Chemistry revision - atoms,rocks and metals
Chemistry Revision C1 1.1 - Fundamental Ideas Atoms, elements and compounds All substances are made of atoms. Elements are made of only one type of atom. Chemical symbols are used to represent atoms. Compounds contain more than one element. Atomic Structure The nucleus of an atom is made of protons and neutrons. Protons have a positive charge, electrons have a negative charge and neutrons are not charged. The atomic number (or proton number) of an element is equal to the number of protons in the nucleus of its atoms. Elements are arranged in order of their atomic numbers in the periodic table. The mass number is the sum of the protons and neutrons in the nucleus of an atom. The arrangement of electrons in atoms The atoms of the unreactive noble gases all have very stable arrangements of electrons. Electrons in atoms are in energy levels that can be represented by shells. Electrons in the lowest energy level are in the shell closest to the nucleus. Electrons occupy the lowest energy levels first. All the elements in the same group of the periodic table have the same number of electrons in their highest energy level (outer shell). Forming Bonds When a metal reacts with a non-metal, ions are formed. Metal atoms lose one or more electrons to form positively charged ions. Non-metal atoms gain electrons to form negatively charged ions. The oppositely charged
Learning checklist for 1.2: How do rocks provide building materials
Learning checklist for 1.2: How do rocks provide building materials Limestone Limestone, containing the compound calcium carbonate (CaCO3), is quarried and can be used as a building material. Calcium carbonate can be decomposed by heating to make calcium oxide (quicklime) and carbon dioxide. This is classed as a thermal decomposition reaction If the mass of calcium carbonate is measured in the crucible (on the right) before and after heating the mass will decrease because mass is lost due to CO2 being given off. The precision of this experiment can be increase by using a mass balance that measures to more decimal places. The best way to ensure all the carbonate has decomposed is to heat to constant mass (which means to repeatedly heat and cool, weigh, heat, cool, weigh – until no further change is mass is seen. Carbonates of other metals decompose on heating in a similar way, although some in group 1 do not decompose. Making Cement Cement is produced by roasting powdered limestone with powdered clay in a rotary kiln. In the kiln on the right the fuel (methane) reacts with oxygen from the air to produce CO2 in the waste gases. This reaction produces the heat to decompose the limestone. CO2 also is given off by the decomposing limestone The Argon and Nitrogen in the waste gases come from unreacted air. Quicklime (calcium oxide) reacts with water to produce
Fractional Distillation occurs when a mixed liquid is heated up until each component or fraction boils and evaporates
Fractional Distillation is the process where a mixture separates into its different components or fractions, examples can be separating chemical compounds by their boiling point by heating them to a temperature where one or more of the compound's will vaporize. This is a special type of distillation. Generally the component parts of the compound start to boil at less than 25°C from each other under a pressure of one atmosphere. Fractional Distillation occurs when a mixed liquid is heated up until each component or fraction boils and evaporates out of the initial liquid. This occurs because different fractions have different boiling points, when the boiling point for a certain compound is reached the vapor being evaporated off lands in a different container where there will be a more pure sample of that compound. Just like distillation, fractional distillation works because the different compounds in the mixture have different boiling points. Fractional Distillation is used very commonly in petroleum refineries, petrochemical and chemical plants and natural gas processing plants. In petroleum refineries fractional distillation is used to separate the different fractions found in crude oil. The process of how crude oil separates through fractional distillation is as follows, first the crude oil is inserted through a furnace where it is heated, and then the crude oil moves
Pollution and Global Warming report.
