How does changing the Concentration of Hydrochloric Acid Affect the Rate of Reaction between Hydrochloric Acid and Magnesium? Dependent Variable Volume of Hydrogen Produced - the volume of hydrogen produced in cm3 will be affected by the independent variable which in this case is the concentration of the hydrochloric acid. There is no way in which the volume of hydrogen produced can be controlled however make sure none is lost by making sure that the gas syringe is correctly connected. Measurements will be taken every 30 seconds for the volume of hydrogen produced for 5 minutes. Independent Variable Concentration - the variable which will be controlled is the concentration of the hydrochloric acid. The concentrations which will be used are 2M, 1.8M, 1.6M, 1.4M, 1.2M, 1.0M, 0.8M, 0.6M, 0.4M and 0.2M. The concentrations will be changed by using different measurements of hydrochloric acid and water. Controlled Variable The equation for the reaction can be seen below; Mg(s) + 2HCl(aq) --> MgCl2(aq) + H2(g) I will be controlling many of the variable which affect the volume of hydrogen which is produced. Temperature - The temperature will be controlled because if the temperature was to be changed this could affect the dependent variable. To control this the experiment shall be done in the same lab with no heating and no cooling will be done while the temperature will also
The effetct of copper nitrate on the germination of mustard seeds. Aim The aim of the experiment is to investigate the effect of diferent concentrations of copper nitrate upon the growth of germinating mustard seeds. Introduction A seed is an embryo plant and contains within itself all the materials and energy to start off a new plant. germination is started by the rapid uptake of water by the seed resulting in a dramatic increase in mass. although copper is generally an environmental hazard to humans only in regions surrounding mine sites and smelters, it also causes significant crop losses when it accumulates in soil where it is used as a fungicide. plants prevent damage from excess accumulation of the essential nutrient copper by means of internal and root surface mechanisms. most of the functions of copper as a plant nutrient are based on the participation of enzymatically bound copper in redox reactions. some plants growing on mine spoil heaps, which have resistent strains to toxic metal, have caused the plants to have the ability to transport copper out of the cell into the cell wall, so that it has less effect on cell metabolism. these copper tolerant grasses have evolved due to selection pressuresbeing placed on the plants, which has inturn led those who are better adapted, copper tollerant, to survive providing them with a selective advantage. Prediction
Heat of Neutralisation - I am going to investigate the heat of neutralisation between acids and alkalis.
Heat of Neutralisation. I am going to investigate the heat of neutralisation between acids and alkalis. Prediction I predict that no matter what strong acid and alkali react together you will always get the same heat of neutralisation because the same reaction is always taking place. E.g. . HCl and NaOH 2. HNO3 and NaOH 3. NO3 and KOH . H++Cl¯+Na+ + OH¯ Na++Cl¯ + H2O H+ + OH¯ H2O 2. H+ + NO3¯+ Na++OH¯ Na+ + NO3¯+ H2O H+ + OH¯ H2O 3. H+ + NO3¯ + K+ + OH¯ K+ + NO3¯ + H2O H++ OH¯ H2O I am also going to react 2 weak acids (ethanoic acid and propanoic acid) with a strong alkali (sodium hydroxide.) I predict that the energy change i.e. the heat of neutralisation will not be same as before because with weak acids and alkalis some energy is required to fully ionise them. Heat of neutralisation is the heat change when an acid and an alkali react together to form 1 mole of water. Fair Test To ensure the investigation is made fair I will always use the same concentration of acid and alkali (1 mole.) The experiments will always be carried out at room temperature so the initial temperature is the same. I will also repeat the experiments to obtain good results, if the results vary in any way I will calculate the average. Apparatus Measuring Cylinders Pipettes Thermometers Polystyrene Cup Safety To ensure the experiments are carried
Alyssa Bellave Living Environment 0/26/11 Mrs. Padilla pH Lab Introduction: Substances, even household substances, can be acidic, basic, or neutral. Acids and bases are called aqueous solutions, or mixtures of certain substances dissolved in water. The amount of acidity or basicity can be measured by using the pH scale. The scale runs from 1-14. The scale has to do with the amount of hydrogen ions [resent in a substance. Hypothesis: Our hypothesis for this experiment consists of twelve different substances. The tomato juice will be acidic; the distilled water will be neutral; the Windex will be basic; the vinegar will be basic; the soda will be basic; the milk will be neutral; the buttermilk will be neutral; the baking soda solutions will be acidic; the "green" cleaner will be basic; the household cleaner will be acidic; the Lemon Juice will be acidic. Materials: For this lab we need pH paper, a spot plate, water (distilled, if available), and substances with varying pH. Safety: In this lab we must were goggles and aprons to avoid skin contact with all chemicals that are going to be used in this experiment. If it does happen, we must report any skin contact or chemical spills to our instructor immediately. Procedure: First we get a spot plate and put three to four drops of each liquid substance in each of the wells. The liquid must correspond
