NO3)3 to form insoluble metal hydroxides, then add HNO3 and more NaOH to different samples of each to identify which metal hydroxides are amphoteric.
Chemical Thermodynamics
Money to Burn – Soak a dollar bill in a water-alcohol mixture and then light it with a match; the high specific heat of water keeps the combustion temperature low enough to prevent burning the bill.
An Endothermic Reaction – Shake solid Ba(OH)2 8 H2O with solid NH4NO3 to produce an aqueous mixture of Ba(NO3)2 (s) and NH3 (aq). The reaction is endothermic enough to freeze the flask to a wet piece of cardboard. Alternatively, a digital thermometer can be used to record the temperature change.
Have a great week!
P.S. If you are ahead/behind of schedule, let us know so we can adjust the demos accordingly. Currently we are simply using the syllabi to guess where your respective classes are at. And here is the link again
Hello Professors!