Rates of Reactions :: GCSE Chemistry Coursework Investigation

Rates of Reactions Aim: I am going to investigate how the rate of the reaction between sodium thiosulphate and hydrochloric acid depends on the concentration of sodium thiosulphate. The reaction rate of a chemical reaction is the speed of production of products from reactants. Sodium thiosulphate + hydrochloric acid ==> sodium chloride + sulphur dioxide + water + sulphur Na2S2O3 (aq) + 2HCl (aq) ==> 2NaCl (aq) + SO2 (aq) + H2O (l) + S(s) The solid sulphur (S(s)) formed in this reaction makes the colourless solution go cloudy. Factors: The factors I believe that will affect what happens in the investigation are: * Catalyst- A catalyst s a substance which alters the rate of a chemical reaction but is chemically unchanged at the end of the reaction. - A catalyst speeds up a reaction; an inhibitor (a substance) slows it down. * Concentration- The more concentrated the faster the rate (note in some cases the rate may be unaffected by the concentration of a particular reactant provided it is present at a minimum concentration). Remember for gasses, increasing the pressure simply increases the concentration so that's the same thing. * Surface area- greater surface area and since the reaction occurs at the surface we get a faster rate. * Temperature- Usually reactions speed up with increasing temperature ("100C rise doubles rate"). The collision theory: Particles need to collide with each other to react and the collision theory is all about this. The can be affected by the temperature of the particles, the concentration of the particles, whether a catalyst is used or the surface area (if the particles are solid). Temperature affects the rate of a reaction because if particles are cold, they move slowly and there are few collisions between them. But when they are heated up they move much faster or you can also say they have more kinetic energy. When the move faster there is more of a chance of a collision. More collisions means that the reaction goes faster - its rate increases. Concentration of the acid used also affects the rate because when there is a higher concentration (more acid) there are more particles to collide with each other-more collisions means that the reaction goes faster. A catalyst is a substance that can speed up a chemical reaction without actually being used up in the reaction. It gives the particles a surface to stick to so they can collide with each other there - more collisions. Again when there are more collisions this causes the reaction to go faster. Surface area also affects the rate of a reaction if the particles are

Disability and Individual Disabled Person

* Explain the potential impact of disability on the outcomes and life chances of children and young people (CYP 3. 7 3. 1) The potential impact of disability on the outcomes and life chances of children and young people are that they get physical impairments and chronic medical conditions may compromise healthy development and disrupt their educational experiences. Adper children’s all round development, move on further into the future to have financial difficulties and restricted opportunities and career paths.All of these outcomes can destabilize families and relationships causing stress and depression. * The importance of positive attitudes towards disability and specific requirements helps a person with additional needs to feel more valued and equal to every other child or young person, it also prevents isolation of a child. A positive attitude ensures inclusive and tting. It builds positive relationships so that everyone in the setting and in the world feels respected, sa fe and happy where they live, and spend their time. Explain the social and medical models of disability and the impact of each on practice (CYP3. 7 3. 3) The medical model promotes the view of a disabled person as dependent and needing to be cured or cared for, and it justifies the way in which disabled people have been systematically excluded from society. The disabled person is the problem, not society. Control resides firmly with professionals; choices for the individual are limited to the options provided and approved by the ‘helping' expert.The medical model is sometimes known as the ‘individual model’ because it promotes the notion that it is the individual disabled person who must adapt to the way in which society is constructed and organised. By labelling a child because of their disability can prevent us from seeing the child as a whole person like their gender, culture and social background the medical models is a traditional view of disability and that through medical intervention the person can be cured where in fact in ost cases there is no cure. They expect disabled people to change to fit into society. * Explain the different types of support that are available for disabled children and young people and those with specific requirements (CYP3. 7 3. 4) Specialised services  Ã¢â‚¬â€œ in my setting we have a special educational needs coordinator and we use other services such as physio therapist, speech therapists, school nurse, social services we use these services in order to provide the right care for the children in need.

Introduction to Holography

If youre carrying money, a drivers license, or credit cards, youre carrying around holograms. The dove hologram on a Visa card may be the most familiar. The rainbow-colored bird changes colors and appears to move as you tilt the card. Unlike a bird in a traditional photograph, a holographic bird is a three-dimensional image. Holograms are formed by interference of light beams from a laser. How Lasers Make Holograms Holograms are made using lasers because laser light is coherent. What this means is that all of the photons of laser light have exactly the same frequency and phase difference. Splitting a laser beam produces two beams that are the same color as each other (monochromatic). In contrast, regular white light consists of many different frequencies of light. When white light is diffracted, the frequencies split to form a rainbow of colors. In conventional photography, the light reflected off an object strikes a strip of film that contains a chemical (i.e., silver bromide) that reacts to light. This produces a two-dimensional representation of the subject. A hologram forms a three-dimensional image because light interference patterns are recorded, not just reflected light. To make this happen, a laser beam is split into two beams that pass through lenses to expand them. One beam (the reference beam) is directed onto high-contrast film. The other beam is aimed at the object (the object beam). Light from the object beam gets scattered by the holograms subject. Some of this scattered light goes toward the photographic film. The scattered light from the object beam is out of phase with the reference beam, so when the two beams interact they form an interference pattern. The interference pattern recorded by the film encodes a three-dimensional pattern because the distance from any point on the object affects the phase of the scattered light. However, there is a limit to how three-dimensional a hologram can appear. This is because the object beam only hits its target from a single direction. In other words, the hologram only displays the perspective from the object beams point of view. So, while a hologram changes depending on the viewing angle, you cant see behind the object. Viewing a Hologram A hologram image is an interference pattern that looks like random noise unless viewed under the right lighting. The magic happens when a holographic plate is illuminated with the same laser beam light that was used to record it. If a different laser frequency or another type of light is used, the reconstructed image wont exactly match the original. Yet, the most common holograms are visible in white light. These are reflection-type volume holograms and rainbow holograms. Holograms that can be viewed in ordinary light require special processing. In the case of a rainbow hologram, a standard transmission hologram is copied using a horizontal slit. This preserves parallax in one direction (so the perspective can move), but produces a color shift in the other direction. Uses of Holograms The 1971 Nobel Prize in Physics was awarded to the Hungarian-British scientist Dennis Gabor for  his invention and development of the holographic method. Originally, holography was a technique used to improve electron microscopes. Optical holography didnt take off until the invention of the laser in 1960. Although holograms were immediately popular for art, practical applications of optical holography lagged until the 1980s. Today, holograms are used for data storage, optical communications, interferometry in engineering and microscopy, security, and holographic scanning. Interesting Hologram Facts If you cut a hologram in half, each piece still contains an image of the entire object. In contrast, if you cut a photograph in half, half of the information is lost.One way to copy a hologram is to illuminate it with a laser beam and place a new photographic plate such that it receives light from the hologram and from the original beam. Essentially, the hologram acts like the original object.Another way to copy a hologram is to emboss it using the original image. This works much the same way records are made from audio recordings. The embossing process is used for mass production.