Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has a great affinity towards oxygen, and forms a protective layer of oxide on the surface when exposed to air. Aluminium visually resembles silver, both in its color and in its great ability to reflect light. It is soft, non-magnetic and ductile. It has one stable isotope, 27Al; this isotope is very common, making aluminium the twelfth most common element in the Universe. The radioactivity of 26Al is used in radiodating.
Chemically, aluminium is a weak metal in the boron group; as it is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and highly charged; as such, it is polarizing, and bonds aluminium forms tend towards covalency. The strong affinity towards oxygen leads to aluminium's common association with oxygen in nature in the form of oxides; for this reason, aluminium is found on Earth primarily in rocks in the crust, where it is the third most abundant element after oxygen and silicon, rather than in the mantle, and virtually never as the free metal.
The discovery of aluminium was announced in 1825 by Danish physicist Hans Christian Ørsted. The first industrial production of aluminium was initiated by French chemist Henri Étienne Sainte-Claire Deville in 1856. Aluminium became much more available to the public with the Hall–Héroult process developed independently by French engineer Paul Héroult and American engineer Charles Martin Hall in 1886, and the mass production of aluminium led to its extensive use in industry and everyday life. In World Wars I and II, aluminium was a crucial strategic resource for aviation. In 1954, aluminium became the most produced non-ferrous metal, surpassing copper. In the 21st century, most aluminium was consumed in transportation, engineering, construction, and packaging in the United States, Western Europe, and Japan.
Despite its prevalence in the environment, no living organism is known to use aluminium salts metabolically, but aluminium is well tolerated by plants and animals. Because of the abundance of these salts, the potential for a biological role for them is of continuing interest, and studies continue.
Homework Statement
Aluminium atoms at 1173K enter a vacuum chamber. Calculate the most probable speed for the atoms.
Homework Equations
vmp=\sqrt{}(2kT/m)
The Attempt at a Solution
The molar mass of aluminium is 0.0270kg mol^-1, so
vmp=\sqrt{}(2*1.381*10^-23JK^-1)*1173K/0.0270kg...
Homework Statement
An aluminium block of m is hung from a steel wire of length L. The fundamental
frequency for transverse standing waves on the wire is 300 Hz. The block
is then immersed in water so that half of its volume is submerged. What is the
new fundamental frequency? (You may assume...
Hello,
Does anybody know whether the alloy elements (Cr, Mg, Mn, Fe) in the aluminium alloy Al - 5083 are mainly interstitial or substitutional. The reason I want to know this is that this has an effect on the thermal neutron diffraction of this material...
thanks!
Homework Statement
Hi there if you have an aluminium alloy with an uts of 400MPa and is tested to a ratio of 0.1 and the endurance limit is 10^7 cycles is 160MPA what is the mean stress with a stress amplitude of 160MPa, how do i work out the max and min stresses and using the Goodman...
hey guys, just a quick question about the magnetic field lines and aluminium,
because aluminium is not magnetic, do magnetic field lines pass through the metal unhindered, or are they distorted? or is thickness become an issue?
this is in relation to mounting permenant magnets in an...
Good Day,
I have defective Aluminium windings motor.
As you know Aluminium is very difficult to winding.
So, I want to use Copper wire to re-winding the motor.
How can I do that?
What size should I use and what will be the number of turns?
Someone told me that you can use...
Can anyone help me with this homework question? it was like this:
The reaction between the acid and aluminium is slow in the beginning and then gets faster. Give an explanation for this observation.
Thanks.
Homework Statement
An aluminium sleeve of internal diameter 4.000cm at 10 degrees Celsius is heated and slipped over a steel rod of diameter 4.040cm (at 10 degrees Celsius. When the aluminium sleeve and steel rod return to room temp they are impossible to separate. Assume that the...
Hello, this is my first post, i hope somebody can help me.
I have searched for the answer myself all over on the web and here, but I am stuck.
Im trying to work out the maximum pressure (psi) that i can get into an aluminium cylinder that's 80mm wide and 250mm tall and 4mm thick
ive found...
Homework Statement
Question: If the linear expansivity of aluminium is 24 x 10-6 K-1, how much does the aluminium expand during the heating?
Homework Equations
As far as additional information on the question goes;
An aluminium rod is heated from 15 degrees Celsius to 120 degrees Celsius. The...
Could anyone please help me?
If I have a piece of aluminium Angle that is 30mm x 30mm by 3mm thick and 1m long, if I were to substitue this with a piece that is the same thickness and length but 60mm x 60mm what increase in strength would I see?
If instead of increasing the size what would...
Hi Guys
This is my first post. I hope someone can help. I'm building a hovercraft, the fan that lifts the hovercraft is made of pine timber and the blades are carved from the pine. The blades weigh 200grams each and are spinning at 3000rpm. Question, if a blade broke of wilst spinning at...
Discuss in terms of the possible microstructural differences how the proof
stress of the aluminium alloy tested in bending could be greater than the proof stress of the alloy
tested in the tensile machine. (Be specific to aluminium alloys)
Hallo
Is there someone that can explain why Al can be used to form Ohmic contats to both p- and n-type Si?
When looking at a Ohmic junction between a metal and a semiconductor, it is formed when the work functions are as follows: \Phi_m>\Phi_p and \Phi_m<\Phi_n. How can Al fulfil both or...
Hi PF,
I watched a video on youtube about a physics professor who asked some questions at the end of the video but didn't answer them. One really interested me.
If you have a plane aluminum plate with a very little hole say in its center and you heat the whole plate. What happens to the size...
I am made to understand that you are meant to use different etching agents for different aluminum alloys. How does one find which etching agent is the right one for each alloy?
Does anyone know what etching agent I can use for Al 3104?
Thank you
Hi everyone,
Not sure if this should be here or in the chemistry section. It's a question about chemical reactions in aluminium.
I work for a construction company and we have a number of aluminium sheets used for cladding and roofing. We've noticed that some of these have a blacking and...
Hi all, I am after some materials based help please.
Im trying to re-profile part of an intake runner on an aluminium cylinder head. Wanting longevity, I've opted against the usual route of using epoxy resin to build up a specific area.
Basically i would like to try and fill the section (or...
Does anyone know firstly what this type of formula is called: H-H, i know that it describes the bonding but can't remember what it is called :O
Secondly, how would i show the bonding in aluminium oxide usingthis type of formula?
Hi guys
I was looking at a website and the engineer was working with Gallium and Allaminium oxide, and by accident they put water with it and the reaction produced hydrogen.
Could anyone expand on this?
regards
Bioman
Question What colour would molten aluminium be if its daylight at 1000 degrees
the reason is wether this is true or not
''The approximate temperature of a hot metal is given by its color, quite independent of the composition of the metal. (A notable exception is aluminum, which due to...
Homework Statement
A 40mm diameter bar of aluminium is 2.5m long the bar is has its temperature raised from 20°c to 40°c. Determine the increase in length of the bar in mm. Take the Al = 24 × 10-6 °C-1
How much heat has been transferred into the bar if the SCH = 0.9kj/kg °C
Homework...
[SOLVED] Aluminium Hydroxide as Amphoteric Substance
Homework Statement
Aluminium hydroxide is an amphoteric substance. It can act as either a Bronsted-Lowry base or a Lewis acid. Write a reaction showing Al(OH)_{3} acting as a base toward H^{+} and as an acid toward OH^{-}.
Homework...
i was doing an experiment with liquid nitrogen, i had to put an aluminium body initially at room temperature inside a glass with the nitrogen at 77K, first it starts making a loud noise then a lower noise that is slowly increasing and finally near the equilibrium point the noise gets strangley...
Homework Statement
A clear plastic pen of length 14.5 cm is rubbed with wool. The charged plastic pen is held over a small uncharged disk shaped piece of aluminium foil of diameter 0.5cm. How close you must move the pen to the foil in order to pick up the foil?
The Attempt at a...
I desperatly need help, i need to know everything there is to know about the recovery of aluminium from bauxite ore, the process, the cost, everything.
Please, if you have any knowledge or know of any GOOD webpages, please post them here.
thanks:)
Hi guys,
Not sure whether this belongs in elec or mats/chem so I thought I'd put it here.
Basically I am trying to extract current from a thin aluminium layer.
Due to the Al-Oxide layer, simply soldering an external lead isn't working.
I'm able to etch away (some?) of the oxide layer...
Quick question (...and I hope I have this in the right forum)
Does anybody know anything about the effects of inhaling dust particles of anodized aluminium?
I am especially interested about finding information on any possible negative effects on the respratory and cardiovascular systems...
Hi all,
I am currently in the process of writing up my AS coursework investigation of finding the specific heat capacity of Aluminium, and am a bit stuck at explaining some of my results.
My results for the SHC of Aluminium are lower than the published values.
My value: 700.93 JKgC...
Hi all,
Am having a bit of trouble with the chemistry behind 3 tests on aluminium.
The first i think is straight forward. Adding an aluminium water mix to some ammonium hydroxide and then warming. I think this gives me ammonia gas is this true?
Then the second is with the same mix of...
aluminium framework...
I am designing an aluminium frame bed. I have desided to use aluminium extrusion either square or rectangular shape to form the main 4 bars at the base supported by 4 legs. I will use panels of plywood at the centre holding the mattress.
My question is...suppose the...
In a paragraph in the textbook "When CSIRO scientists were called into investigate, they discovered that the cause was the oxidation of iron pyrites in these area, much of which had been exposed as a result of draining swamps for grazing cattle and the use of floodgates to drain cane fields...
Hi. I am new here! I'm doing a experiment on the absorption of beta radiation of aluminium and I need help! :redface: Does anyone know what the absorption coefficient of aluminium? Or at least where I can find it. Thanks in advance! o:)
P.S. Sorry if I've posted in the wrong part of the forum...
1' after a metal rod rubbing with a cloth, is the metal rod remains neutral in charge whereas the cloth will be positive charge?
2' a small pieces of paper and aluminium foil are attracted by charged metal rods when the rods are brought close to them. however, the former stick to the rod...
hi!
i am trying to find out information on what happens to 2024 alu when it is heated and then quenched rapidly. i am trying to find information relating to grain boundary segregation as the rate of cooling is changed. does anybody have the knowledge of a good source?
thanks guys
Is there a way to measure the temperature in an induction oven for melting of aluminium(700 C). The pyrometer I’m using can’t correctly display the temperature when the system is running because it interferes with the induction field. The non-contact IR-camera has been abandoned because of the...
Hi,
I have been doing some experimentation with parallel plate capacitors, see https://www.physicsforums.com/showthread.php?t=124150"
For one arrangement of aluminium plates (air as the dielectric) I was expecting the measured capacitance to be approx. 7.9pF and what I measured was 65pF...
I've calculates the density of aluminium using the debye theory.
I found The atom density n = 2.24E28 m^-3 at 600k (assumed to be the same as at room temperature).
Therefore the density is just the molecular mass m (m(grams) = (79amu / Avogadros number), multiplied by the atom density...
Hey,
I'm doing some coursework on the properties of aluminium and why aluminium is a good material for computer cases.
Now, in the coursework I must have a section on some sort of calculation but am clueless as to what calculation I could do (i.e. if you was doing nylon for a fishling line...
hi all,
im wondering why it is dangerous to grind a mixture of powdered aluminium with potassium chlorate in a mortar and pestle.
any help would be great.
This question comes from my Grade 11 Univ. Physics Teacher.
Problem: To as many significant figures as you can justify, determine the thickness of the aluminium foil.
1. Purpose
2. Procedure
3. Calculations (Significant Figures)
4. Conclucion
Now I know that the density of...