Topic: HELP!!!! Calling all science nerds!!

[ohcheap1]

1. Give as example of a chemical change produced by:
a) Light-
b) Electricity-
c) Heat-

2. How would you show that heating a platinum wire in air is a phsical change? Explain.

[hmed2390]

Doing your daughter's homework again for her cheapy? I know that sudden spark of interest in chemistry isn't solely lust driven now.  

[ohcheap1]

Amen!!! You got my number Hmed now just give her an answer or a place to start to find an answer. Pleeeeeeeease......

[JackFrost]

1. Give as example of a chemical change produced by:
a) Light - Photosynthesis
b) Electricity - A battery
c) Heat - Bread

2. How would you show that heating a platinum wire in air is a phsical change? Explain.

I'm really not sure on this one

[ohcheap1]

1. Give as example of a chemical change produced by:
a) Light - Photosynthesis
b) Electricity - A battery
c) Heat - Bread

If that ^ is correct is the following v also? This is one she already completed.
2. Give an example of a chemical chage which produces:
a) Light and heat - Lighting a match
b) Electricity- Battery
c) Mechanical energy- burning gasoline (as fuel)

[xtopave]

1)

a) I thought of photosynthesis too but here's another: changes on billirrubine (I don't know how to spell it in English) structure when you expose an icteric baby to ultraviolet light.

b) Electrolysis (contrary of a battery)

c) Coagulation (denaturalization) of proteins by heat (ex: egg)

2) When you stop the process the qualities of the material (platinum wire in this case) aren't altered. Opposed as when a chemical change takes place.
Does this make sense?

[xtopave]

If that ^ is correct is the following v also? This is one she already completed.
2. Give an example of a chemical chage which produces:
a) Light and heat - Lighting a match
b) Electricity- Battery
c) Mechanical energy- burning gasoline (as fuel)

The third isn't correct. Electric energy taken from a waterfall is an example of mechanical energy transformed in another kind. Also rubbing hands generating heat could be an example.

[ohcheap1]

2) When you stop the process the qualities of the material (platinum wire in this case) aren't altered. Opposed as when a chemical change takes place.
Does this make sense?

I know its difficult for you to analyse and then translate into english but this one is alittle hard for her to grasp.  Geesh.....you really do know everything xtopave!!!

[xtopave]

First of all I misinterpreted point 3). If what you mean is the transformation of chemical energy (fuel) into mechanical energy (movement of the car) then it's correct.

Second: A physical change doesn't alter the characteristic of matter as opposed to a chemical change which does exactly that. The platinum wire before and after the heating is absolutely exactly the same.

[jackalope21]

2. How would you show that heating a platinum wire in air is a phsical change? Explain.

If a shiny platinum wire is heated, it will glow with a red color. But when it is removed from the flame, it regains the properties it had before heating. This color change is then a physical change because the composition and physical properties remain the same.

[ohcheap1]

Group Hug!!!

I thank you and Anna thanks you.

[xtopave]

I hope it helped somehow. I thought of more things later but I remember how it was when doing homework: just do it and move on.    Can I ask how old is she?

[ohcheap1]

15 and in advanced placement chemistry. She had completed the whole 100 question homework assignment but those 2 stumped her. Of course she completely understands now that she sees the answers but I think her brain was just on overload.

[xtopave]

100 questions like that when you're 15 can crash your brain. 

[hmed2390]

Awesome everybody.
Sorry OC1, I fell asleep before I could respond  
But you got much better answers than I would have come up with