Q&A - P4 Science

[atutor2001]

Zack7:

on 2nd thought, i think i understand what you are gunning at.


you now must understand the definition of volume of air.

if each marble represents a molecule of air , say 1 marble = 1cm^3

if we had 10 marbles, then when we put into 1000cm^3 of box, then yes, you are right, we only have 10 marbles and the volume of it is 10cm^3

but the definition of air takes into account the free space between the air molecules too.

this is why when the gas has spread into the container, it is said to have a volume of 1000cm^3.

The concept of volume regardless whether it is gaseous, liquid or solid state will always take into account the empty space among the molecules. It is not limited to gaseous state only.

A more precise definition of volume that I can think of is :

Volume is the 3-dimensional space that the molecules (within a given mass of matter) can occupy.

Therefore, even in solid and liquid, the volume will also include empty spaces among the molecules. That explains why the volume of liquid water will increase when it is frozen into ice. It is because the tetrahedral structure of the water molecules in ice will create more empty spaces among the molecules than the planar structure of the water molecules in the liquid state.

It also explains why the volume of metal expands when heated. It is because the atoms will have more energy after heating and can then move further apart from each other, thus creating more empty spaces among them.

The volume of solid and liquid are fixed (definite) because of the bonds (attraction) among the molecules/atoms, which limit their movement, preventing them from occupying a bigger space. However, when a matter is in gaseous state, there is no bond among the molecules and they are free to move to anywhere. The only limit is the wall of the container. That is why the volume gases is always equal to the volume of the container that it is put in.

Hope this can clear all doubts on definition of volume of matter.

[Zack7]

ttyh:

In what way is the large intestines and small intestines similar in terms of special features they have to facilitate absorption of materials?

intestines are folded in special ways to increase surface area for maximal absorption through diffusion.

[Zack7]

ttyh:

In a digestive system, which organ will one find the sharpest drop in the amount of undigested food left? Why?

i don't really understand what mean by the 'sharpest drop in the amount of undigested food left'

but i guess its the intestines. because that is where your undigested food gets removed into the colon, hence there is a 'sharp drop?'

[Zack7]

atutor2001:

Zack7:

on 2nd thought, i think i understand what you are gunning at.


you now must understand the definition of volume of air.

if each marble represents a molecule of air , say 1 marble = 1cm^3

if we had 10 marbles, then when we put into 1000cm^3 of box, then yes, you are right, we only have 10 marbles and the volume of it is 10cm^3

but the definition of air takes into account the free space between the air molecules too.

this is why when the gas has spread into the container, it is said to have a volume of 1000cm^3.

The concept of volume regardless whether it is gaseous, liquid or solid state will always take into account the empty space among the molecules. It is not limited to gaseous state only.

A more precise definition of volume that I can think of is :

Volume is the 3-dimensional space that the molecules (within a given mass of matter) can occupy.

Therefore, even in solid and liquid, the volume will also include empty spaces among the molecules. That explains why the volume of liquid water will increase when it is frozen into ice. It is because the tetrahedral structure of the water molecules in ice will create more empty spaces among the molecules than the planar structure of the water molecules in the liquid state.

It also explains why the volume of metal expands when heated. It is because the atoms will have more energy after heating and can then move further apart from each other, thus creating more empty spaces among them.

The volume of solid and liquid are fixed (definite) because of the bonds (attraction) among the molecules/atoms, which limit their movement, preventing them from occupying a bigger space. However, when a matter is in gaseous state, there is no bond among the molecules and they are free to move to anywhere. The only limit is the wall of the container. That is why the volume gases is always equal to the volume of the container that it is put in.

Hope this can clear all doubts on definition of volume of matter.

... you just said that volume takes into account the free space regardless of the states and you give a 'more precise' volume definition that doesn't talk about free space?

but lets not be picky about definitions shall we? wiki has a better definition if anyone needs.

and there are intermolecular forces of attraction among molecules in the gaseous state. just that they are negligible at the normal regime, just like the free space in solids and liquids.

and if you like to clear more doubts, you might want to point out that water is a special case whereby it expands when cooled into a solid and contracts when heated into a liquid.
as opposed to your other example of a metal which expands when heated and contracts when cooled.

also, do you understand the asker's question? do you understand the point he is driving at? i find it funny that you threw out a ton of info that doesn't address his question.

he had a problem about the definition, not about pv= nrt etc. as per your previous posts.

