Investigating Factors Affecting the Rate of Photosynthesis.
AT2 Biology Investigating Factors Affecting the Rate of Photosynthesis Stella Boachie How does Light Intensity Affect the Rate of Photosynthesis? Aim The aim of this coursework is to investigate whether light intensity affects the rate of photosynthesis. To do this, I will place a piece of Canadian pondweed in varying light intensities and observe the amount of oxygen given off. Introduction Photosynthesis is the process by which green plants and certain other organisms transform light into chemical energy. In green plants, light energy is captured by chlorophyll in the chloroplasts found in the palisade cells of the leaves and used to concert water, carbon dioxide and minerals into oxygen and energy rich organic compounds (sugar) that are the basis of both plants and animal life. The first step in photosynthesis is Light Dependent Processes (Light Reaction). Light strikes chlorophyll in such a way as to excite electrons to a higher energy state. In a series of reaction, the energy is converted along an electron transport process into ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate). Water is split in the process, releasing oxygen as a by-product of the reaction. The ATP and NADPH are used to make C-C bonds in the next stage of photosynthesis, Light Independent Process (Dark Reaction). In the Light Independent Process, carbon
Chem MC analysis. In which of the following cases may it obtain a complete neutralization? (1)25.0 cm3 of 0.120 M sulphuric acid and 50cm3of 0.120M sodium hydroxide solution (2)50.cm3 of 0.5 M Sodium hydroxide and 0.025 moles of aqueous ammonium chlorid
Chemistry 4A Ivan Liu Chun Pok (12) Non-practical task Mc analysis Topics: Neutralization, Reaction between alkali and ammonium compound, Strength of Acid and Alkali, Reacting Masses, Volumetric Analysis In which of the following cases may it obtain a complete neutralization? (1)25.0 cm3 of 0.120 M sulphuric acid and 50cm3of 0.120M sodium hydroxide solution (2)50.cm3 of 0.5 M Sodium hydroxide and 0.025 moles of aqueous ammonium chloride (3)20.0cm3 of 0.100M phosphoric acid and 30.0cm3 of 0.200 M potassium hydroxide solution (4)Dissolve 0.2025g of solid sodium hydroxide in water and make up to 250cm3 of solution, then 25.0cm3 of this solution is added to 50.0cm3 of 1M hydrochloric acid A.2 B.1, 3 C.3, 4 D.1, 2, 4 Option 1: H2SO4(aq) + 2NaOH(aq)--> Na2SO4(aq) +H2O(l) Mole ratio of H2SO4 : NaOH = 1:2 ?Using the formula, Molarity of a solution M or mol dm-3 = Number of moles of solute (mol) / Volume of solution (dm3) ?Number of moles of solute (mol) = Molarity of a solution M or mol dm-3X Volume of solution (dm3) Number of moles of H2SO4 given: 0.12 X (25.0 /1000) = 0.003mol Number of moles of NaOH given: 0.12 X (50.0/1000) = 0.006mol Mole ratio of H2SO4 : NaOH = 0.003 /0.006 = 1:2 Therefore, option (1) is correct. Option 2 : NaOH(aq) + NH4Cl (aq)--> NaCl(aq)+ NH3(g) + H2O(l) Mole ratio of NaOH : NH4Cl
Anti-acids
Rates of Reaction in Antacids Aim I plan to investigate the effectiveness of indigestion tablet on HCl. I will take five different tablets containing a specific pH of alkali and discover how long it takes for the indigestion tablet to neutralise the acid. The test will tell me which is the fastest acting tablet is in the case of indigestion. Antacids Antacids are bases and most of them react on the excess build up of stomach acid and neutralises the acid. The most common of these bases are hydroxides, carbonates or bio carbonates. Neutralisation If you have a weak acid you can eliminate the acidic pH by combining it with a weak alkali. Neutralisation is a chemical reaction which is caused by combining both an acid and an alkali, this reaction causes both the solutions to cancel each other out, and this reaction leaves you with water and salt. Neutralisation is simply the combination of hydroxide ions OH and hydrogen ions H+ this process leaves you with the molecule H2O and forms salt. A Catalyst Catalyst are use to speed up a reaction without being used up. In some reaction like digestion catalyst are essentially needed to speed the process or digestion would take too long to gain nutrients. A catalyst breaks down a substance to provide a larger surface area to speed up the process. The Rate of Reaction The amount of time the reaction occurs. Magnesium +
Is Aluminium a Suitable Metal for Manufacturing Bicycles?
