KS3+Rates+of+reaction


 * Chemical reaction **

Bang, Bubbles & Burning

 * New Words**

Chemical reaction - when two substances join together ( or break apart) to make a new substance. In a chemical rection, the substances thaat undergo a chemical change are called the__ reactants __. The substances that result from the change are called the __ products __.

Observation - what we see when we carefully look at a reaction.

Reversible - when a reaction can go back to where we started with the first chemicals. Irreversible reactions cannot go back to the start

Physical change - when water turns to ice there is no chemical reaction, it is a physical change.

Hoffman Voltameter

Recognize that reactions take place at different rates. RATE OF REACTION = Amount of reactant used / Time RATE OF REACTION = Amount of product made / Time RATE OF REACTION = Volume of gas produced / Time
 * C13. Rate of Reaction **

//* Draw a labelled diagram or identify and define at least 5 key points for number 1 to 4 then complete number 5 (test).//
 * 1) [|Rates of Reaction (Video)]
 * 2) [|Rates of Reaction 1 (Theory)]
 * 3) [|Rate of Reaction 2 (Theory)]
 * 4) [|Changing the Rate of Reaction (Theory)]
 * 5) [|Rates of Reaction (Test)]

Compare the rates of reaction of some metals with oxygen. Compare the rates of reaction of some metals with water. Compare the rates of reaction of some metals with dilute acid. 1. Show how rate of reaction depends on concentration of reactants. 2. Show how rate of reaction depends on temperature. 3. Show how rate of reaction depends on particle size. Remember what you change will determine the value of your results (the rate of reaction).
 * Filtering marble chips using a filter funnel**

//Q1: Why did all the chips added at first dissolve?// It is because there was an excess of acid to take part in the reaction. //Q2: Why did some of the chips added later not dissolve?// All the acid had been used up. //Q3. Why were the contents of the flask filtered?// To remove the solid from the liquid. =* Rate of reaction lab design= __The effect of temperature on reaction rate __ **Aim:** To investigate the effect of temperature on the rate of reaction between sodium thiosulfate and hydrochloric acid.


 * Safety**: Wear eye protection. Do not to inhale fumes.

 1. Put 10 cm3 of sodium thiosulfate solution and 40 cm3of water into a conical flask. Measure 5 cm3of dilute hydrochloric acid in a small measuring cylinder.
 * Hypothesis**
 * Variables**
 * Apparatus**
 * Diagram**
 * Procedure**

 2. Warm the thiosulfate solution in the flask if necessary to bring it to the required temperature. The object is to repeat the experiment five times with temperatures in the range 15–65 °C.

 3. Put the conical flask over a piece of paper with a cross drawn on it.

 4. Add the acid and start the clock. Swirl the flask to mix the solutions and place it on a piece of white paper marked with a cross. Take the initial temperature of the mixture.

 5. Look down at the cross from above. When the cross disappears, stop the clock and note the time taken. Record the final temperature of the mixture in the flask.

 6. As soon as possible, pour the solution down the sink (in the fume cupboard if possible) and wash away.

**Results:** Record your results in the table. Questions to think of:  1. For each set of results, calculate the value of 1/time. (This value can be taken as a measure of the rate of reaction for this experiment).  2. Plot a graph of 1/time on the vertical (y) axis and average temperature on the horizontal (x) axis.
 * ** Initial temperature of the mixture in the flask [°C] ** || ** Final temperature of the mixture in the flask [°C] ** || ** Average temperature of the mixture in the flask [°C] ** || ** Time taken for the cross to disappear [s] ** || **<span style="font-family: &#39;Comic Sans MS&#39;;"> 1/time taken [s ** –1 **<span style="font-family: &#39;Comic Sans MS&#39;;">] ** ||
 * Graph/Data analysis**
 * Graph/Data analysis**
 * Evaluation**
 * Conclusion**

[|Rate of reaction activity] from BBC bitesize
 * [|Rate of reaction] from middleschoolchemistry.com **

