Chemical Reaction

The chemical reaction campaign has come to an end now that the new European Chemicals law, REACH, has come into force.

However, now the law is in place there is much to be done to ensure that it really does protect us from the worst chemicals; the following web sites can tell you more about what is happening now.

New pan-European Chemicals legislation - REACH


Read a presentation about the implementation of REACH here

Following an almost nine year long discussion on the European Chemicals policy reform, the new law, REACH, was finally approved on 18 December 2006. REACH, which stands for Registration, Evaluation and Authorisation of Chemicals, is a first modest step by the European Union towards a new approach to chemicals management. It� promises to put an end to public ignorance about the health and environmental effects of chemicals, many of them incorporated in everyday products, and phase out the most hazardous chemicals from the market if safer alternatives are available (the substitution principle).

Under REACH, companies will have to provide safety data for large volume chemicals that they produce or import into Europe, while the use of most dangerous ones (such as the ones causing cancer, infertilities or that persist in our bodies or the environment) will have to be authorized by the European Commission.

REACH will cover 30,000 of the 100,000 chemicals available on the EU market and came into force in June 2007. As a regulation, it will have direct effect in all 27 member states as well as on chemicals and articled imported into the EU.

Unfortunately, REACH also contains many loopholes which will still allow many hazardous chemicals to continue being used in manufacturing and consumer goods. Additional concessions exempt companies which import and manufacture chemicals in volumes below 10 tonnes a year - 60% of chemicals covered by REACH - from the requirement to provide any meaningful safety data. Moreover, many decisions have been postponed to the implementation and future revisions of the law. See timeline

Will REACH deliver?
The loopholes and provisions for self-regulation contained in the law leave REACH very vulnerable to further manipulation by the chemical industry. There remains plenty of room for the chemical industry to manoeuvre around the loopholes to keep hazardous substances on the market, even if safer alternatives exist. The new EU Chemicals Agency in Helsinki will have to be closely monitored to ensure that REACH can deliver. Without the necessary support, hazardous chemicals will continue to contaminate wildlife, our homes and our bodies, and REACH will prove a failure.

This is why in the future we will need to keep careful watch over how the law is put into practice and to ensure that it delivers promised benefits to human health and environment. We will keep informing you on how you can press for change and use REACH to ensure better protection from toxic chemicals for you, your family and your environment.

Why we need safer chemicals


Pretty much anything you buy - whether it's soap or a computer, perfume or paints - will contain a mixture of substances produced in a chemical factory. Chemicals are used for all kinds of reasons such as to smell nice or to kill germs.
The uncomfortable truth is, more and more research is suggesting that some chemicals are threatening our health with a new kind of pollution that contaminates the bodies of us and our families

CHEMICAL OXYGEN DEMAND (COD)

Dichromate Reflux Technique Standard Method.


Equipment Required

  1. 500-millilitre (ml) Erlenmeyer flask with standard (24/40) tapered glass joints
  2. Friedrichs reflux condensers (12-inch) with standard (24/40) tapered glass joints
  3. Electric hot plate or six-unit heating shelf
  4. Volumetric pipettes (10, 25, and 50ml capacity)
  5. Burette, 50 ml - 0.1 ml accuracy
  6. Burette stand and clamp
  7. Analytical balance, accuracy 0.001gram (g)
  8. Spatula
  9. Volumetric flasks (1,000ml capacity)
  10. Boiling beads, glass
  11. Magnetic stirrer and stirring bars

Chemicals Required

  1. Potassium dichromate (K2Cr2O7) 0.25N
  2. Sulphuric acid (H2SO4) / silver sulphate (Ag2SO4) solution
  3. Mercuric sulphate (HgSO4) crystals
  4. Ferrous ammonium sulphate (FAS) [Fe(NH4)2(SO4)2], approximately 0.01N
  5. Ferroin indicator (1, 10-phenanthroline and ferrous ammonium sulphate)

Caution: In carrying out the following procedures, use proper safety measures, including protective clothing, eye protection, and a fume hood. Reagents containing heavy metals (HgSO4 and Ag2SO4) should be disposed of as toxic wastes.

