bio+ chem 問題..

小霞的fans

consider the reflex action when a man touchs a hot pot.There are sensory neurone , interneurone and motor neurone over the pathway.There is another neurone'X' which transmit the nerve impulses to the cerebrum.

which neurone is consider to be damaged ( include neurone'X') when

a)the man withdrawl his hands but do not feel any pain
b)the man feel the pain but do not withdrawl his hand
c)the man do not withdrawl his hand and do not feel any pain

我唔明a  . .你都feel唔到pain 又點會縮手呀 -00-"
唔明點解a果條係neurone"X"
完全唔明點解c果條係sensory neurone..
只要sensory neurone 一damaged,,就乜都冇!? 佢唔係只會feel 唔到pain架咋咩!?

=====================分隔線============================

2 equal masses of magnesium (excess) is mixed with dilute hydrochloric acid with different concentration.
我唔明點解high cocentration 果個會放多D hydrogen ,, 唔係話就算dilute左mole數都一樣架咩..唔係話high concentration only speeds up the reaction咩!?咁low concentration 果個應該都會放同樣數量既hydrogen架!? 只係用既時間長D姐。點解high cocentration 果個會放多D hydrogen ><? THX!

Ivanhy92

Biology:

a)
我唔明a  . .你都feel唔到pain 又點會縮手呀 -00-"

>>

就算feel唔到都一定會縮手,因為縮手動作係經 Sensory->Interneurone->Motor

feel唔到痛可能係 => Sensory / X 有事

Withdrawl reflex你覺得痛係因為個nerve impulse又會行第2條route: Sensory -> X ->...-> CEREBRUM -> ... -> Motor
(只不過第1條route快過第2條route)

Can withdraw his hand => Sensory一定冇事(第1條route必經) Motor一定冇事

So, X is damaged


c)
do not withdrawl his hand => Sensory / Interneurone / Motor有事

do not feel any pain => Sensory / X / Cerebrum有事

只要sensory neurone 一damaged,,就乜都冇!? 佢唔係只會feel 唔到pain架咋咩!?
>> 只有Sensory會一定首先經哂2條route,題目話只有一種neurone damaged, 所以係sensory

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Chem:

2 equal masses of magnesium (excess) is mixed with dilute hydrochloric acid with different concentration.
我唔明點解high cocentration 果個會放多D hydrogen ,, 唔係話就算dilute左mole數都一樣架咩..

>> 唔夠資料, 冇話 dil. HCl係咪Same volume...

No. of mole =  Volume (dm^3)/ Molarity (mol dm^-3)

唔知Volume係幾多, No. of mole就一定冇結論...

樓主千萬不要死記 Conc. 同 Dil. Mole number一定一樣,要睇清楚Question有冇俾足夠資料,3個資料缺乏左2個就冇結論

所以:

咁low concentration 果個應該都會放同樣數量既hydrogen架!?

>>係唔可以肯定是否放出一樣多既Hydorgen.

希望能回答到樓主既疑難.

Royal

講講BIO題
我建議樓主好好REVISE返...係最基本既清CONCEPT題黎
基本上有兩條path
stimulus-->sensory neurone-->interneurone-->motor neurone-->reflex action
                                              |(X)
                                              |-->brain --> 再作出voluntary action/感覺

換句話說, 要有reflex action(i.e. withdrawal), sensory, interneurone及motor neurone必須齊全
而要有感覺或者voluntary action, 則sensory neurone, interneurone一直去到brain都要正常

小霞的fans

Biology:

a)
我唔明a  . .你都feel唔到pain 又點會縮手呀 -00-"

>>

就算feel唔到都一定會縮手,因為縮手動作係經 Sensory->Interneurone->Motor

feel唔到痛可能係 => Sensory / X 有事

Withdrawl ref ...
arararchchch 發表於 10/9/2009 12:19 AM

                               
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喔喔原來係咁. . 唔該+)CHEM 果題我打少左- - "
果2個ACID　係SAME VOLUME -00- SORRY..
亦都謝謝ROYAL +)

simon199392

首先, No. of mole =  Volume (dm^3)*Molarity (mol dm^-3)

因為volume係constant, 當M愈大, 乘出黎個No. of mole就愈大.
換而之, H+ ion ge mole就大左,

ie. mole ratio by formula eg. HCl : H+
                                      (^)  (^)

既然多左H+用, 放出ge H2就愈多
ie. 2H+ + 2e- --> H2
     (^)              (^)

**(^)=increase

小霞的fans

首先, No. of mole =  Volume (dm^3)* Molarity (mol dm^-3)

因為volume係constant, 當M愈大, 乘出黎個No. of mole就愈大.
換而之, H+ ion ge mole就大左,

ie. mole ratio by formula eg. HCl : H+
        ...
simon199392 發表於 10/9/2009 11:46 PM

                               
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咁書上面寫果個dilute左mole數不變即係點><...
dilute左molarity decreases,,咁mole數都應該decrease架><...

simon199392

咁書上面寫果個dilute左mole數不變即係點>
小霞的fans 發表於 12/9/2009 12:16 PM

                               
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dilute左mole數不變, 係因為當M下降果陣, 你個volume將佢倍番大(加水).
所欲一樣野做左dilution之後mole數是不變,
但你要知道他們的volume係唔同ge,
dilute的volume大過concentrate的volume,
正因為咁先有M1V1=M2V2的formula,
其實姐係no. of moles before dilution=no. of moles after dilution

而你題目given係same voume, 所以...嗯...就這樣