Breaking Investigation
An airbrake is a device using air resistance (air friction) to slow down an object. An airbrake is a very efficient way of braking, which is why it can be found in devices such as trains, lifts, hoists, etc. THE TASK The task is to investigate what effects the degree of braking, how your chosen factor(s) is/are related and why you think it/they effect the braking in this/these way(s). METHOD The air brake was made up using a knitting needle, glass tubing, a cork with slits, and 8 (8cm x 3cm) cardboard blades. As you can see in the diagram below, the knitting needle acts as an axle, which allows the glass tube to move freely. To the glass tube we attached a string which was 185cm long. At the other end of the string we attached a hook which could hold the weights and act as the lever. Finally we attached the air brake to a clamp for support and placed it on a table and made sure the air brake was directly 2 meters above the ground. To make the experiment fair we will always keep the air brake at the same level because if the air brake is at different heights during the experiment, the force of gravity could upset our results by giving us an anomalous result. To make it a fair experiment we will also keep the area of the 8 cardboard blades the same so that when the blades push up against gravity, each trial will be fair. Also to make it a fair experiment we will take
Hydrogen-Oxygen Fuel Cells: Case Study
HSC Chemistry Research Assignment Topic: The Production of Materials Lloyd Ruz Cell Type: Hydrogen-Oxygen Fuel Cell The structure of the cell The Hydrogen-Oxygen Fuel cell uses hydrogen as its fuel source. The basic structure of such a fuel cell is outlined below: Figure 8A The chemistry of this cell will be outlined below. The chemistry and function of the cell Two separate half-cell reactions occur to produce a flow of electrons (current): * At the Anode, Hydrogen gas is oxidised, allowing protons (H+) to enter the proton exchange membrane (or polymer electrolyte membrane, coincidentally, both mean the same thing, in this case, and have the same abbreviation: PEM) and electrons (e-) to travel around a circuit to the cathode. Hence the following oxidation reaction takes place: * At the Cathode, protons that have permeated through the membrane and oxygen molecule which has dissolved through the electrode are reduced by electrons that have completed the circuit. Hence, the following reduction reaction takes place: › . . . . . . . . (1,5,6,7,8) These reactions and the flow of electrons are shown in Figure 8A (above) and again below in Figure 9 Figure 9 When the electrolyte is an alkaline (as in a Alkaline fuel cell with an anion exchange membrane), such as in Figure 6A (below), the following half reactions take place: Anode: H2(g) +
Gold. For thousands of years, gold has been regarded as the finest and most precious metal known to man. In this CDA, I will try to find out why gold is so valuable.
GOLD Uttam Sharma Centre-Devised Assessment For thousands of years, gold has been regarded as the finest and most precious metal known to man. In this CDA, I will try to find out why gold is so valuable. Gold INTRODUCTION PROPERTIES Gold is a metal which has had many purposes over the thousands of years. It has been used for jewellery, money, decoration and, more recently, in tooth fillings and electronics. It's a soft, yellow, metal with useful thermal and electrical properties. Unlike other metals like silver and copper, gold does not tarnish over time and use. Tarnish is a dark layer which forms over some metals such as copper, brass and aluminium. It is very dense metal, at 19.32 g/cm3. To give you an idea of just how heavy gold is, think of it this way: the mass of 1 litre of water is 1 kilogram. The mass of 1 litre of gold is 19.32 kilograms. Imagine carrying a 1-litre water bottle that weighs over 3 stone. The colour of gold is also called gold. It has an atomic number of 79, and a relative atomic mass of 196.97. The symbol for gold is Au, which comes from the Latin word for gold, 'aurum'. A gold leaf is gold that has been beaten into very thin sheets. Of all elements, gold is the most malleable and ductile. 1 gram of gold can be beaten down to cover an area of 1 square metre. Malleability is the ability of a material to be flattened down into a thin sheet by
What "Carried the Trick"? Mass exploitation and the decline of thought in Ray Bradbury's 'Fahrenheit 451.'
