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you mean u wanna know how a divided flask looks like ?Can you please draw it for me?
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you mean u wanna know how a divided flask looks like ?Can you please draw it for me?
Yupyou mean u wanna know how a divided flask looks like ?
can u see that? u connect it to a gas syringe and once u remove the barrier between them the reaction will start and that way u will have no loss of oxygen because the syringe will be already connected
Oh it does makes sense, Saw labelling it will just be ' a barrier to initial separate the H2O2 from the catalyst' right?can u see that? u connect it to a gas syringe and once u remove the barrier between them the reaction will start and that way u will have no loss of oxygen because the syringe will be already connected
yeah u can say that!Oh it does makes sense, Saw labelling it will just be ' a barrier to initial separate the H2O2 from the catalyst' right?
Thanks a lot bro.
Ashique . its probably too late now...but the moles you calculated in the 2nd bullet point should be 0.001 mol, giving a mass of 0.25g in 100cm^3 water.@kazi umayer alim
In this experiment we get a precipitate. The prediction that we're putting into test is that the moles of of the precipitated copper hydroxide increases with the increasing conc. of CuSO4.
Thats about it! Hope it helped!
- So keeping our hypothesis in our mind, we should know that the conc. of CuSO4 is the independent variable, which means it is in our control. Hence, you need to prepare a range of concentrations of CuSO4. You're also aware of the fact that the solutions saturates at 1.39 mol/dm3. So the range of concentrations that you prepare must not exceed 1.39 mol/dm^3. So your range is going to be 0-1.39 mol/dm^3. You need to prepare at least five diluted solutions.
- Say you're going to prepare 100 cm^3 of each of the following conc. range: 0.01, 0.05, 1.00 1.10, 1.20 and 1.39. You need to tell the examiners exactly how you're going to prepare them. Since you're given SOLID hydrated CuSO4, you're going to have to dissolve a certain mass in water. So say you want to make the 0.01 mol/dm^3 solution- you need to know how many moles are are to dissolved in a 100 cm^3 solution. So Moles= CV= 0.01*100*10^-3= 0.01 mol. So you need to dissolve 0.01 mol of hydrated CuSo4 in 100 cm^3 of water. To find out the mass= Moles*Mr= 0.01*249.6= 2.50 g. So you dissolve 2.50 g of the salt into 100 cm^3 of water to make a 0.01 mol/dm^3 solution. The rest of the concentrations are to be prepared in the same way- but you don't need to show the working. One calculation for conc. should be enough.
- After you've added the NaOH into the solution a precipitation of Cu(OH)2 will occur. You need to filter this (Or centrifuge it,and then decant).You could leave it out to dry, or add water and propanone.
Thanks Mateyeah u can say that!
what is a spindle? i searched but still no clueMeasuring enthalpy change of combustion!!
Take an empty spindle weigh it and then pour any alcohol and re weigh it
setup a dry wrick and cap the spindle to avoid evaporation ofuel
take 150 cm3 metal can pour 50 cm3 water and place it over spindle on a table alike
measure the initial temp of water
light the spindle and keep measuring temperature until their is a rise of 10*C
recap spindle allow it to cool remove cap and wrick and reweigh it
substract mass after heating and before heating u'll get the mass which is burnt in excess oxygen
use q=mc4T and u'll get enthalpy change of combustion
you can use a spirit lamp contaning the fuel .....refer to m-j 2008 ....there a useful diagram in the question itselfwhat is a spindle? i searched but still no clue
The mass of water: C-Bcan some1 just quickly exaplain M-J 2011 v.53 ...question 2 ...about solubility in g/100g of water ....how do we exactly solve for that colomn ....pls reply soon
mass of solid/mass of water x 100Asalamualikum i just wanted to ask whats the actual formula to find solubilty because i am really confused some say its is mass of solid divided by100 g of water but others say its mass of solid by mass of water into 100 can u plz tell me whats the correct formula ?jazakAllah
wat bout the 100 g of water ...plz elaborate on that ....if solubility is supposed to be mass of solid over 100 g of water ...the volume of water calculatedfrom the coloumn would not give 100g !?!!The mass of water: C-B
Mass of solid dissolved: D-C
Solubility: (Mass of solid x 100) / mass of water.
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