Is Aluminium a Suitable Metal for Manufacturing Bicyces? Extraction Process for Aluminium The ore of aluminium is Bauxite and it contains 52.9% aluminium and 47.1% oxygen. The extraction of aluminium takes three main stages: * The mining of bauxite * Refining of the ore to produce aluminium oxide * Electrolysis of aluminium oxide to produce aluminium Mining Bauxite is mined by removing the top layers of soil and then removing the ore from the area by use of explosives to break it into moveable pieces. The bauxite is then crushed on site, sometimes washed to remove soil and clay and then dried in a kiln or it may just be dried. It is then ready to be transported by railway or ships to refineries. Refining Bauxite is made of aluminium oxide-2-water (Al2O3.2H2O) and silicon (IV) oxide (SiO2) and iron (III) oxide (Fe2O3). The bauxite is refined to extract pure aluminium oxide: * The bauxite is ground * Then heated with concentrated NaOH (aq) * This forms a solution of sodium aluminate and sodium silicate, plus a residue of iron (III) oxide, which is removed. * CO2(g) is blown in and the sodium silicate remains in solution, but a precipitate if aluminium hydroxide is formed. * The mixture is then filtered, washed and heated to leave anhydrous aluminium oxide (alumina). * Al2O3 is left. Electrolysis This is how the aluminium and oxygen is separated, through
the chemistry of iron
Write an essay on the chemistry of iron Introduction Iron has an electronic configuration of . It is a d-block element. Also, iron is a transition metal. It has all the properties of a transition metal, including variable oxidation states, complex formation, coloured ions and catalytic properties. General properties of iron Like other metals, iron has a shiny surface. It conducts heat and electricity well. Iron is very tough, so it is always used as building materials. Moreover, iron is cheap when compared with other metals; therefore, it is widely used in all kinds of manufacturing. Variable oxidation states Since the successive ionization enthalpies of transition metals only increases gradually and in particular, the energy difference between 3d and 4s shells is very small, transition metals have variable oxidation states. Iron has two major oxidation states: +2 and +3. Fe2+: Fe3+: As Fe3+ has a half-filled 3d subshell, Fe3+ has extra stability over Fe2+. This can be reflected from the particularly low third ionization enthalpy. Fe2+ can readily be oxidized to Fe3+. Coloured ions and complex formation Complex is formed when ligands form dative covalent bonds with the central atom/ion. Transition metal ions like Fe2+ and Fe3+ can form complexes with ligands readily because they have large charge/radius ratio and low lying vacant d-orbitals available for
Effect of increasing charge on Mass of Copper Deposited.
Chemistry Coursework Effect of increasing charge on Mass of Copper Deposited Diagram Method * I will fist weigh the cathode * I will then set up the apparatus as shown in the diagram * Then switch the power pack on * I will wait 10 minutes and then weigh the cathode, I will do this for 50 minutes every 10 minutes My Independent Variable is the Charge My Dependent Variable is the Mass of the cathode The controlled variables are the concentration of Copper sulphate and the temperature Prediction: I can predict that there will be a positive coloration between the increase of charge and the amount of copper produced at the cathode. Scientific Explanation: Current is the flow of electrons in a circuit - in the case of electrolysis the flow is towards the cathode and away from the anode. Within the solution, the current flows because of the presence of negative and positive ions. Copper sulphate is an ionic salt, which contains no free electrons. However, it does contain ions (which are charged particles) fixed in a crystalline structure. When copper sulphate is dissolved, the copper sulphate solution becomes an electrolyte because the ions become free to move and they can conduct electricity. At the cathode, the copper ions, being more reactive than the hydrogen ions are deposited whilst the hydrogen ions
Escherichia coli and antibiotic resistanceIntroduction:Escherichia coli, short E. coli is an important bacteria that are
Escherichia coli and antibiotic resistance Introduction: Escherichia coli, short E. coli is an important bacteria that are found in the lower part of intestines of warm blooded animals, including human. People's feces for a day usually contain about 100 million or 10 trillion individuals of E. coli. E. coli is a major component of a bacterial system that helps to digest food particles. E. coli also has commercial uses. For instance, is used as an organic indicator for the sewage treatment to indicate the level of the concentration of poop pollutions in the water. However, uncontrolled growth of E. coli bacteria or the allocation of E. coli to other parts of the human body can be dangerous or even fatal. E. coli is also used in many laboratory experiments because they are cheap to acquire and easy to culture. When people are referring to bacteria that are resistant against penicillin, for instance penicillin resistant E. coli, these people are referring specifically to the ability of this bacteria population to produce an enzyme called penincillinase. Penincillinase is a general term describing a wide variety of enzymes that are capable of deterring penicillin invasion. A common type of penincillinase is plasmid-mediated extended-spectrum b-lactamases (ESbl) (bacteria can transfer genetic material through replication or plasmid). Plasmid-mediated means that the enzyme is