What "Carried the Trick"? Mass exploitation and the decline of thought in Ray Bradbury's 'Fahrenheit 451.' * There is an interesting dichotomy in Ray Bradbury's 1953 Fahrenheit 451, a noticeable gap between the message that the author and we the readers receive from the novel and the message that the text actually seems to support. While I realize that some see little use for such old-fashioned attention to the text itself, Fahrenheit 451 is such an overtly didactic work that it almost invites such examination. Surely even the staunchest reader-response critic would agree that Bradbury is trying to sell the readers on ideas that he has put into his story. Yet there is a discrepancy between the ideas the author is selling--and readers are buying--and the ideas he has let the whole rest of the text support. I suggest this not necessarily to label it as a weakness but to show that the novel is thereby just a little bit richer and probably truer to life than many have supposed. The discrepancy lies in the book's subtle treatment of the relationship between mass exploitation and the decline of thought. Fire Captain Beatty, the novel's chief book-burner, explains that "technology, mass exploitation, and minority pressure carried the trick" of supplanting independent thought with conformity and leading to censorship (58). Clearly Bradbury wants us to notice these three culprits in
Our experiment consisted of two samples of water containing unknown substances, and our objective was to identify the compound present in the substance.
Chemical Detection Uttam Sharma CHEMICAL DETECTION Introduction In this CDA, I will attempt to explain everything about our experiments which we performed in class. We did these experiments in order to identify the substance present Our experiment consisted of two samples of water containing unknown substances, and our objective was to identify the compound present in the substance. Since the substance was dissolved in water, we had to separate the water from the substance, and then execute a series of tests which would eventually help us to determine the substance in the sample. Water Water (H20) is vital for all types of life, animals and plants. A molecule of it is made up of two hydrogen atoms and one oxygen atom. It has freezing point of 0°C and a boiling point of 100°C at sea level (on top of Mount Everest it boils at just 68?, due to changes in atmospheric pressure). Water covers 71% of the Earth's surface and is colourless and odourless (no smell). It is used every day for drinking, washing up, farming and in many other important places. This is where hard and soft is important. Hard water is water that contains large amounts of minerals. Mostly it comprises of are the cations of calcium (Ca2+) and magnesium (Mg2+). There are other metals present in hard water such as bicarbonates and sulphates. Calcium comes into the water through in the form of limestone
Identifying an Ionic Compound. Objectives: To learn and test for metal ions and non-metal ions and then apply them to discover the identity of an unknown ionically bonded substance
Identifying an Ionic Compound- Introduction Ionic compounds are defined as being compounds where two or more ions (an atom or group of atoms with an overall electrical charge) are held next to each other by electrical attraction. One of the ions has a positive charge - called a "cation", and the other has a negative charge - called "anion". Cations are usually metal atoms and anions are either nonmetal or polyatomic ions (ions with more than one atom). Usually, when we have ionic compounds, they form large crystals that you can see with the naked eye. Table salt is one of this- if you look at a crystal of salt, you can see that it has in irregular cube shape. This is because salt likes to stack in little cube-shaped blocks. When forming salt, Na readily loses an electron and Cl readily gains an electrons so both can become stable. Heat is added in the reaction so Na burns brightly in CL gas and a white solid forms on the sides of the container. This solid is salt, or sodium chloride. When the chlorine atom gained an electron, the atoms arrange themselves in a lattice. The force of attraction between a cation and anion is a very strong bond called an "ionic bond". This is an electrostatic attraction. An ionic bond happens between a metal and a nonmetal. Properties of salts: 0. All ionic compounds form crystals. 0. Ionic compounds tend to have high melting and boiling
Titration is used in neutralisation reactions:
ANALYSING Titration is used in neutralisation reactions: However, this method is also used to find the morality of acids and alkaline. In this investigation I have used titration to find out how much acid (HCl) is needed to neutralise the alkali (Lithium hydroxide-LiOH), thereafter using this number to find the relative atomic mass of lithium. The relative atomic mass of a substance varies from substance to substance. This number is used so that the masses of atoms, of elements could be compared. The symbol used is (Ar). A mole is the mass of a substance that has the same number of atoms as there are in 12g of carbon 12. The number of atoms in one mole is known as "Avogadro's constant", and has a value of 6.02 x 10²³mol ¹. Procedure (1): I will assume that (1) mole of gas occupies 24000cm³ at room temperature and pressure. * The number of moles of hydrogen: No. of moles = volume / 24000 = 154 / 24000 = 0.00641667mol = 0.01 mol (2dp) I have used this equation as it indicates that if a gas is kept at equal volumes in the same conditions it contains the same number of molecules. * The number of moles of lithium: The equation above suggests that there is a 2 : 1 ratio. This means that for every (1) mole of hydrogen there are (2) moles of lithium. Therefore the number of moles of lithium needs to be doubled. 2 x 0.00641667 = 0.0128333 mol = 0.01 mol
Ions - a qualitative analysis on our chemicals by flame testing.
