Observations | Reaction Type | Complete and Balance | 1. When heated in oxygen‚ magnesium gives off a bright white flame. | combination reaction | 2Mg + O2-----> 2MgO | 2. Bubbling and fizzing occurs; the zinc appears to “dissolve” and what appears to be “steam” comes off out of container. | single-displacement reaction | Zn + 2 HCl (aq) --> ZnCl2(aq) + H2(g) | 3. Black smoke occurs | decomposition reactions | 2 (H2O2)(aq) MnO2 2 (H2O) + (O2) | 4. reddish-brown deposit
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Endothermic and Exothermic reactions A chemical reaction is a process in which one or more substances are chemically changed into one or more new substances. A chemical reaction may involve the motion of electrons in the forming and breaking of chemical bonds. Therefore when a chemical reaction takes place‚ energy is transferred to‚ or from‚ the environment. A Chemical reaction can either be exothermic or endothermic. Exothermic Reactions During an Exothermic Reaction a transfer of energy to the
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In the lab testing the heat of a reaction to understand changes in enthalpy in an exothermic reaction‚ the group hypothesized that if the amount of reactant is changed then the amount of heat produced (exothermic) will increase. This hypothesis was supported through the data as each of the six trials produced heat and the larger the piece of magnesium the larger the change in heat was. In the first trial the group had .085 grams of Mg and after being placed in 3 ml of 21.8℃ HCl the temperature of
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Social reaction theory is also commonly called as Labelling Theory . And I agree with this theory . Labelling theory is the theory of how the self-identity and behaviour of individuals may be determined or influenced by the terms used to describe or classify them . It is associated with the concepts of self-fulfilling prophecy and stereotyping . Labelling theory holds that deviance is not inherent to an act ‚ but instead focuses on
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ON THE RATE OF REACTION Aim To study the effect that temperature and concentration of iodide ion solution have on the rate of iodide ion I⁻ oxidation by peroxodisulphate ion S₂O₈⁻‚ creating an iodine clock reaction. Introduction I decided to choose as the topic for my investigation the rate of reaction for its vital importance in the human body. Indeed I am really interested in Biology and especially physiology and I would like to study medicine. The rate at which different reactions happens in the
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There are two types of chemical reaction that occur one goes only in one direction and the other one is reversible. A reversible reaction is when a products starts to form the backward reaction starts where the products turns back to reactant molecules. When the rate of forward and backward reaction is already equal and the concentrations of the reactants and products no longer change with time we can say that chemical equilibrium is already achieved. A reaction is said to be at equilibrium when
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for the organisms by catalyzing various biochemical reactions. Most of these chemical reactions would not take place in the conditions available if the enzymes were not a present. Therefore‚ we can say that being involved as catalysts is the main and most important role of an enzyme in any organism. Furthermore‚ many reactions that are thermodynamically favored do not occur quickly because there is not enough energy necessary to start the reaction (1). This energy is called the activation energy and
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This lab focused on three factors affecting reaction rates‚ temperature‚ surface area‚ and concentration. Our first experiment (table 1) looked mainly into the effects of temperature on the reaction rate. To see how different temperatures would change the reaction rates we had three flasks all containing varying temperatures of water(H20). One with cold water (4°C)‚ one room temperature (21°C)‚ and one with hot water (44°C). In each flask‚ we dropped one tablet of Alka-Seltzer‚ all within 0.008 grams
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objective: In this experiment‚ I decided to find out how temperature would affect endothermic reactions compared to exothermic reactions. An endothermic reaction absorbs energy in the form of heat. This reaction feels cold because it is taking heat away from its surroundings. It also releases gases. An exothermic reaction is a reaction that releases energy as heat. Since the energy is released‚ the exothermic reactions feel hot. Methods/Materials I did three experiments. I mixed lemon juice and baking
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AP Chem Exam - ‘98 1. Solve the following problem related to the solubility equilibria of some metal hydroxides in aqueous solution. (a) The solubility of Cu(OH)2(s) is 1.72 x10–6 g/100. mL of solution at 25° C. (i) Write the balanced chemical equation for the dissociation of Cu(OH)2(s) in aqueous solution. Cu(OH)2 Cu 2+ + 2 OH – (ii) Calculate the solubility (in mol/L) of Cu(OH)2 at 25 °C. (1.72 x10–6 g/0.100 L)(1 mol/97.5 g) = 1.76 x10–7 mol/L (iii) Calculate
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