February 20, 2017

Homework Help: Science-Experiment-Questions

Posted by Sara on Wednesday, April 7, 2010 at 10:08am.

I did an experiment on a burning candle, and I need help with some of the questions. Thank you very much in return. Please no websites.--more information would be appreciated, thanks:-)

I'll list everything of what we went through.

-1 standard candle
-safety goggles
-2 pieces copper wire
-1 petri dish
-cobalt cholride paper
-100 ml baker
-250ml flask
-rubber stopper

Part 1:

1. Make a data table to for each part to record your observations.

2.observe the properties of the unlit candle. what states of matter are present? measure the mass and the length of the candle. measure the mass of the candle and the petri dish together. record ur observations in ur data table.

3.put your safety goggles and apron on. light the candle and melt 2 or 3 drops of wax in the centre of the dish. stick the base of the candle in the wax before it cools so that the candle can stand by itself.

4.time ur observation of the burning candle for 5 min. make careful observations of the flame noting any different regions in it. make 10 or more observations, and record them in ur data table. start ur observations: how many states of matter do you see? where does the burning take place? what is actually burning?

5.after 5 min, extinguish candle light a match in the smoke above the andle. record ur observations.

6.determine length of candle and mass of candle and petri dish. record ur measurements.

Part 2:

7.light candle again. hold a straight piece of opper wire above, but not in, the flame. what do u observe?

8.make a coil with a new piece of copper wire by wrapping the copper wire around a pensil. with tongs , lower the coil upright over the tip of the flame without touching the candle wax. be prepared for the flame to go out. if it does, quickly remove the coil. record ur observations.

Part 3:

9. Test a strip of cobalt chloride test paper with a drop of water to see what happens. light the candle. carefully invert a flask over the candle flame and hold it until the flame is extinguished. be careful not to let the flask get so hot that you get burned. test the inside of the flask with a cobalt chloride test strip. record ur observations.

10. pour tap water to a depth of 1 cm into the petri dish that is holding the candle. light the candle. carefully lower the 250ml flask over the candle so that the mouth is completetly below the surface of the water. leave it for 1 min and record ur observations.

11.Lift the flask out of the water, turn it upright, and add about 25 ml of limewater. put the rubber stopper in the flask and gently swirl for 1 min. record ur observations.

properties of the unlit candle-I got:
-the unlit candle is in the state of a solid, it is clear colour.

Please add any other info, thanks

These were the observations I got for Part 1:

-candle is going from soild to a liquid from top.
-as candle shrinks, flame grows
-flame blew at the wick, yellow on outside
-the wick is burning
-solid, liquid, and gas are present
-static, and candle lit again
-the wick is black

I need atleast 2 more other observations. I don't quite remember what else had happened, so if anything else was supposed to occur please list it down, thanks

Part 2 observations:
-copper wire arises the flame high
-you can see smoke arising from the flame
-from top the flame goes dark in colour
-sparks appear

could I also right heat is being radiated. I didn't get too many observations for this one, --help needed.

Part 3 observations:
what was supposed to happen to the cobalt chloride test paper?

-it never made an difference towards anything
-as the water is put into the petri dish, bubbles arise
-flask sucks up the water from the petri dish.

any other information on this would be greatly appreciated, thanks


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. More changes would be appreciated. I am kind of having troubles identifying which changes are chemical and which are physical--so help would be appreciated on this as well.--I need more changes.

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.

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?

Please take all your time to go through this. I really need help with some of the questions and observations. Thank You so much:-)

Science-Urgent - bobpursley, Tuesday, April 6, 2010 at 8:47pm
Part 1. Did you notice heat coming from the flame? Light?

Part 2. What color was the sparks?

Part 3. Cobalt Cloride paper is used to test for water or water vapor (steam). It turns blue when wet. You should have noticed the gas in the flask contained water vapor.

Part 4. The wick was not burning, it was the gasified wax (solid>liquid> in the hot wick to gas, and the gas was burning with oxygen in the air. The wick was burning slightly as a side note.

You should have noticed that water and carbon dioxide (tested for in limewater) were the products of the wax burning.

Science-Urgent - Sara, Tuesday, April 6, 2010 at 8:52pm
Part 1. Yes I did.

Part 2. They were deep orange in colour--like fire

Thank you. Can you also check my questions please

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