Thank to Mr. Benton for sharing the original copy of this pptx! Reaction with metals. = ASSESSMENT Year 9 Date: 17th Feb. 2017 Rate of reaction lab design assessment.= Please wear a lab coat and ** sit down with your partner ** and read the procedure in each paper carefully that is placed on the desk. You and your partner will share the same results that are collected today. You need to plot a graph using the results and then write down your own discussion, evaluation and conclusion based on data analysis. **For 'Discussion (Q1 and Q2) and Evaluation(Q3)': Questions you need to think** (a) If your answer is YES, calculate the average from your trials and plot a graph using the average. (b) If your answer is NO, describe how you can improve your method.
 * * ** Aim: ** To investigate the effect of concentration of an acid on the rate of reaction( magnesium and hydrochloric acid).
 * ** Safety **
 * ** Hypothesis **
 * ** Variables **
 * ** Apparatus **
 * ** Diagram **
 * ** Procedure **
 * ** Results table ** ||
 * * **Results**
 * **[|Graph] from chemicalblog.co.uk**
 * **Discussion/Data analysis**
 * **Evaluation and** **Conclusion** ||
 * Q1**. What did you do to make your test reliable? Have you done your experiment many times? How many trials did you make?


 * Q2.** Describe the pattern(s) / trend of your graph.

Hint: Have you controlled your " Controlled variables" correctly? (a) If your answer is YES, explain 'what you have done well' in this experiment. (b) If your answer is NO, describe what went wrong and what you should have done with a reason'. Thank to Mr. Benton for sharing the original copy of this pptx! Reaction with metals. || Investigation original booklet || Design of investigation part A || Analysis and data process part B || Samples from students
 * Q3.** Is your experiment fair?
 * [[file:9. More About Chemical Reactions.pptx]] || [[file:Year 9 Science - Unit 9 - Rate of Reaction Investigation - 20.01.14.docx]] || [[file:Year 9 Science - Unit 9 - Rate of Reaction Investigation Part A - 23.01.18.docx]] || [[file:Year 9 Science - Unit 9 - Rate of Reaction Investigation Pard B - 23.01.18.docx]] ||
 * With more supports and details.
 * [[file:Safety and data collection.pdf]] || [[file:Discussion.pdf]] || [[file:Evaluation.pdf]] || [[file:Conclusion.pdf]] ||
 * Safety and data table || Discussion || Evaluation || Conclusion ||

Show how rate of reaction depends on the presence of a catalyst. State that enzymes are biological catalysts. Give an explanation (kinetic theory) of the effects of concentration, particle size temperature and catalysts on the rate of a reaction. **Aim:** To investigate the effect of a catalyst to the rate of reaction Catalyst : a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change. Hydrogen peroxide, 20%, 20 mL Sodium iodide solution, 2M, 5 mL Liquidsoap, 1 mL Measuring cylinder, each 100 mL and 10 mL Basin, Food colouring
 * Decomposition of hydrogen peroxide **
 * Hypothesis** q// uestion: //__// Can another substance catalyse the decomposition of hydrogen peroxide? //__
 * Safety: Hydrogen peroxide will act as an oxidizing agent with practically any substance. This substance is severely corrosive to the skin, eyes, and respiratory tract; a very strong oxidant: and a dangerous fire and explosion risk. Wear chemical resistant gloves and goggles when handling 20% hydrogen peroxide. Contact with skin may cause burns. Do not heat this substance. Sodium iodide is slightly toxic by ingestion. Although the liquid soap is considered non-hazardous, do not ingest the material. Do not stand over the reaction; steam and oxygen are produced quickly. Wear appropriate chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. This activity requires the use of hazardous components and has the potential for hazardous reactions. ||
 * Apparatus: **