Chemical Preparation

  1. Dissolve 12.259g of oven-dried (primary standard grade dried at 103oC to a constant weight) potassium dichromate in distilled water and dilute to 1 litre volume in a volumetric flask.
  2. Add 22g of reagent grade silver sulphate to a 4kg bottle of concentrated sulphuric acid (H2SO4) and mix until the silver sulphate goes into solution.
  3. Use 1 g of mercuric sulphate (HgSO4) to complex 100 mg chloride (2,000 mg/l).
  4. Dissolve 1.485g of 1,10-phenanthroline monohydrate and 0.695g of ferrous ammonium sulphate heptahydrate in distilled water and dilute to approximately 100ml. (Alternatively, this indicator may be purchased as Ferroin Indicator from most scientific suppliers.)
  5. Dissolve 39g reagent grade ferrous ammonium sulphate hexahydrate in distilled water. Add 20ml of concentrated sulphuric acid (H2SO4). Cool and dilute to exactly 1 litre in a volumetric flask using distilled water. The ferrous ammonium sulfate (FAS) titrant must be standardized daily by the following procedure:

    Dilute 10ml of standard potassium dichromate (K2Cr2O7) solution to 100ml with distilled water. Slowly add 30ml of concentrated sulphuric acid and cool to room temperature. Titrate with ferrous ammonium sulphate titrant, using 2 to 3 drops (0.10 to 0.15 ml) of Ferroin indicator.

    Normality of FAS = (ml K2Cr2O7)(0.25)
    ml FAS required

    The deterioration of FAS can be decreased if it is stored in a dark bottle.

Procedure

  1. Place a 50ml sample or an aliquot diluted to 50ml in a 500ml refluxing flask. The blank is prepared using 50ml of distilled water. This is a precise measurement and a 50ml volumetric pipette should be used. Refer to COD Range
  2. Add 5 to 7 glass boiling beads.
  3. Add 1g of mercuric sulphate (HgSO4), 5ml of concentrated sulphuric acid / silver sulphate solution, and mix until the HgSO4 is in solution. The function of the mercuric sulphate is to bind or complex chlorides. One gram may not be required if the chloride concentration is low. (Caution: Always add acid slowly down the side of the flask while mixing to avoid overheating. It may be necessary to use gloves because of the heat generated.)
  4. Accurately add 25ml of 0.25 N potassium dichromate (K2Cr2O7) and mix.
  5. Add while mixing, an additional 70ml of concentrated sulphuric acid-silver sulphate solution.
  6. After thorough mixing, attach the flask to the reflux condenser, apply heat, and reflux for 2 hours. Refluxing time can be decreased depending on the ease of oxidation of organic materials. This time may be determined by refluxing for periods from 15 minutes to 2 hours and comparing the results.
  7. A reagent blank containing 50ml of distilled water treated with the same reagent as the sample should be refluxed with each set of samples.
  8. Cool the apparatus to room temperature after the refluxing period. Wash down the interior of the condenser and flask twice with approximately 25ml portions of distilled water.
  9. Remove flask from the condenser and dilute to a final volume of approximately 350ml with distilled water.
  10. Add 4 to 5 drops of Ferroin indicator and a magnetic stirring bar.
  11. Place flask on a magnetic stirrer and rapidly titrate with 0.1 N ferrous ammonium sulphate to the first red-brown endpoint.

    Caution: Use care in titration. The endpoint is very sharp and may be reached rapidly.

