Chem Qs (1 Viewer)

[lyounamu]

Stupid chem assignment!

I have got a chem assignment that I need to do but I cannot get some info that are necessary for this task.

If you look at the glucose molecule, is it the intramolecular force that holds it or intermolecular force?

I think it is a intramolecular force that holds the glucose together. But in saying that, I am not 100% sure.

 

[lolokay]

Re: Stupid chem assignment!

intramolecular = within the molecule (eg C to O)

intermolecular = between molecules (eg one glucose molecule to another)

 

[lyounamu]

Re: Stupid chem assignment!

intramolecular = within the molecule (eg C to O)

intermolecular = between molecules (eg one glucose molecule to another)

Yep. Thanks for clarification.

By the way, anyone knows of a good website where I can view the atomic size for all elements and ions?

 

[lyounamu]

Re: Stupid chem assignment!

Anyone? I really need more info...

 

[lyounamu]

Calculate the heat released from the metal if 100ml of water increased temperature from 25 to 35 degrees celsius.

My working out is like the following:

q = m x c x triangle T
= 100 . 4.18 . 10
= 4180.

I don't know if I am right or not. Can anyone give me the units for the answer I found?

 

[lolokay]

q is energy so you would expect the units to be joules - and the expression backs this up: mass*energy per gram per degree*number of degrees

 

[bubblesss]

Calculate the heat released from the metal if 100ml of water increased temperature from 25 to 35 degrees celsius.

My working out is like the following:

q = m x c x triangle T
= 100 . 4.18 . 10
= 4180.

I don't know if I am right or not. Can anyone give me the units for the answer I found?

heat released = 100/1000 x 4.18 x 10to the power 3 x 10 =4180 joules

yes ur correct

 

[jellybelly59]

q is calculated in joules

 

[lyounamu]

q is energy so you would expect the units to be joules - and the expression backs this up: mass*energy per gram per degree*number of degrees

So, I am right, I guess? (on my calculation)

Thanks for the clarification.

On another note, can anyone tell me the benefits of repeating the experiment a minimum of 3 times.

I have got few ideas in mind but if someone could provide me with few more, it will be awesome. Thanks in advance.

 

[bubblesss]

So, I am right, I guess? (on my calculation)

Thanks for the clarification.

On another note, can anyone tell me the benefits of repeating the experiment a minimum of 3 times.

I have got few ideas in mind but if someone could provide me with few more, it will be awesome. Thanks in advance.

benefits of repeating an experiment would be to increase the reliability and accuracy of ur experiment. is that wat ur after?

 

[lyounamu]

benefits of repeating an experiment would be to increase the reliability and accuracy of ur experiment. is that wat ur after?

Ah~~~ I was hoping for other benefits.

 

[bubblesss]

Ah~~~ I was hoping for other benefits.

are u asking for benefits of a general chem experiment? or specific? because different experiments have different benefits.

 

[lyounamu]

How do we calculate polarity of a subtance, say water?

 

[lyounamu]

are u asking for benefits of a general chem experiment? or specific? because different experiments have different benefits.

Sorry for being misleading. I was asking for benefits of repetition for experiment to calculate the specific heat capacity of different metals.

 

[bubblesss]

Sorry for being misleading. I was asking for benefits of repetition for experiment to calculate the specific heat capacity of different metals.

ok i get it well the need for rpeating is because during your experiment there may hav been a loss of heat to the environment or heat may have been absorbed from the surroundings. by repeating we cam get a more accurate value of specific heat. hope i helped.

 

[lolokay]

How do we calculate polarity of a subtance, say water?

I think it's measured by placing the substance between the plates of a capacitor and then measuring the change in the electric field of the capacitor (caused by the lining up of the molecules so that +ve end faces -ve capacitor plate, -ve end faces +ve capacitor plate) then do some calculations of how many moles of the substance there are and whatever else and you get the polarity

also, if you know the geometric structure of the molecules, and the electronegativity of the elements you could make a theoretical calculation

 

[kaz1]

Re: Stupid chem assignment!

Yep. Thanks for clarification.

By the way, anyone knows of a good website where I can view the atomic size for all elements and ions?

Periodic Table

Click each element to see the atomic size.

You can type the ion you want in search.

 

[jellybelly59]

Re: Stupid chem assignment!

You could try to borrow SI chemical data books.

 

[lolokay]

we most likely don't, but no harm in learning it anyway

 

[undalay]

A general polarity of any molecular can be estimated relatively accurate by looknig at the shape of the molecule, and the difference of electronegativity between bonding atoms.