Substances dumped into a river will end up in the sea. The biggest pollution problem is global warming. This happens when greenhouse gases, such as CO2 are released into the atmosphere, trapping heat and causing the planet to warm up. Chemical pollutants have been responsible for affecting the reproductive organs of fish, alligators and polar bears, stopping them from making babies. The greenhouse effect What is the greenhouse effect? About 30 gases are made by human activity have been identified as contributing to the greenhouse effect. These are sometimes called greenhouse gases. The main gases are carbon dioxide, methane, CFCs and nitrous oxide. Sunlight reaches the Earth's surface, is reflected off it, and is prevented from escaping from the atmosphere by this layer of gases, which acts like glass in a greenhouse. Up to a point, the greenhouse effect is a natural process, and naturally occurring carbon dioxide is not dangerous. Without greenhouse gases, the average temperature of the Earth would be -19C, which is to cold for us to live? What part have humans had in the greenhouse effect? We have made the amount of carbon dioxide in the atmosphere go up by burning fossil fuels, like as coal, oil and petrol. Cows, rice fields and rubbish rotting in landfill sites make methane, and aerosols. The removal of trees and deforestation is also thought to increase the
My case study is about global warming and why it happens.
Why is Global warming happening? Contents.... Introduction ... My case study is about global warming and why it happens. I am researching about global warming being caused naturally and manmade. Global warming is an issue because there is increase on co2 (carbon dioxide). The issues are that there are greenhouse effects; greenhouse gases and carbon footprint that can make the climate change for e.g. in Greenland the glaciers are melting because of the heat and make the deep water increase reaching Iceland coasts. Throughout my case study you will be reading about the greenhouse effect, global warming and the greenhouse gases and what it is. As well as this throughout my case study I will be telling you about the naturally made effects of global warming and also manmade effects of global warming. Greenhouse effects and Greenhouse gases Greenhouse effect is when the suns light heat called solar radiation. Solar radiation goes in the earth's atmosphere and some of it is absorbed on the earth's surface. Some of the solar radiation reflects from the atmosphere and the earth's surface. Infrared radiation goes from the surface to the space. Greenhouse effect is when the infrared radiation heat is being absorbed by the greenhouse gas, the main greenhouse gases is water vapour, methane, carbon dioxide. The greenhouse gases are 1% of the atmosphere which orders and traps the heat
Atmospheric pollutants in the lower atmosphere essay.
Atmospheric pollutants in the lower atmosphere The atmosphere becomes polluted by both natural processes and the activities of humans. Volcanoes can release toxic gases including sulfur dioxide. Lightning produces toxic nitrogen oxides and ozone. Let us examine some gases that pollute the lower atmosphere. Lower atmospheric pollutants often include particulates such as soot from forest fires and the exhaust from industry. Metal dusts and concrete dusts also are atmospheric pollutants, as are vapours from solvents used in industry and domestically. Carbon dioxide The concentration of carbon dioxide has shown a gradual increase during the twentieth century. The burning of fossil fuels such as coal and oil products has caused this gradual increase in carbon dioxide levels. This increase in carbon dioxide is one of the factors that scientists believe has added to global warming. This is sometimes referred to as the 'enhanced greenhouse effect'. Carbon dioxide absorbs infrared (IR) radiation that is re-radiated by the Earth's surface. This process is vital in ensuring that the Earth does not lose too much heat and become a cold, lifeless planet. Too much carbon dioxide, however, leads to higher heat retention with consequent changes to the abiotic and biotic environment. Carbon monoxide Carbon monoxide is a lower-atmospheric pollutant. Road traffic emissions account for up
What factors affect the amount of copper-plated on the cathode by electrodes of copper sulphate?
