Search results

Yes, in a way. You can weigh the pieces of iron before the experiment, then try all the different conditions for the same amount of time. Then when it's over, you can clean the rust of the bits of iron and re-weigh them. The more mass it has lost, the faster the corrosion has been.

What suburb? I am a teacher and HSC marker.

It's a lot better than ethanol. Don't worry. At least in this elective it's about facts not about what might happen in the future, and there is some chemistry in it even!

Until about a year ago, molar volumes were quoted at 101.3 kPa ( 1 atmosphere) and either 0 or 25 deg celsius. Apparently for years, the standard pressure has been changed to 1 bar which is 100 kPa. The Board of Studies has decided to go with this and since the pressure isa bit lower, the...

The O2 concentration actually increases with a drop in temperature. However little O2 is available due to (a) lack of contact with the atmosphere (b) lack of photosynthesis and (c) consumption by respiration. The temperature and O2 stories should be treated separately.

Well for starters people who get 90% would know that there is no apostrophe in gets when it is a verb.

Contexts is the best text in my opinion, then Conquering Chem. Pathways is good in bits but inferior to the other two. You definitely don't have to learn solubility rules. Don't waste your valuable time. :)

Is the security period for this exam over??? I don't think so.

There is a security period on both the Catholic and Independent Trials. Any school found to be breaching these ( i.e. by discussing questions on this forum) can really get into trouble. My recommendation- wait. ;)

Learning the activity series is so 1960's. The table of standard electrode potentials is close enough. I wouldn't lose any sleep over this one. :o

Correction: the stock solution is 0.424g/L ( 0.106/0. 25) which is 424ppm as 1 ppm is very close to 1 mg/L.

You poor person. The first problem comes from Conquering Chemistry p 222 and is harder than any HSC question, but good practice. For the calibration curve you have to work out the concentration of the stock solution in ppm. You divide 0.106 by 250 mL and get 0.424 g.mL or 424ppm. Now you have...

Ok your chem teacher may have been drinking one of his/her concoctions because H-bonding explains everything here. Alkanes have only dispersion forces as their intermolecular forces as they are more or less non-polar. Alkanols have an -OH group so they have not only dispersion forces but also...

A passivating metal is one which reacts with the atmosphere, usually oxygen, to form a surface layer which is impermeable and therefore prevents further reaction e.g. aluminium, zinc. An active metal like iron on the other hand reacts with oxygen and water but the surface layer is porous so...

Also because catalysts are used in the Haber process, it is important that no chemicals which "poison" the catalyst enter the reaction chamber.

The vanadium lady is Professor Maria Skyllas-Kazakos at UNSW.

I think that if you add the zinc nitrate solution to the lime water ( calcium hydroxide solution) you will get a precipitate of zinc hydroxide. This won't happen with the barium chloride as barium hydroxide is soluble. So if you combine Xayma's tests with mine you get them all identified.

Be careful with covalent bonds. Sure they hold the atoms together in molecules such as H2O, CO2 etc, but they also hold the network together in diamond, SiO2, SiC and within the layers of graphite.

tinned beetroot contains vinegar so that's putting in extra acid. Fresh beetroot is the go. Red cabbage is even better, and I believe tea works as well. Then there's flowers- any dark purple flower works well, e.g. morning glory, tibouchina etc etc;) :)