    Formula to determine COD:

    COD (mg/l) = (a-b)(N) x 8,000 / sample size (ml)

    Where:

    a = ml Fe(NH4)2(SO4)2 used for blank

    b = ml Fe(NH4)2(SO4)2 used for sample

    N = normality of FAS titrant (Fe(NH4)2(SO4)2)

    ml sample = the actual volume of sample used before dilution

    Sources of Error

    COD Range and Sample Size

    COD Range (mg/l) 50-800 100-1500 240-3700 480-7500 1200-18800 2400-3700 40000-375000
    Volume of Sample (ml) 50 25 10 5 2 1 0.1

    All samples high in solids should be blended for 2 minutes at high speed and stirred when an aliquot is taken. Sample volumes less than 25ml should not be pipetted directly, but serially diluted and then a portion of the diluent removed:

    Elimination of Interference

    One gram of mercuric sulphate (HgSO4) will complex 100mg of chloride in a 50ml sample (2,000 mg/l). For samples higher in chloride more HgSO4 should be used in the ratio of 10:1 HgSO4.

    Interference from nitrites can be prevented by the addition of 10:1 ratio of sulfamic acid:nitrite. The addition of the silver sulphate (AgSO4) concentrated sulphuric acid (H2SO4) refluxing acid will aid in the oxidation of some organic nitrogen compounds, but aromatic hydrocarbons and pyridine are not oxidized to any appreciable amount.

SOURCE;oasisenviro.co.uk/chemical_oxygen_demand

To react or not to react? THAT is the question!

To visualize a synthesis reaction look at the cartoon
Chemical changes are a result of chemical reactions. All chemical reactions involve a change in substances and a change in energy. Neither matter or energy is created or destroyed in a chemical reaction---only changed. There are so many chemical reactions that it is helpful to classify them into 4 general types which include the following: SYNTHESIS REACTION
In a synthesis reaction two or more simple substances combine to form a more complex substance. Two or more reactants yielding one product is another way to identify a synthesis reaction.
For example, simple hydrogen gas combined with simple oxygen gas can produce a more complex substance-----water!
The chemical equation for this synthesis reaction looks like:
synthesisimage
reactant + reactant -------> product
SOURCE;usoe.k12.ut.us/CURR/Science/sciber00/8th/matter/sciber/chemtype

Harmful Chemicals In Cigarettes & Tobacco Smoke

Cigarettes are one of few products which can be sold legally which can harm and even kill you over time if used as intended.

Currently there are ongoing lawsuits in the USA which aim to hold tobacco companies responsible for the effects of smoking on the health of long term smokers.

Benzene (petrol additive)
A colourless cyclic hydrocarbon obtained from coal and petroleum, used as a solvent in fuel and in chemical manufacture - and contained in cigarette smoke. It is a known carcinogen and is associated with leukaemia.

Formaldehyde (embalming fluid)
A colourless liquid, highly poisonous, used to preserve dead bodies - also found in cigarette smoke. Known to cause cancer, respiratory, skin and gastrointestinal problems.

Ammonia (toilet cleaner)
Used as a flavouring, frees nicotine from tobacco turning it into a gas, found in dry cleaning fluids.

Acetone (nail polish remover)
Fragrant volatile liquid ketone, used as a solvent, for example, nail polish remover - found in cigarette smoke.

Tar
Particulate matter drawn into lungs when you inhale on a lighted cigarette. Once inhaled, smoke condenses and about 70 per cent of the tar in the smoke is deposited in the smoker's lungs.

Nicotine (insecticide/addictive drug)
One of the most addictive substances known to man, a powerful and fast-acting medical and non-medical poison. This is the chemical which causes addiction.

Carbon Monoxide (CO) (car exhaust fumes)
An odourless, tasteless and poisonous gas, rapidly fatal in large amounts - it's the same gas that comes out of car exhausts and is the main gas in cigarette smoke, formed when the cigarette is lit. Others you may recognize are :

Arsenic (rat poison), Hydrogen Cyanide (gas chamber poison)

source: Health Education Authority (UK) - Lifesaver

SOURCE;quit-smoking-stop.com/harmful-chemicals-in-cigarettes



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