Qualification > Reference Material

Chemistry P6 18/5/010

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WARRIOR:

--- Quote from: red_911 on May 17, 2010, 08:54:42 pm ---hey plzz tell if sodium hydroxide reacts with magnesium ? reason also...

--- End quote ---

metals dont react with alkalis..

WARRIOR:

--- Quote from: Shooting Star on May 17, 2010, 09:00:30 pm ---you said it varies but how do you know which to choose
ok an example...p6 2009 O/N q6a

--- End quote ---

in this case.. it is lower temperature. so the reaction is slower .

therefore.. you have to draw the line above the plotted line ? why?

well it has to be slower so..if u draw it above and check a point for example at 1 minutes..the mass decreases by less amount


but if u draw it below adn check a point ..the mass will decrease by more amount..understand?

$H00t!N& $t@r:

--- Quote from: Kimo Jesus on May 17, 2010, 09:04:39 pm ---in this case.. it is lower temperature. so the reaction is slower .

therefore.. you have to draw the line above the plotted line ? why?

well it has to be slower so..if u draw it above and check a point for example at 1 minutes..the mass decreases by less amount


but if u draw it below adn check a point ..the mass will decrease by more amount..understand?

--- End quote ---
i dont understand how??? how can you tell diff in mass. do you plot points when drawing the secod curve or do you draw another curve below the first curve anyhow, with no particular order?

WARRIOR:
look

just draw another curve the same way that the first one is draw

  ---------------------------------
                                                l
                                                l
                                                l
                                                l
                                                l
                                      this is 1 minute..

now do that and  the first curve shows 178 grams

if u do the same thing wiht the seconde curve which u draw above the first

it will be more than 178 grams ..it can be anywher above ..just shows wht happens whn teh temp is lower

Ghost Of Highbury:

--- Quote from: Shooting Star on May 17, 2010, 09:22:01 pm ---i dont understand how??? how can you tell diff in mass. do you plot points when drawing the secod curve or do you draw another curve below the first curve anyhow, with no particular order?

--- End quote ---

Just roughly draw the curve above the previous curve. This is because as the temp. is lower , the reaction is slower meaning HCl and CaCO3 will react slower. Thus, the mass of the contents will decrease slowly.

For e.g At, a specific time the mass of the contents will be higher than that in the previous curve.

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