# Posts by amper

Total # Posts: 22

chemistry
just take H2O AND CH3CH2OH as example.why say that h2o can form two hydrogen bond per molecule but CH3CH2OH only one.i am confused as both of them also has two lone pairs per molecule,is it true that one hydrogen atom will result in only one hydrogen bond and two hydrogen bond...

Physics
that means move towards or backward the object?

Physics
suppose the camera has only one len .if i want to take a sharp image of a distant object,how should the len move,forward or backward.how about if nearby object?

math
let x be one of the part of the string and represent ratio 3,that mean 40-2x represent ration 2 x/(40-2x)=3/2 x=15 that mean the string can be divide into 15cm, 10cm and 15cm

geometry
a^2+b^2=c^2 a,b & c are sides of a triangle note: a+b>c a+c>b b+c>a

math problem
7(41-5Y) +8Y =44 SOLVE Y AND THEN PUT Y = ? IN X=41-5Y THEN SOLVE X in fact ,purpose of substitution is to make a equation have only one unknown so that we can easily solve the problem

physics
insufficient information,cant ans it

physics
in fact,there are many different affect on the gas particles when heating the gas due to different condition.this is taught in a topic of gas law and kinetic theory.but simply saying,when heating a gas,the average KE OF GAS PARTICLES increase,then the average speed of each ...

chemistry(balance equation)
S + H2SO4 ----> SO2 +H2O

chemistry(balance equation)
thank you very much,your teaching really makes me a good start. then how about balance S +H2SO4 ---> SO2 +H2O ??

chemistry(balance equation)
Thank you DrBob, but i am only a form 4 student in hk,i havent learnt about anything of redox.is there any SUPER SHORT CUT for balance simple and complex equation?in fact i have asked several people,some of them said that take LCM of the atom counts,but i don't know take ...

Algebra
1/6d + 13 = 20 1/6d =20-13 d/6 =7 d = 7*6 d = 42 3/5(s-8)=9 [3(s-8)]/5=9 3(s-8)=9*5 s-8 = 45/3 s =15 +8 s=23 the next one you try it

pennfoster
ans is b. helped is a verb with past tense

maths
FIRST,look for the unit L----Litre leak?L per minute-------L m^-1 that mean L/ L m^-1 =1/ m^-1 =m therefore, ans: 20/(2/3) =30minutes.

geometry
your question is actually unclear.i think your question lack some criterias.for example,which two lines are equal.just take the numbers u give,BA=BC,then 4y+6=6y-3,then its easy to find y

physics
its just a simple ratio problem solution: 100A X A 0.01 THEN THE EQUATION WILL BE 100A/A=X/0.01

chemistry
concentrated H2SO4(l)(18M)contain 98% H2SO4 by mass,how about the 2 %,is it water?

Physics
when temp increase,that mean average KE increase,if state change from solid to liquid or liquid to solid ,potential energy increase For IDEAL GAS,it wont change to any state under HIGH TEMP LOW PRESSURE,so average KE increase but potential energy remains unchange as far as we ...

chemistry
2NH3 + 3Cuo -----> 3Cu + 3H2O +N2

Chemistry Balancing Equations
i have just learnt a little about balancing equation but i hope i can help your coefficient only: question 1 , 4,7 no need to balance 3)2,1,2 6)only HCL had a mole ratio of 2 the other i don't know,sorry

chemistry
aluminium is excess. let x be the maximum mass of AlCl3 (x/133.5)/(35/71)=2/3 x= (find x by yourself)

science
it is a compound.because it exists more than one element and also this two element has change of their no of electrons.that means sodium HAS REACTED with chlorine and changed to a product. OF course,sodium chloride can dissolve in water,and we call this a sodium chloride ...

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