

 Chemistry grade 10 [caps]

The properties of matter
Let us now look at what we have learned about chemical
bonds, intermolecular forces and the kinetic theory of matter, and see whetherthis can help us to understand some of the macroscopic properties of materials.

Melting point
Melting point
 The temperature at which a
solid changes
its phase or state to become a
liquid . The
process is called melting and the reverse process (change in phase from liquidto solid) is called
freezing .
In order for a solid to melt, the energy of the particles
must increase enough to overcome the bonds that are holding the particlestogether. It makes sense then that a solid which is held together by strong
bonds will have a
higher melting point
than one where the bonds are weak, because more energy (heat) is needed to breakthe bonds. In the examples we have looked at metals, ionic solids and some
atomic lattices (e.g. diamond) have high melting points, whereas the meltingpoints for molecular solids and other atomic lattices (e.g. graphite) are much
lower. Generally, the intermolecular forces between molecular solids are
weaker than those between ionic and
metallic solids.

Boiling point
Boiling point
 The temperature at which a
liquid changes
its phase to become a
gas . The process is
called evaporation and the reverse process is called condensation
When the temperature of a liquid increases, the average
kinetic energy of the particles also increases and they are able to overcomethe bonding forces that are holding them in the liquid. When boiling point is
reached,
evaporation takes place and some
particles in the liquid become a gas. In other words, the energy of theparticles is too great for them to be held in a liquid anymore. The stronger the
bonds within a liquid, the higher the boiling point needs to be in order tobreak these bonds. Metallic and ionic compounds have high boiling points while
the boiling point for molecular liquids is lower.The data in
[link] below may help you to understand some of
the concepts we have explained. Not all of the substances in the table aresolids at room temperature, so for now, let's just focus on the
boiling points for each of these substances. What do
you notice?
The melting and boiling
points for a number of substances
Substance 
Melting
point (
${}^{\xb0}\mathrm{C}$ ) 
Boiling point (
${}^{\xb0}\mathrm{C}$ ) 
Ethanol (
${\mathrm{C}}_{2}{\mathrm{H}}_{6}\mathrm{O}$ ) 

114,3 
78,4 
Water 
0 
100 
Mercury 
38,83 
356,73 
Sodium chloride 
801 
1465 
You will have seen that substances such as ethanol, with relatively weak
intermolecular forces, have the lowest boiling point, while substances withstronger intermolecular forces such as sodium chloride and mercury, must be
heated much more if the particles are to have enough energy to overcome theforces that are holding them together in the liquid. See the
section below for a further exercise on boiling point.

Density and viscosity
Density and viscosity is not in CAPS  Included for Completeness
Density
 Density is a measure of the mass of a substance per
unit volume.
The density of a solid is generally higher than that of a liquid
because the particles are held much more closely together and therefore thereare more particles packed together in a particular volume. In other words, there
is a greater mass of the substance in a particular volume. In general, densityincreases as the strength of the intermolecular forces increases.
Viscosity
 Viscosity is a measure of how resistant a liquid is to
flowing (in other words, how easy it is to pour the liquid from one container toanother).
Viscosity is also sometimes described as the 'thickness' of a fluid.
Think for example of syrup and how slowly it pours from one container intoanother. Now compare this to how easy it is to pour water. The viscosity of
syrup is greater than the viscosity of water. Once again, the stronger theintermolecular forces in the liquid, the greater its viscosity.
Questions & Answers
find the 15th term of the geometric sequince whose first is 18 and last term of 387
The given of f(x=x2. then what is the value of this f(3) 5f(x+1)
hmm well what is the answer
Abhi
how do they get the third part x = (32)5/4
can someone help me with some logarithmic and exponential equations.
sure. what is your question?
ninjadapaul
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X6)^2
so it's 20 divided by X6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
is it a question of log
Abhi
I rally confuse this number And equations too I need exactly help
salma
But this is not salma it's Faiza live in lousvile Ky I garbage this so I am going collage with JCTC that the of the collage thank you my friends
salma
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
if A not equal to 0 and order of A is n prove that adj (adj A = A
rolling four fair dice and getting an even number an all four dice
Differences Between Laspeyres and Paasche Indices
No. 7x 4y is simplified from 4x + (3y + 3x) 7y
how do you translate this in Algebraic Expressions
Need to simplify the expresin. 3/7 (x+y)1/7 (x1)=
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
what's the easiest and fastest way to the synthesize AgNP?
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials and their applications of sensors.
what is system testing?
AMJAD
preparation of nanomaterial
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field .
1Electronicsmanufacturad IC ,RAM,MRAM,solar panel etc
2Helth and MedicalNanomedicine,Drug Dilivery for cancer treatment etc
3 Atomobile MEMS, Coating on car etc.
and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change .
maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^15
Prasenjit
can nanotechnology change the direction of the face of the world
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
how did you get the value of 2000N.What calculations are needed to arrive at it
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What makes metals better to use as wires than nonmetals? (please link to bonding type)??? HELP
Source:
OpenStax, Chemistry grade 10 [caps]. OpenStax CNX. Jun 13, 2011 Download for free at http://cnx.org/content/col11303/1.4
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