Ions Introduction When an atom absorbs light or when an atom bonds an electron can be gained or lost and what is left is an ion. If the ion gains an electron it has become a negative ion and if it losses an ion it becomes a positive ion. This is because the balance of the electrons protons is disturbed. Nature is no stranger to science and within the great outdoors in area which mountainous fresh countryside areas are. It has statically been proven that these areas which make u feel comfortable and relaxed contain a high concentration of negative ions. Where as areas with high concentrations of positive ions seem to make us feel uncomfortable and irritable. After a storm the air feels clean and refreshed this because they are filled with negative ions. Many people find the atmosphere before a storm is heavy and oppressive. This is due to the build up of positive ions within the air. Within areas high with a high concentration of positive ions it has be known to trigger of allergies and asthma. It is all very well knowing what ions are and how they create an affect on us but how can they be recognised. The most obvious and fairly accurate way at the present time is qualitative analysis. Qualitative analysis is a body of features used to identify or quantify the chemical composition of a chemical substance. When seeking to identify a chemical in a substance scientist carry
To find the densities of an unknown solid and liquid in order to determine what they are.
Name: Natausha Tackett Lab Partner(s): Sabrina Sekic and Terri Moore Lab Section #: 3 Title: Data and Calculations Date: September 7, 2005 Purpose: To find the densities of an unknown solid and liquid in order to determine what they are. Materials: Toluene(V) and Zinc(E) Equipment: A stoppered flask, and an analytical balance Safety: To begin the experiment, we wore our safety goggles. We were careful with the chemicals as to not get it on our hands, or clothes. When we were finished with our chemicals, we poured our "unknown liquid" into a container, specifically for that, located under the hood. We put our metal in the designated place, rinsed our flasks and the stoppers, and left them to dry. Procedure: In the 1st part of the experiment, we were trying to find the density of an unknown liquid. To perform this experiment, we found the mass of the empty stoppered flask by weighing it on the analytical balance. We then found the mass of the stoppered flask plus water. By subtracting the mass of the empty stoppered flask from the mass of the stoppered flask filled with water, we found the mass of the water. Next, we found the mass of the stoppered flask plus an "unknown liquid." (V) By subtracting the mass of the empty stoppered flask from the mass of the stoppered flask filled with an unknown liquid, we found the mass of the unknown liquid. Next, through
Mass Spectrometer.
Mass Spectrometer Used to determine * the relative isotopic masses and abundance of isotopes * the relative molecular mass (Mr) and abundance of the organic compound Principles of the mass spectrometer * Apparatus enclosed in total vacuum, so that there are no colisions between the sample being investigated and the atmospheric air or the residue from previous samples. * Vacuum pump is to reduce pressure so less thermal energy is needed to vaporise the sample. The pump is to remove any traces of the previous sample traces of the air. * Sample under analysis must be vaparised i.e. converted to gaseous state. This is achieved by heating it in the furnace. * Sample then enters the ionisation chamber; here the sample is bombarded by a beam of high energy electrons. A beam of these high energy electrons bombard the atoms causing them to loose an electron. A removal of an electron from the atom is known as ionisation. This results in the formation of positively charged ions (cations), mainly single charged ions. If the sample is simple the molecules are ionised by being bomdarded by high energy electrons, causing bonds to vibrate and weaken, some bonds between molecules to produce small pieces of the original molecule known as smaller fragments and/or free radicals. Smaller pieces of the original lecule are known as moecular
