Question

Someone please help me with 3 science questions!
1) A student tested a sample of carbon (C) by combining it with water. There was no reaction between the carbon and water. The student concluded that carbon must be a group 18 element, since it was unreactive. State whether you agree with the student's reasoning, and explain why or why not.

Answer 1

2) A student states that Earth would be no different if water did not expand when it freezes. Do you agree with this statement? Explain your answer.
3) A student is deciding which chemicals are acids by measuring their pH. He sees that a solution of CO2 has an acidic pH. He decides that he must have contaminated his sample. He thinks that CO2 could not create hydrogen ions in the solution since it contains no hydrogen atoms. Explain what is incorrect about the student’s reasoning.

Answer 2

hi,
for ur first question... let me ask this
it's reasonable to conclude that an element belongs to the group 18 if it is nonreactive... but is it reasonable to justify it that way just because it does not reacts with water ?

Answer 3

No.

Answer 4

yep... Carbon not reacting with water only leave with us with the conclusion that carbon is less reactive because only highly reactive elements reacts with water.....
so the students conclusion is wrong.. ya got that ?

Answer 5

Yes, thank you. (:

Answer 6

Can you also help with the second one or no?
I think I figured out the third one on my own after really thinking about it and doing some research.

Answer 7

hmmmm.... for the second one... do u know about density ?

Answer 8

Kind of, sort of.

Answer 9

density = mass / volume... but whats important with density is that objects with less density floats on which r with higher density...
also density can be simply state as the mass of a unit volume... and density is the main reason that make ice floats on water....!!!
if we take 1 cubic centimeter of ice and 1 cubic centimeter of water the amount of ice particle is less than amount of water particles in that volume of 1 cubic centimeter. It s because that h20 particles expand when they form ice.... so the density of ice ice lesser than water.. so ice floats on water...
but if h20 doesn't expand... OPS... ice will no longer floats on water and i wander how will earth looks like then ???? lol

Answer 10

Alright got it, thank you!