To: Bobpursely

posted by .

You helped me with my observations yesterday, but I need help with my questions as well. I tried to answer as many as I could by myself, but I'm having difficulties understanding some. Pointing me towards the right direction would be helpful, thanks.

Questions:

Which changes that u noted in step 4 were physical? which were chemical?

I wrote: Changes in step 4 which were physical were the candle melting and the flame growing. Changes in step 4 which were chemical were the oxygen and the wick burning.


I am kind of having troubles identifying which changes are chemical and which are physical so I'm not sure which other occured changes were physical and which were chemical.

What evidence showed the release of energy? what forms of energy were produced by the burning candle? where was this energy in the unlit candle?

I wrote:
The flame growing hotter and hotter; heat is given off. This energy was in the wick --Please correct me if I'm wrong, thanks

based upon your analysis of your observations in Part 3, what are 2 substances produced by the combustion of the candle?

-I don't get this question-- i don't know the answer. i'll guess and say that bubbles were produced.

How does the mass of the candle change during combustion, explain this change in mass.?????????????????

Is it because of the wax starting to melt?

is there any evidence that the candle needs something from the air to help it burn? what might this something be?

- I don't get the first part but is the second one oxygen and hydrocarbon?

  • To: Bobpursely -

    You did not read my response.

    Physical changes: wax melted, then wax vaporized.

    CHemical change: wax vapor and oxygen in air changes to combustion products. THe cobalt paper tested for water vapor in the "fumes", and the limewater tested for carbon dioxide. So the output of the combustion was water and carbon dioxide.

    The mass of the candle changes because it is consumed in the burning. As for a evidence that something in the air was contributing to the burning, didn't the candle smother, or at least reduce the burn rate, when you put the coil down over it to shut off the air?

  • To: Bobpursely -

    Sara -- if you expect us to help you, you must thoroughly read all responses. It's discouraging for us to post an answer -- only to find that the student has ignored it.

  • To: Bobpursely -

    sorry Ms. Sue, sorry bobpursley for that inconvenience.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Math

    I'm having trouble understanding equivalent fractions. I'm getting frustated with myself, I feel so stupid for not understanding it. Here's the 2 questions I have to answer: 1. Find a number for x in 18/27 = x/3 so that the fractions …
  2. Biology

    Can you provide me with a simple understanding of fick's law. Basically just for a grade 11 student to understand what symbols mean what and the general understanding. I cant seem to piece it together myself but need to have a basic …
  3. accounting

    In what segment did Enron start having operation difficulties?
  4. Accounting

    In what segment did Enron start having operation difficulties?
  5. English

    1. Mother Teresa helped many people in India. (In this sentence, what is the part of speech of 'in India?
  6. Psychology

    So my class watch this movie called Boys Do Not Cry (Boys Don't Cry) and now i have two write a 7 page paper. I am having some difficulties trying to answer this questions Please help me giving some ideas of what i could write. •Describe …
  7. Science

    I have two questions that I need some help with please. 1) Developing a scientific understanding of a natural phenomenon typically begins by A)making a prediction B)Testing a hypothesis C)proving an answer or D) making an obvservation. …
  8. Science 7R - Worksheet (Q5)

    ********* Sorry I post too much question but these are the questions I'm having trouble with, the other questions on my science worksheet i done it by myself This is the last one I need help with and that's it E. How is the structure …
  9. English

    I have an essay about difficulties in life which is based on a book I read with my class. I am having trouble finding difficulties or adversities I have had in my life. Can you please give me some examples of difficulties that you, …
  10. Math (again)

    Sorry...I forgot to include all of the details for one of my previous questions the complete problem is: 1. Yesterday Josh sold some boxes of greeting cards. Today he sold seven boxes. If he sold 25 boxes in all, how many did he sell …

More Similar Questions