Prelim Chem Thread (1 Viewer)

[eyeseeyou]

11. A compound is a pur substance that is made from more than one atom chemically joined together in a fixed ratio. Why?
12. Why do compounds have a molecular formula?
13. Why do compounds be decomposed into its elements by chemical means?
14. Why do compounds display different chemical and physical properties compares to the elements they are made from?
15. Why are mixtures impure?
16. Why do mixtures consist of 2 or more substances?
17. Their composition is not fixed as the components can be present in varying proportions (of mixtures). Why?
18. Why can the different omponents be separated by using physical separating techniques?
19. Why can mixtures not be represented using a chemical formula?
20. Why can mixtures be classified as homogenous or heterogenous?

 

[eyeseeyou]

21. Why does a homogenous mixture have a uniform composition and properties throughout?
22. Why are the molecules (in a homogenous mixture) evenly mixed throughout?
23. Why does a heterogeneous mixture have a variable composition and properties throughout?
24. Why is the biosphere where living organisms found?
25. Why are living things composed of cells and within these cells, there are many compounds and elements such as carbohydrates, fats, and proteins?
26. The most common elements found in the body are carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur. Why?
27. In the body there are a range of carbohydrates, proteins and fats. Why? (this is regarding mixtures)
28. The lithosphere includes the earth’s uppermost solid mantle and the crust. Why?
29. The lithosphere consists mainly mixtues of different of different mineral sediment with sand, rock and soils oxides and oxygen compounds? Why? These substances make up the mixtre? Why?
30. Why does the hydrosohere include all the waters on the earth’s surface. i.e. oceans, rivers, lakegroundwater and atmospheric mixture?

 

[eyeseeyou]

31. Why is water the most abundant compound in this atmosphere?
32. Why does the sea contain many dissolved minerals and salts?
33. Why is a sieve a tool that has many small holes?
34. Why is it usred to separate smaller particles from larger ones or solids from liquids?
35. When sieving, why are components separated based upon different particle size?
36. In sieving, why do the larger particles get trapped in the sieve while the smaller particles are able to pass through?
37. In magnetic separation, why is it strictly separated based on particle size?
38. Why in magnetic separation, the separation is based on ferromagnetism?
39. Why is ferromagnetism the basic magnetic property where a substance is naturally attracted to a magnet?
40. When the magnet is stirred around in the mixture, ferromagnetic substances will attract to the magnet. Why?

 

[eyeseeyou]

41. Sedimentation is based upon the density of the compounds. Why?
42. Why will the heavier solids sink to the bottom of the container?
43. Why would decantation follow sedimentation (in that sense if you get what I mean)?
44. Why is the solid left behind when the liquid is poured out from the container?
45. Why is filtration based on the insolubility of the components and particle size?
46. When the mixture is poured through the liquid, the liquid passes through and is known as the filtrate while the solid is left behind in the filter paper (the residue). Why?
47. Centrifugation is separating substances based upon density and immiscibility. Why?
48. Why is centrifugation a process which involves the use of the centrifugal force for the sedimentation of heterogeneous mixtures?
49. Why (in centrifugation) is the force produced causes the suspended substances to sink to the bottom where the substances at the bottom are denser?
50. Why is this process usually used to separate blood into different components?

 

[eyeseeyou]

51. In evaporation, the mixtures are separated based upon boiling point. Why?
52. Why in evaporation, would the more volatile boiling point evaporate first?
53. Why does high volatily=low boiling point?
54. Why is crystallisation separated based on solubility?
55. Why is crystallisation conducted when the solution contains more than one solute?
56. Why do different solutes have varying degrees of solubility?
57. Why would different solutes crystallise at different times when the liquid evaporates?
58. Why would substances with a low solubility crystallise first?
59. Why does distillation use boiling points to separate?
60. In distillation ,why would the more volatile liquid evaporate and travel up the column into the condenser where it is condensed back into liquid form and is collected in a separate beaker?

