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# GCSE: Patterns of Behaviour

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1. ## To Find Out How Much Surface Area Affects the Rate of a Reaction Between a Potassium Tablet (K2co3) and Hydrochloric Acid (Hcl).

I think this because there is more K2CO3 for the HCl to collide with. Diagram Plan First you must add water to a basin (enough to put an upside-down 250 ml measuring cylinder in), fill a 250 ml measuring cylinder and place it upside-down in the basin and keep it off the bottom by a clamp. You must then add 30 ml of HCl to a conical flask, then place a K2CO3 tablet to it, place a bung with a tube coming out of the top and going into the basin and into the measuring cylinder, you must time the experiment for 3 mins.

• Word count: 510
2. ## Investigating the Rate of Reaction From the Concentration of Hydrochloric Acid On Calcium Carbonate.

Catalysts: When a catalyst is used the reaction will be faster/slower. A catalyst is a substance that changes the rate of reaction, slower or faster, without taking part in the reaction by changing itself. The speed of the change in reaction rate is dependent on what catalyst is used. 4) Concentration: The higher the concentration the quicker the reaction. The lower the concentration the slower the reaction. A higher concentration of a substance means there are more particles in the same volume of space so there are more collisions, this increases the rate of reaction.

• Word count: 1467
3. ## Lab Report: How the temperature of water will affect the reaction time of sodium thiosulfate and hydrochloric acid

Draw an 'x' on three pieces of papers 4. Add 100 ml of 10degrees water to a beaker. If the tap water is not cold enough add some ice to the beaker to decrease the temperature. 5. Measure 10 ml of Sodium Thiosulfate and add this into a flask. 6. Put the flask into the beaker containing water 7.Measure 5ml of Hydrochloric Acid and pour that into the flask containing the Sodium Thiosulfate. 8.Make sure to have a piece of paper with an 'x' underneath the beaker. 9. Record your results on your results table 10.Repeat steps 4 to 9 two more times, then calculate your average for that temperature.

• Word count: 848
4. ## Making Salts Methods

Therefore, the problem can be overcome by adding a third chemical into the reaction mixture called an indicator. Indicators are chemicals that change colour with a change in ph. The indicator is added to the acid and as the soluble base is added, the pH of the solution is raised until all the acid has reacted (been neutralized). The experiment can be run a number of times to gain a more accurate average value for the volume of base that needs to be added to neutralise the acid used.

• Word count: 594
5. ## Experiment Plan. How much energy is transferred as heat when acids react with alkalis?

All pure acids are mineral acids. Throughout the group of acids, they all show some common properties. The common properties are: they?re corrosive to metal and skin, they turn litmus paper red, they have a pH of less than 7, they contain H+ ions and they?ll donate these during a reaction. What are alkalis? An alkali is a chemical compound that neutralizes or effervesces with acids and turns litmus blue. They are sold as tablets to treat things such as heartburn, as they neutralise the acid. Common alkalis include sodium hydroxide, potassium hydroxide and calcium hydroxide. They are identified in the same way as acids are ? by using a pH scale and litmus paper.

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6. ## How does the concentration of HCl affect the rate of reaction with CaCO3?

Collision theory explains why chemical reactions occur and why they react at different rates. It was proposed by Max Trautz and William Lewis in 1916 and 1918. A reaction can only take place if the reactant particles collide; also the force in which they collide has to be stronger than the bonds of the reactant particles. The activations energy (energy required for a reaction) has to be stronger than the bonds so that they break the bonds and form new one to make new particles (products). Chemical reactions can either be successful or unsuccessful, successful chemical reactions only take place when successful collisions happen; successful collision only happens when the activation energy is stronger than the bonds.