[atutor2001]

Zack7:

ttyh:

In a digestive system, which organ will one find the sharpest drop in the amount of undigested food left? Why?

i don't really understand what mean by the 'sharpest drop in the amount of undigested food left'

but i guess its the intestines. because that is where your undigested food gets removed into the colon, hence there is a 'sharp drop?'

You seemed to have problem with comprehension. Allow me to explain it in simple English. \"Undigested food\" means those food that is not digested yet. \"amount of undigested food left\" means the amount of undigested food that can still be found. \"sharpest drop in the the amount of undigested food left\" would therefore mean that the decrease in the amount of undigested food that can still be found is the greatest. By the way, in case you do not know,\"sharp drop\" means greatest decrease.

Therefore, your answer is wrong, it is the stomach. Common sense will tells us that most digestion occurs in the stomach where digestive juice are added and the churning and squeezing actions of the stomach will break down the food into liquid form and into simpler substances.

Therefore, for a given amount of food eaten, if we compare the amount of undigested food at the entry to the stomach compared to the amount of undigested food at the exit of the stomach, we will find the \"sharpest drop i.e. greatest decrease.

I think it is your language handicap. No wonder you always have weird interpretations.

[Zack7]

atutor2001:

Zack7:

[quote=\"ttyh\"]In a digestive system, which organ will one find the sharpest drop in the amount of undigested food left? Why?

i don't really understand what mean by the 'sharpest drop in the amount of undigested food left'

but i guess its the intestines. because that is where your undigested food gets removed into the colon, hence there is a 'sharp drop?'

You seemed to have problem with comprehension. Allow me to explain it in simple English. \"Undigested food\" means those food that is not digested yet. \"amount of undigested food left\" means the amount of undigested food that can still be found. \"sharpest drop in the the amount of undigested food left\" would therefore mean that the decrease in the amount of undigested food that can still be found is the greatest. By the way, in case you do not know,\"sharp drop\" means greatest decrease.

Therefore, your answer is wrong, it is the stomach. Common sense will tells us that most digestion occurs in the stomach where digestive juice are added and the churning and squeezing actions of the stomach will break down the food into liquid form and into simpler substances.

Therefore, for a given amount of food eaten, if we compare the amount of undigested food at the entry to the stomach compared to the amount of undigested food at the exit of the stomach, we will find the \"sharpest drop i.e. greatest decrease.

I think it is your language handicap. No wonder you always have weird interpretations.[/quote]woah, looks like you don't understand simple english too

i already said 'i don't really understand' and i 'guess', which means i may be wrong.

i never claimed to clear anyone's doubt? lol... unlike a certain someone.

and looks like you still enjoy employing personal attacks when arguing. what a sad case. too much intellect makes you snobbish?

or did your ego get pricked?

[atutor2001]

Zack7:

woah, looks like you don't understand simple english too

i already said 'i don't really understand' and i 'guess', which means i may be wrong.

i never claimed to clear anyone's doubt? lol... unlike a certain someone.

and looks like you still enjoy employing personal attacks when arguing. what a sad case. too much intellect makes you snobbish?

or did your ego get pricked?

Just a reminder. This thread is for science. Please follow the rule of this forum and do not create a reply that has totally no bearing on science. Thank you.

[teh_oh]

Hi,

Appreciate assistance on the following question.


http://i44.tinypic.com/5lqxbm.jpg\">

Child's answer is 4 as it is not conclusive that metal bar TU is made from a magnetic material.
Ans Key: 1

Thank you.

[teh_oh]

Hi,

Appreciate assistance on the following question
http://i44.tinypic.com/htwlk5.jpg\">
Child's answer is Set up B and C.
Ans Key: Setup A and C.

Thanks.

[ttyh]

Zack7:

ttyh:

In what way is the large intestines and small intestines similar in terms of special features they have to facilitate absorption of materials?

intestines are folded in special ways to increase surface area for maximal absorption through diffusion.

Thanks. I just couldn't get this answer after googling...
I will wait for the answers back from the teacher.... :xedfingers: