Hsc Marathon 2009 - Chemistry (5 Viewers)

[gurmies]

Kaatie is correct.

A substitution reaction is a reaction that occurs with SATURATED hydrocarbons or "alkanes", where Hydrogen atoms are replaced with other atoms or radicals, e.g.

CH4(g) + Cl2(g) --------> CH3Cl(g?) + HCl(g?)

In order for this reaction to occur, ultraviolet light needs to be present, and even then, the reaction is quite slow.

What is addition polymerisation?

 

[scora]

the process of small alkene monomer units combining with other momomer units via the breaking of the double bond to form a long chain molecule

q- is addition polymerisation only for alkenes?

 

[jackc91]

q- is addition polymerisation only for alkenes?

No. Alkynes can also undergo addition polymerisation since they are unsaturated.

QUESTION
Name a radioisotope and outline its use in either medicine/industry

 

[study-freak]

QUESTION
Name a radioisotope and outline its use in either medicine/industry

Strontium-90 is used in thinkness gauges in industries to monitor the thinkness of things such as plastic film, metal sheets, papers, aluminium foil etc to ensure that the correct thinkness is maintained.


Q: What are the impacts of oxides of nitrogen on the environment and health?

 

[Kaatie]

sulfur dioxide- can irritate eyes and the respiratory tract, can cause lung damage and asthma and is a major component of smog
nitrogen- can harm the respiratory system and damage the lungs allowing infections to occur. Asthma can be triggered by people who are sensitive to these gases, part of photochemical smog. also contributes to greenhouse gases.

identify starch, glucose, ethene and polyethene as monomers or polymers

 

[Timothy.Siu]

identify starch, glucose, ethene and polyethene as monomers or polymers

hi katie, u a hannah montana fan ?

anyways

glucose is a monomer, starch is polymer made up of alpha glucose (?) and ethene is a monomer and polyethene is a polymer!!
is that all i'm supposed to say.

Name one biopolymer and describe its recent devolopment and uses.

 

[shady145]

sulfur dioxide- can irritate eyes and the respiratory tract, can cause lung damage and asthma and is a major component of smog
nitrogen- can harm the respiratory system and damage the lungs allowing infections to occur. Asthma can be triggered by people who are sensitive to these gases, part of photochemical smog. also contributes to greenhouse gases.

forgot to mention acid rain,

 

[Kaatie]

hi katie, u a hannah montana fan ?

anyways

glucose is a monomer, starch is polymer made up of alpha glucose (?) and ethene is a monomer and polyethene is a polymer!!
is that all i'm supposed to say.

Name one biopolymer and describe its recent devolopment and uses.

You bet i am

 

[shady145]

Name one biopolymer and describe its recent devolopment and uses.

biopol
used in medicine, shampoo bottles and other items of such.
it has been increasingly used as it is biodegradable, and can be used as a substitute for polyethelyene products

 

[shady145]

umm
Q. account for changes in the oxidation state of species in terms of their loss or gain of electrons.

 

[Kaatie]

biopol, it is produced industrially by bacteria growing in tanks with a carbon-based food source. The polymer is then isolated and purified. Recently attempts to produce the polymer have used genetic engineering. Advantages of this are faster growth, better yields, easier recovery and production of less extra waste biomass. Uses include carrier for slow release of insecticides, herbicides, or fertilizers, disposable containers for shampoo and cosmetics disposable items and fast food utensils.

What are 10 chemicals presently produced by the petrochemical industry

 

[Kaatie]

oxidation states give an indication of electron transfer in redox reactions with oxidation being an increase in oxidation state and reduction a decrease in oxidation state. my question is above

 

[Kaatie]

oh and while im here does anyone know how i can get chem contexts 2 answers or the cd, can you download it somewhere etc?

 

[Timothy.Siu]

oh and while im here does anyone know how i can get chem contexts 2 answers or the cd, can you download it somewhere etc?

without buying it?
no idea.

 

[shady145]

What are 10 chemicals presently produced by the petrochemical industry

-hexane
-cyclohexane
-benzene
-2,2,4-trimethylpentane
-1,4-dimethylcyclohexane
-toluene
-ethene (ethylene)
-propane
-butane
-octane

Q. describe the dehydration of ethylene, and identify the need for the catlayst in this process and the catalyst used.

 

[bored of sc]

just out of curiosity, how come whenever i quote someone, their name doesn't show up

Make sure in the first bracket is says [ quote=name] and the second bit has [ /quote] without the gaps of course.

 

[gurmies]

shady145, you either mean the dehydration of ethanol or the hydration of ethylene. I'll describe both then:

Ethylene can be prepared by dehydrating ethanol. The purpose of the concentrated sulfuric acid catalyst is to not only act as a catalyst, but to also act a dehydrating agent, removing water from ethanol during the reaction:

CH3CH2OH <----------> CH2CH2 + H2O

Ethanol can be prepared by hydrating ethylene at high pressures using dilute phosphoric acid as a catalyst...maybe it's a hydrating agent, I wouldn't know...

CH2CH2 + H20 <----------> CH3CH2OH

List 3 advantages and 3 disadvantages of ethanol as an alternative fuel

 

[shady145]

shady145, you either mean the dehydration of ethanol or the hydration of ethylene. I'll describe both then:

lol yea i meant ethanol, not ethylene.

 

[shady145]

List 3 advantages and 3 disadvantages of ethanol as an alternative fuel

advantages
1. it is a renewable energy source
2. it is readily available
3. the amount of CO2 released during combustion is equal to the CO2 taken in by the plant used to produce it.

disadvantages
1.large land areas are required wiping out forests to make room
2.crops will be used for ethenol other than food
3.fuel lines will have to be modified if we are to use a higher percentage ethanol.

Q. summarise the process involved when producing ethanol from sugar cane

 

[Timothy.Siu]

Q. summarise the process involved when producing ethanol from sugar cane

u get like molasses or something and the sugar stuff like sucrose from sugar cane and then enzymes convert this to glucose/fructose and some other enzymes ferment this into ethanol lol

Q. Why are some batteries not rechargeable?