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
Premium Thermodynamics
Mahathir Mohamad’s Speech About the Democracy in the Philippines -A Reaction Paper- In Mahathir’s speech about the Filipino-style democracy‚ I have to agree with what he had said; “When people think only of the freedoms of democracy and know nothing of the implied responsibilities‚ democracy will not bring the goodness that it promises. Instead it will result only in instability and instability will not permit development to take place and the people to enjoy the benefits of freedom and the
Premium Democracy Political philosophy Government
Abstract “Reaction Time” is the interval of time between the application of a stimulus and the detection of a response and has been thought to differ based upon the effects of modality and warning signals. In the “Reaction Time” experiment a total of 24 students from the University of Cincinnati participated in an experiment consisting of two sensory modalities‚ audition and vision‚ which were combined with two levels of warning signal status. The two levels of warning signal status were signal
Premium Sensory system Computer
Abstract This experiment is to study the effect of temperature on the rate of reaction between potassium permanganate with oxalic acid. We used 2cm3 of 0.02M potassium permanganate and 4cm3 of 1M sulphuric acid into a test tube. In another test tube‚ we placed 2cm3 of oxalic acid. We placed the test tubes in a water bath at 40‚ 45‚ 50‚ 55 and 60oC respectively. When the solutions have attained these temperatures pour the oxalic acid into the acidified permanganate solution and recorded the time
Premium Chemical kinetics Reaction rate Chemical reaction
Redox Reactions Reactions involving oxidation and reduction processes are very important in our everyday world. They make batteries work and cause metals to corrode (or help to prevent their corrosion). They enable us to obtain heat by burning fuels--in factories and in our bodies. Many redox reactions are complex. However‚ combustion and synthesis (from elements) are two ordinary examples which require very little description. Just a little more involved are the displacement reactions‚ with
Premium Chlorine Hydrogen Bromine
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
Premium Carbonyl Aldehyde
Title Experiment 17 Reaction Kinetics- Determination of the Activation Energy of the Reaction Between Oxalic Acid and Potassium Permanganate. Objective To determine the activation energy of the reaction between oxalic acid and potassium permanganate. Theory and Background Activation energy is the minimum amount of energy that is required to activate atoms or molecules to a condition in which they can undergo chemical transformation or physical transport. In terms of the transition-state
Free Chemical kinetics Chemical reaction Reaction rate
BIOL2220 Lab 3: Hill Reaction Introduction In 1937‚ Robert Hill discovered that isolated chloroplasts can generate oxygen when they are illuminated in the presence of a suitable electron acceptor‚ even in the absence of carbon dioxide. This finding was a landmark in the study of photosynthesis because it established that the source of the electrons used in the light reactions is water. It also confirmed that the released oxygen is derived from water instead of carbon dioxide. In chloroplasts
Premium Photosynthesis
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
Premium Hydrochloric acid Hydrogen Chlorine
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
Premium Color Stanford prison experiment Experiment