Students’ Conceptual Understanding of Stoichiometry. Introduction Stoichiometry is one of the major concepts in chemistry. Conceptual understanding in stoichiometry is crucial for any student taking chemistry as a subject as many areas in chemistry are highly related to this conceptual understanding. Many previous researches found out that students poses a very low conceptual understanding and they also poses many alternative conception related to stoichiometry. Dahsah. C; Coll. R. K (2007)‚ found
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rate of reaction (mol dm-3 s-1) for the following chemical reaction: CaCO3(s) + HCl(aq) CaCl2(s) + H2O(l) + CO2(g) Research question: How does altering concentration (mol dm-3) of hydrochloric acid (HCl) affect the rate of reaction (g/s) for the following reaction: CaCO3(s) + HCl(aq) CaCl2(s) + H2O(l) + CO2(g) Background information: The reaction between calcium carbonate and hydrochloric acid is an example of a neutralization reaction between an acid and a base. Neutralization reactions involve
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dioxide and water vapor. In the balanced equation for this reaction‚ what are the coefficients of butane‚ oxygen‚ carbon dioxide‚ and water‚ respectively? Question 1 options: 2‚ 13‚ 4‚ 10 1‚ 6‚ 4‚ 5 1‚ 6‚ 8‚ 10 1‚ 13‚ 4‚ 5 2‚ 13‚ 8‚ 10 Save Question 2 (2.7 points) When aluminum metal is dissolved in perchloric acid‚ aluminum(III) perchlorate and hydrogen gas are formed. In the balanced equation for this reaction‚ what is the coefficient of hydrogen gas? Question 2 options:
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Reaction on Reaction Paper The first thing that came to my mind when I have heard about Reaction paper is “What exactly is it?” and before I get an understanding of that‚ I resisted that change. But later‚ when I have studied about it and understood its purpose‚ I have started thinking “Why people avoid change at the first look without an analysis?” The general human tendency is to live in a comfortable zone in which he has lived for quite some time. He draws a circle‚ thinks that circle is his
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Week 10: Oxidation and Reduction Reactions: The Reactions of Copper Data: Part I: Preparing a solution of copper (II) nitrate Initial mass of copper wire: .520g Mass of copper wire after vigorously scouring: .518g Observations of Copper (II) ribbon mixed with HNO3: Solution turned green. Thick brown gas formed. Copper (II) bubbled vigorously. Cu (II) dissolved‚ solution appeared green/blue. After the addition of H2O a blue crusty precipitate formed. Part II: Synthesis of solid copper
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Double Replacement Precipitation Reactions Determine whether an ionic double replacement reaction has occurred.If I place different amounts of ionic solutions in a well plate‚ then I will be able to determine which of the solutions has had an ionic double reaction placement because I will use the solubility rules to decide which product produced the solid precipitate.Place five drops of silver nitrate into well A1 through A4. Place five drops of Iron (III) Nitrate into rows B1 through B4. Place
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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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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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REACTIONS OF HYDROCARBONS Vanessa P. Manibpel De La Salle University - Dasmariñas ABSTRACT Five substances namely Hexane‚ Eugenol‚ Unknown hydrocarbon 1‚ Unknown hydrocarbon 2‚ and Acetylene gas was used for the selective reactivity of hydrocarbons to functional group tests; Bayer’s test‚ Bromine test light‚ Bromine test dark‚ and Tollen’s test. In Bayer’s test‚ only Acetylene‚ Eugenol and Unknown hydrocarbon 2 reacted positively and the rest retain the purplish color of KMnO4. On the other hand
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Chapter 1 Chemical Reactions and Equations Q.1. Why should magnesium ribbon be cleaned before burning in air ? Ans: Magnesium ribbon is a very reactive metal. When stored it reacts with oxygen to form a layer of magnesium oxide on its surface. This layer of magnesium oxide being a stable compound prevents further reaction of magnesium with oxygen. The magnesium is cleaned before burning in air to remove this layer so that the metal can be exposed to air properly. Q.2. Write the balanced
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