Revision of Atomic Structure
Revision of Chemical Bonding Bonding occurs between elements in order that they can obtain stable 'full shell' (noble gas) electron configurations. Types of bonding: ionic, covalent, metallic Ionic Bonding Transfer of electrons to create charged particles called ions Ionic compounds contain positive and negative ions whose charges balance. Usually found in compounds that contain metals combined with non-metals - electrons are transferred from the metals (to leave positive metal ions) to the non-metals (to create negative ions). e.g. sodium chloride NaCl e.g. magnesium chloride MgCl2 (simplified diagram - only outer shells shown) The ions are held together by the strong electrostatic attraction between opposite charges. In the solid they form giant regular structures called lattices. Greater charges generally means stronger forces, so MgO (Mg2+ O2-) has a higher melting point than NaCl. Properties of ionic compounds: Usually solid at room temperature with high melting points and boiling points. Usually hard Usually soluble in water Do not conduct electricity when solid, but can when molten or in aqueous solution because the ions are free to move. Covalent Bonding Sharing of electrons between atoms. Usually between non-metal atoms. Atoms overlap outer shells to create stable full shells. e.g. hydrogen H2 Shared pair of electrons is known as a single covalent
equilibrium constant
Experiment 13 Aim: To determine the equilibrium constant for esterification from ethanoic acid and propan-1-ol. Procedure: . 0.25 mole (equals to 14.3 cm3) of glacial ethanoic acid (density = 1.05 g cm-3) and 0.25 mole (equals to 18.8 cm3) of propan-1-ol (density = 0.8 g cm-3) was put into a clean, dry pear-shaped flask. It was mixed thoroughly. 2. 1.0 cm3 of the mixture was transferred by pipette to a 250 cm3 conical flask containing about 25cm3 deionized water and 2 drops of phenolphthalein indicator. It was titrated to end point with 0.50 M sodium hydroxide solution. The titre (V1 cm3)was recorded. 3. 8 drops of concentrated sulphuric(VI) acid was added to the remainder of the acid-alcohol solutions while continuously swirling the flask. Another 1.0 cm3 sample was titrated immediately. The titre (V2 cm3)was recorded. The difference between V1 and V2 Represents the volume to be subtracted from subsequent titration to correct for the amount of sulphuric (VI) acid present. 4. A few anti-bumping granules were added to the flask, and it was attached to a water-cooled reflux condenser. It was refluxed for 1 hour. The flask and its contents in an ice bath was cooled. 1.0 cm3 sample was removed from the flask for titration with the 0.50 M sodium hydroxide solution as before. The titre needed was recorded (V3)and was corrected for the sulphuric(VI) acid. 5. Refluxing was
Taxonomy is the branch of biology that deals with the identification and naming of living organisms
Mr. Miller Biology 401A Biology Essay BEGÜM COGAL A species is a genetically distinct group of organisms, which can interbreed and produce fertile, viable offsprings. External similarity is the common basis for identifying individuals as being members of the same species. Yet a bulldog, a terrier, and a golden retriever are very different in appearance, but they are all dogs because they can interbreed. People can also interbreed with one another, and so can cats, but people cannot interbreed with dogs or cats, nor can these with each other. This shows that individuals of a species are able to interbreed with one another but not with members of other species. Even if they could interbreed with members of other species they would not be able to produce fertile offsprings. For example, when horses and donkeys mate, they produce mules. However, these mules are infertile. They are unable to breed at all and bear offsprings of their own. Taxonomy is the branch of biology that deals with the identification and naming of living organisms. The Swedish biologist, Carolus Linnaeus (1707 - 1778) established a simple system for classifying and naming organisms. He developed a hierarchy, or in other words a ranking system for classifying organisms, that is the basis for modern taxonomy. Linnaeu's classification hierarchy included five levels: kingdom, class, order, genus, and
