Effect of calcium ions on rate of reaction.

Loz17

OK well to reach these you will need to mix CaCl2 with distilled water in a testtube by doing the following;

0 mol add 10cm3 of distilled water
0.2 mol- add 2cm3 of CaCl2 to 8cm3 of distilled water
0.4 mol- add 4cm3 of CaCl2 to 6cm3 of distilled water
0.6 mol- add 6cm3 of CaCl2 to 4cm3 of distilled water
0.8 mol- add 8cm3 of CaCl2 to 2cm3 of distilled water
1 mol- add 10cm3 of CaCl2

Thats all you have to write against the concentratons you are using

Hope thats a help! :smile:

Thanks, but what calculations did you do to get to them? I need to show how i worked them out.

Reply 82

No it won't because to make 0.02 moles you'll need alot more water than that and the CaCl2 is only going to increase the Ca ions concentration in the milk, it won't dilute the concentraion further but I do see where your coming from

To make 0.02 mol youll need 2 parts CaCl2 to 98 parts water so it wont dilute any further or cause anymore problems with the milk

Reply 83

amy_1990

Thanks, but what calculations did you do to get to them? I need to show how i worked them out.

Its along the lines of dilution factors although I don't think that is actually them.

Umm I think the calculatons are basically like saying e.g for 0.2 mols you add 2 parts CaCl2 to 8 parts so the calculations are ratios with a sum of 10 (1 part = 1cm3) if you wanted to make 10cm3 of 0.2 mol CaCl2 and you'd double that to 4:16 if you wanted 20cm2 etc.

Thats the main calculations for it sorry its a little confusing :s-smilie:

Reply 84

GodHelpMePass

daone

thank for your help loz17

i was thinking about it if Chymosin AKA rennin breaks down the milk protein casein to paracasein which THEN combines with calcium to form calcium paracaseinate, which is apparently fleck of curds are made of

then increasing the calcium ions doesn't effect the rennin at all but it would increase the rate at which milk coagulates because the curds are forming faster the web page of the quote is from:

what do you think about what i just said????

i think thats why the rate of coagulation increase as you increase ca ions

Well dnt quote me on this ..

but in a way it could stil have an affect on rennin... because wouldnt it mean the more rennin brken dwn... the more likely it is to combine with the calcium henceee the less substrate rennin would have 2 work with.... i cnt xplain it bt hpefully u gt ma jist... i might b hedin in the wrond direction tho.

Reply 85

ar ok, thanks, im sort of understand now!! Im sure itll become clear when i actually put then into the tables!! Thanks for your help! I have jsut got to do that bit now! All good.

Reply 86

daone

GodHelpMePass

nope because the calcium doesn't react with the substrate it react with the product which wouldn't effect the rennin at all but does increase the rate of coagulation because it helps in forming the curd which is coagulation

Reply 87

i thought we don't have to add the distilled water in this experiment..?

Reply 88

vyfly

i thought we don't have to add the distilled water in this experiment..?

how else are you going to make the different concentrations of the ca ions? as we are only given the 1moldm^3, so were going to have to make the others somehow! How were you going to make the concentrations?

Reply 89

i just have different volume of calcium chloride, such as 0.0cm3, 0.5cm3, 1.0cm3....

Reply 90

vyfly

i just have different volume of calcium chloride, such as 0.0cm3, 0.5cm3, 1.0cm3....

the task says, how does a change in coagulation affect the rate of coagulation, surely changing the amount of ca ions, isnt going to make that much difference. concentration is measured in moldm^3, so surely changing the amounts isnt the same, if you understand what i am saying.

Reply 91

The concentrations will be exactly the same in eachof the volumes so you'll have 1 mol of CaCl2 throughout the experiment instead of a range of concentrations. Read up the posts andf find some posts helping you with this they're up there ^^^

Reply 92

Loz17

Have i got it wrong then? You do have to change the concentration, dont you?

Reply 93

but if i put milk, rennin and sodium citrate in constant,, and just calcium chloride in variable,,, does it help for concentration??

Reply 94

vyfly

but if i put milk, rennin and sodium citrate in constant,, and just calcium chloride in variable,,, does it help for concentration??

the concentration of the ca ions need to be changed, well i think they do with the way that i have interpreted th question! You are going to have to have the same amount of milk, rennin and citrate or else the results you get, would be able to be compared!

Reply 95

You do have to have a range of concentrations of CaCl2, amy_1990 you had it right earleir, vyfly you need to read this...

Loz17

Reply 96

so it would be fine if i not add any distilled water?

Reply 97