Vegetative reproduction (vegetative propagation‚ vegetative multiplication‚ vegetative cloning) is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores. It can occur naturally or be induced by horticulturists. Although most plants normally reproduce sexually‚ many have the ability for vegetative propagation‚ or can be vegetatively propagated if small pieces are subjected to chemical (hormonal) treatments. This is because meristematic
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The Earth’s atmosphere has changed over billions of years‚ but for the past 200 million years it has been much as it is today. We are‚ however‚ causing our atmosphere to change by human activity. Burning fossil fuels and deforestation are two examples of human effect on the environment. Composition of the Earth’s atmosphere The composition of air You need to know the proportions of the main gases in the atmosphere. The Earth’s atmosphere has remained much the same for the past 200 million years
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early atmosphere - earth roughly 4 billion yrs old - created by volcanoes erupting + releasing gases - contained mostly co2 + water vapour - earth cooled + water vapour condensed to form oceans - co2 dissolved into oceans + used to form marine organism shells which were compacted to form sedimentary rock - plants evolved to photosynthesise‚ takingin co2 + releasing oxygen - scientists don’t kno where all nitrogen came from bc they weren’t there to record evidence but most theories suggest
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4th form Chemistry questionnaire 1. All of the following structures show the same molecule‚ except one. Which structure is different? H H H H A) H -- C -- C -- C --- C -- H B) CH3 CH2 CH2 CH3 H H H H H H -- C -- H CH3 C) H H D)
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6-Dimethyl-3-heptyne 1‚6-Heptadiyne Common names: prefix the substituents on the triple bond to the name “acetylene” IUPAC name: Common name: 2-Butyne D imethylacetylene 1-Buten-3-yne Vinylacetylene Physical Properties Similar to alkanes and alkenes of comparable molecular weight and carbon skeleton 2-Butyne 1-Pentyne Melting Point Formula (°C) -81 HC CH CH3 C CH -102 CH 3 CH2 C CH -126 -32 CH3 C CCH3 CH 3 ( CH2 ) 2 C CH -90 1-Hexyne CH 3 ( CH2 ) 3 C CH
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(note: there is CO2 solid‚ its dry ice) – Complete combustion: ▪ hydrocarbon + oxygen [pic] water + carbon dioxide – Displacement reactions: ▪ Y + X (anion)[pic] X + Y (anion); where Y > X on activity series or Eo table. • Alkene/alkane reactions: – Cracking of pentane: ▪ pentane [pic] ethylene + propane ▪ C5H12 (g) [pic] C2H4 (g) + C3H8 (g) – Hydration of ethylene (the reverse can also happen known as de-hydration‚ where concentrated acid is used): ▪ ethylene
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Grignard reaction Abstract: In this laboratory‚ triphenylmethanol was synthesised from reacting benzophenone and bromobenzene using Grignard reaction. As the reaction was to set up to produce a Grignard reagent and then recrystallize it to obtain pure sample. The percentage yield obtained was 55% and its melting point was 161 co which is within the literature value 160-163 co. In addition to that the IR spectroscopy confirmed the molecule structure to be triphenylmethanol. Introduction: The Grignard
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Production of materials 1B – identify the industrial source of ethylene from the cracking of some of the fractions from the refining of petroleum Industrial source of ethylene (ethene) * Obtained from Crude oil – fractional distillation * Heated to high temps * Components vaporise and rise up tower where condense and collect * Lower the boiling point‚ higher up tower compound rises * Separates crude oil into fraction each with different boiling range - Catalytic Cracking
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Edexel IGCSE Chemistry Revision Notes IGCSE Chemistry Triple Award Revision Guide Topic Introduction to chemistry Atomic Structure Structure and Bonding – Ionic Bonding Structure and Bonding – Covalent and Metallic Bonding Organic Chemistry - Alkanes Organic Chemistry – Alkenes / Addition Polymerisation Organic Chemistry – Alcohols / Condensation Polymerisation Calculations Periodic Table Reactivity Series and Metal Extraction Electrolysis Energetics Acids‚ Bases‚ Salts and Neutralisation Preparing
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the refining of petroleum Catalytic cracking is the process whereby high molecular weight fractions are broken down to low molecular weight ones. This process is used in petroleum refineries where crude oil is broken down to smaller alkenes and alkanes‚ until ethene‚ propene‚ (or both) are formed. Catalytic Cracking allows greater output of high-demand products. Identify that ethylene‚ because of the high reactivity of its double bond‚ is readily transformed into many useful products Ethylene
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