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7. ## Rate of Reaction - Formation of Sulfur

Swirl the flask twice (controlled variable) and place it over a piece of white paper with a thick, black cross marked on it. 4. Look vertically down onto the cross and record the time taken (in seconds) for the cross to disappear. The time taken for the cross to disappear is the dependent variable. 5. Place 40mL of prepared sodium thiosulfate solution in a 250mL conical flask and add 10mL of distilled water. Total volume is 50mL. 6. Repeat steps 2-4 using the same cross (controlled variable).

• Word count: 1830
8. ## Investigating how the concentration of acid affects the rate of reaction between hydrochloric acid and calcium carbonate (marble chips)

Here is the balanced equation for this reaction: CaCO3(S) + 2HCl (aq) CaCl2 (aq) + H2O (L) + CO2 (G) Control Variables: I will keep the temperature constant by keeping the equipment in the same environment before and during the practical. I will carry out the experiment in a specific classroom. The surface area, size and mass of the marble chips will be fairly constant. The marble chips will be measured out using weighing scales correct to 2 decimal places. The volume of HCl used will be kept constant.

• Word count: 3041
9. ## Hypothesis - I am going to be examining how much energy is transferred as heat when acids react with alkalis, also known as the heat of neutralisation.

Sulphurous acid 7. Citric acid What are alkalis? An alkali is a base that is soluble in water. An alkali is a basic, ionic salt of an alkali metal or alkali earth metal element. Alkalis are best known for being bases (compounds with pH greater than 7) that dissolve in water. Examples of alkalis 1. Sodium hydroxide - NaOH 2. Calcium hydroxide - Ca(OH)2 3. Potassium hydroxide - KOH Neutralisation When an alkali is added to an acid, the pH of the mixture rises as the alkali reacts with it forming neutral products. An acid added to an alkali causes the pH to fall because the alkali is removed by reaction with the acid.

• Word count: 660
10. ## Investigating the rate of reaction between hydrochloric acid and calcium carbonate

increase in the rate of reaction.Increasing the concentration of acid molecules increases the frequency or chance at which they hit the surface of calcium carbonate to dissolve them. The effect of Pressure If one or more of the reactants is a gas then increasing pressure will effectively increase the concentration of the reactant molecules and speed up the reaction. The effect of Surface Area If a solid, reactant or a solid catalyst is broken down into smaller pieces the rate of reaction increases.

• Word count: 6193
11. ## History of the Periodic Table

Brand kept his discovery a secret until 1680 when Robert Boyle rediscovered it and it became public. Due to the publicity, many questions were raised as what it means for a substance to be classified as an element. Boyle later defined an element as a substance that cannot be broken down into a simpler substance by a chemical reaction. This simple definition severed for nearly 300 years until the development of the notion of subatomic particles. In 1789, a book named Elementary Treatise of Chemistry was published by Antoine-Laurent de Lavoisier and was considered to be the first modern chemical textbook.

• Word count: 675
12. ## An Investigation: Factors That Affect The Rate Of Reaction between Calcium carbonate and Hydrochloric Acid

+ H2O (l) + CO2 (g) In this reaction, carbon dioxide is the easiest substance to measure. This is because it is the only gas in the reaction. It bubbles off, and can be collected in a gas syringe, where its volume is being measured. Other reasons why the reaction is right, is that we can change the surface area of the calcium carbonate, and change the concentration by changing the hydrochloric acid. By changing these two factors, we can see how fast these reactions take place. If a reaction is too fast, it will become too difficult to read, such as a firework exploding.

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13. ## How Does The Concentration Of Sodium Thiosulfate Affect The Rate Of This Reaction?

Changing the concentration of the acid does not change how quickly the particles are moving (i.e. it doesn't increase the amount of energy they have.) Temperature: When we increase the temperature at which a reaction is taking place, the particles move more quickly. At a lower temperature, the number of collisions is lower because the particles are moving more slowly. Also when a collision occurs, there is less chance of a reaction taking place because the movement energy in the particles is less. At a higher temperature, the number of collisions is greater because the particles are moving more quickly.

• Word count: 5155