1. Place a 100 mL measuring cylinder in a basin that is several inches deep. 2. Measure out 20 mL of the 20% hydrogen peroxide into the 100 mL measuring cylinder. 3. Measure out 10 mL of liquid soap into the 10 mL measuring cylinder and add it to the cylinder containing the hydrogen peroxide. Add a few drops of food colouring. 4. Observe if any reaction occurs. 5. Measure out 5 mL of sodium iodide solution using the 10 mL measuring cylinder. Quickly and carefully, add the sodium iodide solution to the 100 mL measuring cylinder. 6. Step back and record the observation.
 * Procedure**

Chemical equation: 2H 2 O 2 (aq) -> 2H 2 O + O 2
 * Results:**

The chemical reaction behind is the decomposition of hydrogen peroxide. Refer to the following equation and answer the questions below. 1. What clues did you have that a chemical reaction occurred in this activity? 2. What is the catalyst in this activity? 3. What evidence do you have that hydrogen peroxide decomposed faster when you added sodium iodide solution? 4. When writing the chemical equation for this reaction, should the catalyst be included on the product side of the chemical equation? 5. If the catalyst is involved in the chemical reaction, why isn't it included as a product in the chemical equation? 6. Which new substances are created when hydrogen peroxide decomposes? 7. What happened to the temperature of the hydrogen peroxide when the catalyst was added? What do we call this type of reaction? What did you think caused this temperature change?
 * Analysis questions:**

**Discussion**: (Analysis) This demonstration evolves a good deal of heat as presented by the steam coming off of the foam as it is produced. The reaction is exothermic. The action of a catalyst is demonstrated. The catalyst is the I - (aq) ion which speeds up the decomposition of the hydrogen peroxide. The decomposition of hydrogen peroxide produces steam and oxygen gas. The oxygen gas and water vapour cause the liquid soap to foam.
 * Conclusion**

media type="youtube" key="FiwpSUHyGOI" width="420" height="315" [|Decomposition of H2O2] from depts.washington.edu

[|Investigating an enzyme-controlled reaction: catalase and hydrogen peroxide concentration] from www.nuffieldfoundation.org

Oxidation: The process of oxidizing; the addition of oxygen. A reaction when a substance burns in air with reaction of oxygen. Combustion: A chemical change, especially o xidation, accompanied by the production of heat and light. A chemical reaction in which a substance, usually a fuel, takes part in a fast reaction with oxygen to release heat energy. fuel + oxygen >> carbon dioxide + water Rusting: The formation of reddish-brown flake of rust(ferric oxides) on iron by oxidation in the presence of water. It is exothermic reaction but as the reaction is slow the heat is produced in small amounts. Iron + oxygen >> iron oxide When water vapour in the air condenses on iron/steel, it makes film on the surface of the metal. Oxygen dissolves in the water and reacts with the metal to form iron oxide. Burning: A process in which a substance reacts with oxygen to give heat and light and a flame develops in the reaction. Respiration: The process in which energy is released from food and produce carbon dioxide and water. glucose + oxygen >> carbon dioxide + water Oxidation occurs in respiration where the carbon in glucose is oxidised to carbon dioxide. Physical change: A change in size/shape or reversible reaction without a change in chemical composition. Chemical change: A process in which one or more substances are changed by the atomic and molecular composition into others. Many chemical reactions are non-reversible changes. reactant: A substance that participates in a chemical reaction, esp a substance that is present at the start of the reaction. product: A substance that is formed/resulting from a chemical reaction. Combination: A chemical reaction of two or more c ompounds, usually to form one other compound Catalyst A substance that can help the reactants in a chemical reaction react with each other faster and that is **not** actually become part of the products of the reaction. Decomposition: Separation of a substance into two or more substances that may d iffer from each other and from the original substance Explosion: A violent release of energy such as heat and light resulting from a rapid chemical or nuclear reaction If coal dust is hot and heated, it produces a flame and explodes in air. The heat produced by this fast reaction causes the air to expand rapidly.
 * Key words for reactions: **

Combustion vs oxidation media type="youtube" key="gatDV2lBdEk" width="336" height="251" Practical Rate of reaction Thank to Mr. Benton for sharing the original copy of this document.