Grahams Formula for Diffusion and Effusion

Graham's Formula for Diffusion and Effusion Grahams law expresses the relationship between the rate of effusion or diffusion of a gas and the gass molar mass. Diffusion describes the spreading of a gas throughout a volume or a second gas, while effusion describes the movement of a gas through a tiny hole into an open chamber. In 1829, Scottish chemist Thomas Graham determined, through experimentation, that the rate of effusion of a gas is inversely proportional to the square root of the gas particle mass and to its density. In 1848, he showed that the rate of effusion of a gas is also inversely proportional to the square root of the molar mass of the gas. Grahams law also shows that the kinetic energies of gases are equal at the same temperature. Grahams Law Formula Grahams law states that the rate of diffusion or effusion of a gas is inversely proportional to the square root of the molar mass of the gas: r ∠ 1/(M) ½ or r(M) ½ constant ï » ¿where r rate of diffusion or effusion and M molar mass. Generally, this law is used to compare the difference in rates between between two different gases: Gas A and Gas B.  The law assumes that the temperature and pressure are the same for the  two gases.  When Grahams law is used for such a comparison, the formula is written: rGas A/rGas B (MGas B) ½/(MGas A) ½ Example Problems One way to apply Grahams law is to determine whether one gas will effuse more quickly or slowly than another and to quantify the difference in rate. For example, if you want to compare the rates of effusion of hydrogen gas (H2) and oxygen gas (O2), you use the molar masses of the gases (two for hydrogen and 32 for oxygen) and relate them inversely: rate H2/rate O2 321/2 / 21/2 161/2 / 11/2 4/1 The equation shows that hydrogen gas molecules effuse four times more quickly than oxygen molecules. Another type of Grahams law problem may ask you to find the molecular weight of a gas if you know the identity of one gas and the ratio between the rates of effusion of two different gases. This problem can be expressed as: M2 M1Rate12 / Rate22 A practical application of Grahams law is uranium enrichment. Natural uranium consists of a mixture of isotopes, each of which has a slightly different mass. In gaseous diffusion, uranium ore is made into uranium hexafluoride gas, which is repeatedly diffused through a porous substance. Each time, the material that passes through the pores becomes more concentrated in U-235 (the isotope used to generate nuclear energy). This is because the isotope diffuses at a faster rate than U-238, which is heavier.

Design market research report Essay Example | Topics and Well Written Essays - 1000 words

Design market research report - Essay Example In his early projects he used recycled bottles. He has sought to instill his products with a magic and romance that usually transcend their functions. He makes computer generated floral drawings and also develops designs for mass production. He has a work collection of glassware for Dartington crystal and also develops new products e.g. eyewear (Jennifer 2006). He has created a collection of products in different areas i.e. tableware, party and decoration items, consumables and lighting. He has also collaborated with Target which is a large retail store in the making of different products. He has made store decorations for one thousand five hundred stores, graphics for all catalogues and has also collaborated with directors of arts in television commercials. They sell their products in Target. He prefers this Target in comparison to others because it has a larger potential and scale. It is estimated that over one hundred million people shopping in Target usually come across his products especially during the Christmas festivities (Jennifer 2006). His project the Wednesday light which is used by Habitat has also enlarged his market. This is because working with Habitat has made the lights to be produced in large quantities. The production in mass quantities has also enabled him to keep the prices down. He employs modern techniques in his designs. ... He uses technology as a way of creating new methods and also to make new expressions. He likes the use of sensual material surfaces. It's the new industrial processes that make him be in a position to look at the quality again. He uses the computer to draw then sends the materials directly to the production machines to make the products. He has more preference on the process of manufacturing. Currently he has designed a new version of Wednesday night which is made of nickel plated brass instead of the former stainless steel. It is of a larger size which in turn means that a large variety of flower designs would fit. The modern version also has less punk because it is packed in a flat pack. He has also developed romantic aesthetics which depict nature. These aesthetics have vibrant colors. He makes doll chairs and other chairs which are usually covered with organdies and mouse lines and are prepared using s variation of colors and textures. He makes designs with colors which are usually inspired by nature. Marrimeko Company Marrimeko is a finish company that was established in 1951. The company is involved in the manufacturing, designing, and also markets high quality clothing, bags, and other accessories. The company designs products of vivid colors and which have large scale patterns. This has made it to increase its popularity and also increase its market level. They have bold patterns and unique styles which cut across generations. The company usually works in a different way as compared to other companies. It has processes that are not so linear and coherent. Issues are usually heavily discussed and a lot of thinking is done before any decision is made in this company. Marrimeko has a high level market. Their sales had a 50% rise within the last two years.