Qualification > Sciences
ALL CIE CHEMISTRY DOUBTS HERE !!
Twinkle Charms:
(i) The material X can be pumice or ceramic used such as brick or broken crockery. Write the chemical name of the substance that might be present in one of these materials.
(ii) Suggest why X needs to be heated strongly?
(iii)The material X becomes black in color. Suggest what substance is responsible for this black color and how it arises in the reaction?
Hissa:
I have some few questions :(
1) Increasing the temperature of the propanoic acid solution causes the pH to decrease.
What does this tell you about the enthalpy of dissociation?
2) Why is an indicator usually added in iodine/thiosulphate titrations but not in titrations involving potassium managanate (VII)?
Alpha:
Just telling you not to wait for Deadly_King; he'll be absent for the week-end. :)
Arthur Bon Zavi:
--- Quote from: Twinkle Charms on November 19, 2010, 07:36:16 pm ---(i) The material X can be pumice or ceramic used such as brick or broken crockery. Write the chemical name of the substance that might be present in one of these materials.
(ii) Suggest why X needs to be heated strongly?
(iii)The material X becomes black in color. Suggest what substance is responsible for this black color and how it arises in the reaction?
--- End quote ---
I am trying :
(i) Silicon(IV) carbide (SiC) / Silicon(IV) nitride (Si3N4).
(ii) To overcome it's melting point (their melting points are considerably high)/ To have it in the liquid state.
(iii) Oxygen (or oxygen compound) from atmosphere, by heating.
Ivo:
How would one attempt Qs. 4, 5 and 6 on the worksheet? Please click here for the worksheet.
Many thanks in advance!
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