What factors affect the amount of copper-plated on the cathode by electrodes of copper sulphate? Introduction: Electrolysis is the decomposition of a substance by passing an electric current. Some substances are strong and others weak, depending on how they can be decomposed. E.g. sodium chloride is a strong electrolyte and water is a weak electrolyte. Oil is not an electrolyte because it does not decompose by passing an electric current. Variables: . Time - The longer the electrodes are in the solution the more mass will be lost at the anode and gained at the cathode. 2. Current - With a greater charge, the copper at the anode has to decompose more to give more electrons. 3. Temperature of electrodes - If an electrode gets hot it will expand. 4. Concentration of copper sulphate - The stronger the solution the more copper ions there will be to take electrons from the cathode. Surface area of electrode - When the electrode has a larger surface area there is more surface for the copper ions to dissolve into the solution from, and the greater the surface area the greater the loss in mass at the anode. Chosen variable: I have chosen to investigate the variable of current. As it will give me good results and will be more accurate. Prediction: I predict that the greater the current the greater the gain in mass at the cathode. I predict this because, electrons flow
Electrolysis Using Copper Sulphate And Copper Electrodes
Electrolysis Using Copper Sulphate And Copper Electrodes Introduction In this experiment copper sulphate will be electrolysed using copper electrodes to find the loss of mass of the anode. The copper anode will be weighed before and after the experiment. Each time the experiment is done the time will be increased by 2.5 minutes until 25 minutes is reached. So the first experiment will last 2.5 minutes and the second 5 minutes. The results will be plotted on a graph of loss of mass against time. Aim To find the loss of mass of anode when electrolysing copper electrodes using copper sulphate solution for different times. Background Information Electrolysis is used to purify copper. Ken Gadd and Steve Gurr state that electrolysis is "the process of decomposition"1. For electrolysis to occur the circuit shown below must be set up: The battery is used to supply the energy for the free electrons inside the wires to move. The wires are in turn used to connect the two electrodes (conducting rods) to the battery. The electrodes are then placed inside the electrolyte (the substance that ions move in), which in this experiment is copper (II) sulphate solution. In industry the impure copper would be used as the anode and the pure copper used as the cathode. When the electrodes are connected to the battery the anode should be positively charged and the cathode negatively charged.
Are we making the best use of crude oil?
Are we making the best use of crude oil? Crude oil is an important substance used in everyday life e.g. paint, fuel, fertilisers, medicine and many more. As you can see crude oil plays a huge impact on our lives, however are we using crude oil to the best extent? The use of crude oil is at an unsustainable rate, one day we may run out therefore in this essay I am going to be trying to answer this decisive question 'are we making the best use of crude oil?' Crude oil, also well-known as a fossil fuel, is the term used for "unprocessed oil". Naturally derived from decaying plants and animals, crude oil is a fossil fuel. It is made up of various elements or compounds such as carbon, hydrogen, sulphur, nitrogen, oxygen, metals and salts. Due it to its constituency, crude oil differs in colour from plain to tar-black and in viscosity, from water to nearly solid. The main component of crude oil is hydrocarbon, which contains a lot of energy. Hence, crude oil is used in generating many forms of energy such as gasoline, diesel and other fuel oils. Products made from crude oil are mostly synthetic products which are far more costly than Natural products. If the industry takes a big change and decided to create synthetic items, the overall effect will be costly and may lead us into recession if we get out of this one. Since crude oil is starting to be scarce the prices of fuels are
Investigating how the voltage produced by a simple cell is related to the reactivity series.
Investigating how the voltage produced by a simple cell is related to the reactivity series Scientific knowledge Simple cell: 2 different metals that are connected will generate an electric current when placed in an electrolyte. An electrolyte is a conducting solution containing ions. Simple cell Reactivity A metal's reactivity depends on its ability to lose or gain electrons. How a simple cell works: So H ions for example could touch the -ve rod and become discharged producing hydrogen gas. N.B. If there is a flow of electrons between the 2 metals there will be a potential difference created (voltage). Example (metals mg and cu) For mg the metal loses electrons, which flow through the external wire to the cu. Mg dissolves forming mg ions. Cu gains electrons from the mg becoming negatively charged. These electrons begin to repel each other causing the flow to cease. It is possible that the electrons can attract H ions in the electrolyte. Possible key variables . Identity of metals 2. Size of metal (surface area) 3. Identity of electrolyte 4. Concentration of the electrolyte 5. Purity of metal 6. Temperature I have chosen to vary the identity of the metals as in my title for the experiment it suggests I do so. I will keep one metal the same (constant) and vary the other. I have chosen copper as the standard metal, as it is easily obtainable and of low
