welcome UltimaOnline!
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welcome to homework forum!
we will have UltimaOnline as a new mod!
*clap clap*
hope you will enjoy ur stay and have fun here!
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Thank you for the warm welcome, hiphop2009, owner of the SgForum's Homework Forum! Your Homework Forum has helped many a grateful Sg student preparing for the exams.
I'll take this opportunity as Mod to share the joy of Chemistry. It is my hope that more students at the secondary school levels and 'O' levels will enjoy Chemistry enough to opt to take it up at the 'A' levels, in the Polytechnics, or beyond that in the Universities.
The following is one of my favourite classic questions that I personally designed and wrote, to challenge my students and to illustrate how Chemistry is really lots of fun :
A bubble of gas (initial diameter 1.585 cm; mass 2.0973 x 10^-2 g) that contains twice as much oxygen as it does carbon dioxide, emerges from a photosynthesizing aquatic plant (there’s a plesiosaur reptile aka “Loch Ness monster” right next to the plant, btw) at the bottom of a lake, where the temperature is really cold and the pressure is 6.4 times greater than at the lake’s surface; and the bubble rises until it reaches the surface of the lake (which happens to be at sea level, and at that moment is equivalent to room temperature), and bursts “pop!”.
i) Calculate the diameter (in cm) of the bubble just before it bursts.
ii) Calculate the body temperature (in °C) of the plesiosaur at the time the bubble emerges.
iii) Calculate the diameter (in cm) of this gas bubble if it were instantaneously teleported to the core of the sun (600 thousand times hotter than room temperature and 340,000 million times more crushing than Earth’s sea level atmospheric pressure), and assuming it somehow remains miraculously intact (although in reality, you probably wouldn't want to be hanging around an environment so hot and crushing that atomic nuclei are constantly and forcibly being fused together).After attempting the above, check your Answers :
(i) 3.0 cm.
(ii) 8 deg C.
(iii) 0.0159 cm.
Everyone Loves Chemistry! -
Also, here is a classic Redox-&-Stoichiometry-&-Annoying question that I always tormen... I mean, nuture, my students (both 'O' and 'A' levels) with :
The answers are :
(a)(i,ii,iii) Always remember that hydrogen peroxide can be either oxidized (to oxygen gas) or reduced (to water), and thus quickly balance these half-equations yourself, instead of wasting time referring to Data Booklet.
(a)(iv) 3.375 x 10^-3 mol
(a)(v) 46%
(b) +2
Everyone Loves Chemistry! -
now we got 三大科å¦å¤©çŽ‹ in homework forum!
eagle- physics pro
ultimateonline- Chemistry pro
darkie- Biology pro
.......
....and of course not forgetting tamago...Maths pro!
thankyou!
sincerely from hiphop2009, owner of homework forum~
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Welcome!!! =D
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Thank you, Darkness_hacker99 (and eagle too), for your recommendation of Moderatorship to hiphop2009.