High School Students’ Conceptions about Energy in Chemical Reactions (focusing only in exothermic and endothermic reactions). Aim The aim of this study is to investigate students’ understanding of the energy concept in chemical reactions particularly in endothermic-exothermic reactions. Both qualitative and quantitative methodology was used for this investigation. A twenty-item multiple choice test was developed about the topic to measure the students’ understandings. This concept test was
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1. Determine the order of the reaction A --> 2B + C from the following data obtained for [A] as a function of time. time | [A] | 0 min | 0.80 M | 8 mins | 0.60 M | 24 mins | 0.35 M | 40 mins | 0.20 M | ------------------------------------------------- Use diferential and half life. 2. Balance the equation below and determine the rate expression using the given data. Find k with units. N2 + H2 ---> NH3 (all gaseous) [N2] (mole/L) | [H2] (mole/L) | Initial Rate (mole/L /min)
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Aldol In this preparative lab‚ an aldol (trans-p-anisalacetophenone) was produced from the reaction between p-anisaldehyde and acetophenone with the presence sodium hydroxide. The reaction also showed the importance of an enolate and the role it played in the mechanism. Sodium hydroxide acts as a catalyst in this experiment and is chosen because of its basic conditions and pH. The acetophenone carries an alpha hydrogen that has a pKa between 18 and 20. This alpha hydrogen is acidic because of its
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endothermic reaction happened everywhere around us. Basically exothermic and endothermic reaction is transfer energy to the surroundings and take in energy from the surroundings (BBC GCSE bitesize). If the reaction forward ，then is exothermic.If the reaction is the backwards ‚then is endothermic. When a reaction take place‚ the energy started to transfer from different object to the surroundings or take away energy from the surroundings. When temperature started to change. Exothermic Reaction An exothermic
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The hypothesis If a chemical reaction occurs‚ then there will be indicators of a chemical change‚ was supported throughout this experiment. Throughout this experiment there were several reactions that took place‚ and an indicator of such chemical reactions could be seen throughout each one. The first piece of identifiable evidence was present in the first step‚ which was when copper (II) nitrate and sodium hydroxide were combined. When stirred‚ a blue precipitate formed at the bottom of the test
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determine the reaction time of the test participant and using the subtractive method identify the selection time and identification time of the participant. The experiments had one participant who participated in a total of 6 experiments; two experiments required a simple reaction with a single stimulus and 4 experiments that required a more complicated reaction. Keywords Subtractive method – the procedure of estimating the time it takes to perform various cognitive operations. Simple reaction – this
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SN1 Reactions For SN1 reactions it’s important to have a good leaving group because this reaction occurs in two steps. Because alcohol is such a poor leaving group it needs to be helped by silver nitrate to help promote the ionization of the alkyl halide. This helps form the products of the SN1 reaction. 2-chlorobutane This reaction didn’t occur because the carbocation isn’t stable enough for an SN1 reaction. 2-bromobutane This reaction occurred in 32 seconds. This reaction occurred quickly
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Coursework Rates of Reaction Research The rate of reaction tells us how quickly a chemical reaction takes place. It is important for people in industry to know how fast a reaction goes. They have to know exactly how much of their product they can make each hour‚ day or week. In a shampoo factory‚ the rate might be 100 bottles per minute. We can’t work out the rate of a reaction from its chemical equation. Equations can only tells us how much product we can get. They don’t say how quickly
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Reminder: These notes are meant to supplement‚ not replace the laboratory manual. SN1 Reaction Notes Background and Application Substitution Nucleophilic First Order (SN1) reactions are one of the most common type of organic reactions. SN1 reactions can be used to make a wide variety of new compounds. In this experiment‚ t-amyl alcohol will be converted by a SN1 mechanism to 2-chloro-2-methylbutane. Safety Precautions Concentrated Hydrochloric Acid is 12M. It will cause visible destruction
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Lab #5: Grignard Reaction – Synthesis of Triphenylmethanol John Kang Chem 152L Performed: 7/20/04 Date submitted: ________________ Lab Partners: Sang Lee‚ Vicky Lai TA: John Stanko Abstract: This experiment explored the synthesis of triphenylmethanol through the use of Grignard reagents. The percent yield of the product was 10% on a relatively humid day. The melting point was calculate to be 127.2oC with a literature value of 162oC. An IR spectrum of the product was taken and used
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