Edexcel CHEMISTRY DOUBTS!!!!

[Alaa Mounier]

can anyone solve this question?
A- Aluminum is extracted by electrolysis of Al2O3. What is the maximum mass of the metal that could be obtained from 1 tonne of the oxide?
B- If the yield of the electrolysis plant is 90%. What mass of the oxide must be used to produce 1 tonne of aluminum? 

[conquerpro]

can anyone please solve this question?i need it ASAP.when excess calcium is added to water what is observed?

[Candiah]

When Calcium is added to water it fizzes (efferevescence); water turns milky or cloudy. Calcium hydroxide is not very soluble in water.
Ca + 2H20 -----> ca(OH)2  + H2

[conquerpro]

what is the oxidation state of ozone O3?

[Candiah]

Io3-  + 5 I-  + 6H+      -----> 3I2  + 6H2O

s2O3--  + I2 ------> S4O6-- + 2 I-

so IO3-   ie equivalent to 3 I2 equivalent to 3 S2O3--

moles of thiosulphate = 30 x 0.5/1000  = 15 x 10-3
moles of iodate = 15 x 10-3 /3  = 5 x 10-3

25 cm3  =====  5 x 10 -3
1000  ======= 5 x 10-3   x  1000/25

0.2 mol dm-3

sorry about the upper and lower case I can't do them

sorry i don't know how to do upper and lower cases

[conquerpro]

does anyone know what i should do about the mass spectra and ir chapter?im really confused when it comes to observing the peak.should i memorize the nature of the peaks of the compounds or what?

[NotAbod]

No, do not memorise it. Try to understand it. Practice questions about them and read the examiner reports. They are very easy, you only need to understand them. Also, you can try searching youtube for videos that may help you understand better.
Sorry, I forgot about it, been a year :/

[conquerpro]

can anyone please explain how to make an overall redox equation?i know that you need to combine the 2 equations.but what do you do after that?i need the full detailed explanion ASAP.please someone.

[Suryaw1]

I can help you all. For electrolysis of aluminum from its oxide, u have to build the equation. Then use chemical calculation method.
For the half redox equation, give me a question. I will solve it and give the explanation.

[daniel@mahsa.edu.my]

what is the oxidation state of ozone O3?

Hi.  Dont worry.

Refresh your memeory: If its an element, the oxidation state is zero.

That helps knowing that oxidation state of P4, S8, O2, O3, Cl2, Br2, N2 as zero!

Good luck in your exams

Dan

[conquerpro]

can anyone solve this question?
a solid gives a red colour in a flame test and reacts with conc H2SO4 to produce steamy fumes,but no other gases.the solid could be
A.LiBr
B.SrCl2
C.CaCl2
D.NaCl
the answer is SrCl2.but as we know CaCl2 also gives a brick red colour with conc H2SO4.so why not CaCl2

[DrThamooth]

heyy
i need help in past papers x_x
june 2010 - Q19 a ii
i cannot solve it :/
 Ethanoic acid can be manufactured by the following reaction, which is carried out
between 150 °C and 200 °C.
CH3OH(g) + CO(g) = CH3COOH(g)
 (a) A mixture of 50.0 mol of methanol and 50.0 mol of carbon monoxide reaches
equilibrium at a pressure of 32.0 atm. At 175 °C, the equilibrium partial pressure of
ethanoic acid is 22.2 atm.

 (ii) Calculate the partial pressures of methanol and carbon monoxide at equilibrium.

[conquerpro]

can someone plzz solve this MCQ for me and explain?
a sample of swimming pool water contains 0.482 ppm of chlorine.this is equal to a percentage of
  A.0.000482
B.0.0000482
C.0.00000482
D.0.000000482
this is from edexcel chem 1
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[conquerpro]

can someone PLZZZZ tell me what  happens when zinc hydroxide reacts with H+ ions?cuz i know ZN(OH)2 is amphoteric and reacts with OH- ions to give ZN(OH)4 but what does it give when it reacts with H+ ions?

[astarmathsandphysics]

water I think