Chem syllabus question (3 Viewers)

[lyounamu]

· Explain how water’s ability to absorb heat is used to measure energy changes in chemical reactions

Does anyone have decent notes on this?

I have done it but I am lacking info. Thanks in advance.

· • Identify that nuclei, mitochondria and chloroplasts contain DNA

I am sorry to bother you guys again. But does anyone have notes on this one by the way? (this is from the Biology syllabus)
I have only got 3 lines on this. I basically said that mitochondria and chloroplasts contain DNA because DNA instructs them to manufacture products required for th cell. And I don't think that's sufficient.

Extra help would be greatly appreciated.

 

[lsam]

· Explain how water’s ability to absorb heat is used to measure energy changes in chemical reactions

Does anyone have decent notes on this?

I have done it but I am lacking info. Thanks in advance.

· • Identify that nuclei, mitochondria and chloroplasts contain DNA

I am sorry to bother you guys again. But does anyone have notes on this one by the way? (this is from the Biology syllabus)
I have only got 3 lines on this. I basically said that mitochondria and chloroplasts contain DNA because DNA instructs them to manufacture products required for th cell. And I don't think that's sufficient.

Extra help would be greatly appreciated.

For the first one, it is important to mention the calorimeter. When the reaction occurs at calorimeter (assuming that it is a perfectly insulated one), there is no loss of the heat. By using water as the substance that is being heated or (losing heat) you can measure the energy changes (or enthalpy).

For the 2nd one, I don't have much either. I think that's sufficient. Just expand on those points and be specific. Say like: "DNA is a nucleic acid that determines the heredity of a cell. DNA controls what proteins are made in the cell or not and hence this affects the whole structure (proteins make up our bodies) and funciton of the cell (enzymes take part in chemcial reactions in the cell). Therefore, by having DNA, mitochondria and chloroplast can undertake actions that suit the cell's own needs"

 

[marcquelle]

you could also mention with Chem. That it can also read weither it was an exothermic or endothermic reaction.

With the DNA, you can aslo speak of the differing DNA that each contains as an element of evolution from prokaryotic to eukaryotic cells, and that the inclusion of Each dna sequence alters the dna sequencing of the organism during the process of evolution if you wish. thiugh this is A COMPLEX IDEA TO GET.

 

[lyounamu]

you could also mention with Chem. That it can also read weither it was an exothermic or endothermic reaction.

With the DNA, you can aslo speak of the differing DNA that each contains as an element of evolution from prokaryotic to eukaryotic cells, and that the inclusion of Each dna sequence alters the dna sequencing of the organism during the process of evolution if you wish. thiugh this is A COMPLEX IDEA TO GET.

I think we are flowing into too much details there. And I think it is the nucleotides of nucleic acid that determines DNA and DNA determines the actual sequence of amino acids in proteins.

Thanks by the way.

Thanks to sam as well.

 

[marcquelle]

I think we are flowing into too much details there. And I think it is the nucleotides of nucleic acid that determines DNA and DNA determines the actual sequence of amino acids in proteins.

Thanks by the way.

Thanks to sam as well.

thats alright as isam said what you have is correct but theres, tonnes of info about though some of which you can add others which i choose to omit lol, bio has many complex elements, but still enjoyable

 

[Continuum]

· Explain how water’s ability to absorb heat is used to measure energy changes in chemical reactions

I'll just copy and paste this short thing from my little note thingy:

Calorimeter
A colorimeter is a device for measuring the heat absorbed or released during a chemical or physical change. It consists of a thermally insulated container (where reaction occurs) containing a known mass of water (absorbs or provides heat energy, allowing us to determine the change in enthalpy by measuring the change in temperature). The total heat produced by an exothermic reaction is equal to the heat absorbed by the water and all the calorimeter parts within the insulated chamber. As the heat absorbed by the latter is fairly negligible, the overall change in enthalpy is calculated by measuring the change in temperature of the water combined with the mCAT equation. The same applies for endothermic reactions.

It's not really that important so yeah, I reckon a short summary like that is enough.

 

[Aerath]

What's a colorimeter? =\
Unless that's just a typo for calorimeter, although, a and o are so far apart on the keyboard. =\

 

[bored of sc]

· Explain how water’s ability to absorb heat is used to measure energy changes in chemical reactions

Water has a high specific heat capacity (the heat energy required to raise the temperature of a substance by 1 degree Kelvin). For this reason, it is useful as a material with which to measure energy changes in chemical reactions because it can absorb relatively large amounts of heat energy produced in these reactions without changing state.

