Page 2 of 3
Re: Can't Judge A Powder B
Posted: November 17th, 2022, 4:47 am
by drcubbin
Chemical-Reactions wrote: ↑November 5th, 2022, 2:34 pm
How do the types of ions affect a solution's conductivity? - Travis Y
When dissolving a solute into solution you create "dissociated" ions, meaning they are no longer "associated" with other ions. For example, when you put NaCl into water the solid "dissociates" and "ionizes" (creates ions) into Na+ and Cl- ions. These are dissociated ions. The "type" of ions are not as important as the VOLUME of ions. So the MORE ions you have (by dissolving more salt into the water), the more ionization takes place. The more ions present, the greater the conductivity.
Re: Can't Judge A Powder B
Posted: November 17th, 2022, 4:48 am
by drcubbin
drcubbin wrote: ↑November 17th, 2022, 4:38 am
knightmoves wrote: ↑November 7th, 2022, 6:23 pm
EllaYu wrote: ↑November 4th, 2022, 11:32 am
For this event how much powder will be given?
That's up to the event supervisor. Each team will be provided with the same quantity of the powder, and you can reasonably assume an adequate quantity to conduct multiple tests, but it would make sense to plan on being economical with the powder you are given.
EllaYu wrote: ↑November 4th, 2022, 11:32 am
Will hot water be given during the event too?
Read rule 2d and 2e. You are guaranteed to get NaOH, HCl, and distilled water (room temp!) in a wash bottle. You may get almost anything else the ES decides to give you, which might include a hot plate, or hot water, or might not.
Yes, be as "economical" as possible! When running this event, we often see students who have not practiced the hands-on parts chemistry events using the materials as if they are baking a cake! I always make a point of letting teams know that powders and liquids will NOT be replenished, but we still get a few who think this is baking class and use too much - especially powder.
Re: Can't Judge A Powder B
Posted: November 17th, 2022, 6:06 am
by B4Queen
So I have all the materials to make a 9-volt conductor but how do I use it? Information would be appreciated!
Re: Can't Judge A Powder B
Posted: November 21st, 2022, 12:27 pm
by B4Queen
Once I build the conductor how do I use it to test the conductivity of a substance?
Re: Can't Judge A Powder B
Posted: December 12th, 2022, 6:39 pm
by randomdogonapc
I’m probably asking a pretty basic question, but could anyone point me to a list of typical observations that are important? For example, a list with all of the typical questions? I just want to prepare myself with the most typical things memorized before I dive into the less obvious properties. Lot of typicals lol
Re: Can't Judge A Powder B
Posted: December 24th, 2022, 7:30 am
by drcubbin
Chemical-Reactions wrote: ↑November 5th, 2022, 2:34 pm
How do the types of ions affect a solution's conductivity? - Travis Y
Generally speaking...
> concentration of ions = >conductivity
> size of ion size --> decreased pair formation --> greater ion strength --> greater conductivity
Re: Can't Judge A Powder B
Posted: December 24th, 2022, 7:42 am
by drcubbin
randomdogonapc wrote: ↑December 12th, 2022, 6:39 pm
I’m probably asking a pretty basic question, but could anyone point me to a list of typical observations that are important? For example, a list with all of the typical questions? I just want to prepare myself with the most typical things memorized before I dive into the less obvious properties. Lot of typicals lol
The best way to become a master of this skill (like any other) is to do A LOT of experiments with your partner and OBSERVE!!
- color changes (turns blue, red, clear...)
- temperature change
- increase bubbling
- goes into solution (dissolves) and be specific: fully, quickly, partially, etc...
to name a few!
Re: Can't Judge A Powder B
Posted: December 24th, 2022, 7:55 am
by drcubbin
g-gills wrote: ↑November 16th, 2022, 12:47 pm
How could the size of individual particles be measured?
Why would you need to know this?
Re: Can't Judge A Powder B
Posted: January 6th, 2023, 3:00 pm
by Peiyinglovesscience
What is a Benedict’s test+how do you preform the test?
Re: Can't Judge A Powder B
Posted: January 7th, 2023, 8:52 pm
by knightmoves