 

[eyeseeyou]

61. Why is fractional distillation used when liquids have similar boiling points?
62. Why does fractionating column allow for there to be multiple condensations?
63. Why does the more volatile substances condense first and reach the top of the fractionating column?
64. Why does the higher boiling point substance vaporise and condenses more readily in the fractionating column and drips back into the distilling flask?
65. Why does a separating funnel separate immiscible liquids based upon density?
66. Why is the mixture that is formed heterogenous and why are there two layers?
67. Why is the denser layer at the bottom?

 

[eyeseeyou]

Need help. Got an exam coming up

 

[Shuuya]

31. Why is water the most abundant compound in this atmosphere?
32. Why does the sea contain many dissolved minerals and salts?
33. Why is a sieve a tool that has many small holes?
34. Why is it usred to separate smaller particles from larger ones or solids from liquids?
35. When sieving, why are components separated based upon different particle size?
36. In sieving, why do the larger particles get trapped in the sieve while the smaller particles are able to pass through?
37. In magnetic separation, why is it strictly separated based on particle size?
38. Why in magnetic separation, the separation is based on ferromagnetism?
39. Why is ferromagnetism the basic magnetic property where a substance is naturally attracted to a magnet?
40. When the magnet is stirred around in the mixture, ferromagnetic substances will attract to the magnet. Why?

I haven't looked through the rest of your questions, but I'm not sure if you're being serious with that one

It's good to ask why, but come on...

 

[InteGrand]

Need help. Got an exam coming up

Sixty-seven questions?

 

[Green Yoda]

Sixty-seven questions?

Thats more than my trig questions in maths thread

 

[BandSixFix]

31. Why is water the most abundant compound in this atmosphere?
32. Why does the sea contain many dissolved minerals and salts?
33. Why is a sieve a tool that has many small holes?
34. Why is it usred to separate smaller particles from larger ones or solids from liquids?
35. When sieving, why are components separated based upon different particle size?
36. In sieving, why do the larger particles get trapped in the sieve while the smaller particles are able to pass through?
37. In magnetic separation, why is it strictly separated based on particle size?
38. Why in magnetic separation, the separation is based on ferromagnetism?
39. Why is ferromagnetism the basic magnetic property where a substance is naturally attracted to a magnet?
40. When the magnet is stirred around in the mixture, ferromagnetic substances will attract to the magnet. Why?

because the big pieces are too big to pass through the tiny holes of the sieve #StateRankInChem

 

[porcupinetree]

21. Why does a homogenous mixture have a uniform composition and properties throughout?
22. Why are the molecules (in a homogenous mixture) evenly mixed throughout?
23. Why does a heterogeneous mixture have a variable composition and properties throughout?
24. Why is the biosphere where living organisms found?
25. Why are living things composed of cells and within these cells, there are many compounds and elements such as carbohydrates, fats, and proteins?
26. The most common elements found in the body are carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur. Why?
27. In the body there are a range of carbohydrates, proteins and fats. Why? (this is regarding mixtures)
28. The lithosphere includes the earth’s uppermost solid mantle and the crust. Why?
29. The lithosphere consists mainly mixtues of different of different mineral sediment with sand, rock and soils oxides and oxygen compounds? Why? These substances make up the mixtre? Why?
30. Why does the hydrosohere include all the waters on the earth’s surface. i.e. oceans, rivers, lakegroundwater and atmospheric mixture?

Same

 

[eyeseeyou]

Thats more than my trig questions in maths thread

lol ikr

 

[eyeseeyou]

because the big pieces are too big to pass through the tiny holes of the sieve #StateRankInChem

nek minnit...

 

[eyeseeyou]

Bro hurry up someone help me plz or else I'm a goner

 

[InteGrand]

Bro hurry up someone help me plz or else I'm a goner

Most of your Q's can be answered in two words: "by inspection".

 

[eyeseeyou]

Most of your Q's can be answered in two words: "by inspection".

really, but there's reasoning to them isn't there?

 

[InteGrand]

really, but there's reasoning to them isn't there?

In the end, they actually will come down to inspection mostly. By this I mean, scientists observe ("inspect") the world via experiments and then may try and propose models explaining the 'why'. If you keep asking why though it'll probably come down to 'by inspection', since we'll arrive at the observation stage.

 

[eyeseeyou]

Someone pls help me

 

[eyeseeyou]

WOW did noone actually bother to help me