If water had a lower specific heat capacity it may evaporate rapidly or boil and heat energy would be transferred to the surroundings. This heat lost by evaporation or boiling would therefore not be measurable.

Water is a non-toxic material whose volume and mass is easily measured.

Many chemical and physical processes take place in solution and can therefore be measured experimentally.

Reactions that take place in solution (e.g. the neutralisation of an acid by an alkali) can be carried out in a calorimeter. A polystyrene cup with an insulating lid can be used as a reaction vessel and the temperature rise measured with a thermometer.

If the heat energy produced by a combustion reaction (of fuel such as ethanol) is to be measured a known mass of water can be placed in a container and the water heated by burning a known mass of the fuel. The temperature rise of the water can be measured and the heat energy produced by the burning fuel calculated.


As for the DNA question, what dot-point is that?

 

[Continuum]

What's a colorimeter? =\
Unless that's just a typo for calorimeter, although, a and o are so far apart on the keyboard. =\

Haha, oh shit! Leave me alone.

 

[lyounamu]

Water has a high specific heat capacity (the heat energy required to raise the temperature of a substance by 1 degree Kelvin). For this reason, it is useful as a material with which to measure energy changes in chemical reactions because it can absorb relatively large amounts of heat energy produced in these reactions without changing state.

If water had a lower specific heat capacity it may evaporate rapidly or boil and heat energy would be transferred to the surroundings. This heat lost by evaporation or boiling would therefore not be measurable.

Water is a non-toxic material whose volume and mass is easily measured.

Many chemical and physical processes take place in solution and can therefore be measured experimentally.

Reactions that take place in solution (e.g. the neutralisation of an acid by an alkali) can be carried out in a calorimeter. A polystyrene cup with an insulating lid can be used as a reaction vessel and the temperature rise measured with a thermometer.

If the heat energy produced by a combustion reaction (of fuel such as ethanol) is to be measured a known mass of water can be placed in a container and the water heated by burning a known mass of the fuel. The temperature rise of the water can be measured and the heat energy produced by the burning fuel calculated.


As for the DNA question, what dot-point is that?

Sweet, man. Thanks!

The DNA one is the one from the Biology Syllabus. (the last dot-point of the Patterns in Nature module)

And big thank you to continuum as well!

 

[Aerath]

Haha, oh shit! Leave me alone.

LOL, so I take it it was a typo.

 

[lyounamu]

· Outline the history of the development of the Periodic Table characteristics of unknown including its origins, the original elements used to construct it and the predictions made after its construction

For this dot-point, did anyone put any info apart from dmitri mendeleev, meyer and moseley? (e.g. john newlands's law of octave and etc.)

I just want to see if I need to or not.

 

[Aerath]

The important person is Mendeleev. And I think you need 2 other scientists, so I used Newlands and Moseley.

 

[shaon0]

· Outline the history of the development of the Periodic Table characteristics of unknown including its origins, the original elements used to construct it and the predictions made after its construction

For this dot-point, did anyone put any info apart from dmitri mendeleev, meyer and moseley? (e.g. john newlands's law of octave and etc.)

I just want to see if I need to or not.

what module are you upto? Module 3?

 

[lyounamu]

what module are you upto? Module 3?

i've finished module 3 so i am doing some revision.

 

[bored of sc]

Aristotle stated that all matter was made up of four elements: Earth, wind, water and fire. (I think, this of off the top of my head)

According to Chemistry Contexts:

Lavoisier published a table of 33 elements.

Dobereiner reported that several groups, each containing three elements contained similiar physical and chemical properties (called this triads). He then grouped elements according to similiar chemical and physical properties.

Chancourtois constructed a table of elements in the form of a helix or 'telluric screw' on a vertical cylinder.

 

[Continuum]

ok...my class just finished module 3 but i finished module 4 so i don't have to do any chem work for a while

Ok?

 

[shaon0]

Ok?

Oh crap. I forgot to quote lyounamu.
sorry

 

[shaon0]

i've finished module 3 so i am doing some revision.

ok...my class just finished module 3 but i finished module 4 so i don't have to do any chem work for a while
Should you be revising any of your modules? I just do exercisises and module review from the textbook.

 

[jellybelly59]

LOL at u studious ppl... i can't do anything LOL how do u guys get out of holiday mode?