To see how the concentration of acid, reacting with potassium carbonate, affects the rate of reaction
Aim: To see how the concentration of acid, reacting with potassium carbonate, affects the rate of reaction. Intro: This is the reaction I am using in my coursework: 2HCl + K2CO3 CO2 + 2KCL + H2O In order for substances to react together the particles in the substances must collide with each other and the collision must have enough energy. If there isn't enough energy, no reaction occurs. If there are lots of successful collisions then a lot of CO2 will be produced. The rate of a reaction depends on how many successful collisions there are in a given unit of time. A reaction can be made to go slower or faster by changing the concentration of a reactant. Acid particle Water molecule Potassium carbonate tablet 1 2 In dilute acid, there are not so many acid particles (see diagram 1). This means there is not much chance of acid particles hitting a potassium carbonate particle. In a more concentrated solution of acid, there are more acid particles (see diagram 2). There is now more chance of a successful collision occurring. Concentration is how much of a substance there is in a certain volume and is measured in Moles per litre of solution (M). The concentration of a solution is the amount of solute, in grams or Moles that is dissolved in a litre of solution. That is what my coursework is mainly about. I predict that on my
Chemistry Investigation on neutralisation reaction Plan Neutralisation is the reaction that occurs when an acid has its acidity, that is its hydrogen ions removed by, another chemical containing OH- hydroxide ions. Chemicals that can cancel out an acid in this way are: bases (metal oxides or hydroxides), alkalis (bases that dissolve), metals (e.g. magnesium) or metal carbonates (e.g. marble chips) All of these have a similar way of removing the hydrogen from the acids (they swap it or their metal atoms) but the reactions are quite different. They will all get quite hot if the acid is strong enough, but only the last two will make bubbles. Metals form hydrogen gas, carbonates make carbon dioxide. All of them will leave a neutral chemical after the reaction has finished, if all the acid has been used up. Titration is a technique used to calculate the concentrations or amounts of substances. In an acid base titration you may have an acid that you don't know the concentration of, and a base whose concentration you do know. The technique is to measure out accurately a volume of the alkali of unknown concentration into a flask, and fill up a burette with the acid. Add some indicator solution to the acid in the flask, so that when all the acid has reacted with the base, there will be a colour change. The burette is graduated. You then open the tap on the burette and let the acid
Analysis The results of my investigation show that the larger the amount of hydrogen in the acid, the smaller the amount of acid needed to neutralise the alkali. This is because when an acid is added to an alkali each hydrogen ion in the acid joins an hydroxide ion in the alkali to form neutral water. Hydrogen ion from Hydroxide ion from Neutral water acid alkali The solution only becomes neutral if the amount of hydrogen ions and the amount of hydroxide ions are equal. If there were more hydrogen ions than hydroxide ions then once every hydroxide ion joined with 1 hydrogen ion there would be hydrogen ions left meaning the solution would become acidic. If there were more hydroxide ions than hydrogen ions then once every hydrogen ion joined with 1 hydroxide ion there would be hydroxide ions left meaning the solution would become alkaline. When an acid contains more hydrogen then there are a greater number of hydrogen ions per ml than in an acid containing less hydrogen so it will be stronger. For example in sulphuric acid (H2SO4) there would be more hydrogen ions than in the same amount of hydrochloric acid (HCl), twice as many because there are twice as many in the formula. The alkali in my experiment remained the same throughout (NaOH)
The Effect of Concentration on the Rate of Reaction when you React Hydrochloric Acid with Marble Chips
Introduction To observe how concentration affects the rate of reaction I will be doing an experiment involving an acid, hydrochloric acid (HCl) and marble chips, Calcium Carbonate (CaCO3). This experiment requires the following apparatus: * Conical flask * Thistle tube * Rubber stop cork * Delivery tube * Burette * Plastic container In this experiment some factors must be varied and others controlled. The concentration of the acid needs to vary. This is because the experiment involves measuring the affect of concentration on the rate of reaction. The volume of the acid used in the experiment needs to be the same because this will make it a fair test. Preliminary work has shown that 25cm3 of acid is a good amount to use. The mass of marble chips (calcium carbonate) needs to be kept constant. Preliminary work has also shown that an appropriate mass of chips to be used is 1.5 grams. The size of the marble chips must be kept relatively the same because the surface area affects the rate of reaction. It affects the rate of reaction because finer particles cause the surface area to increase as they take up more space than larger chips and therefore the extra surface area leads to a quicker reaction because there are more collisions. Collision theory states that the rate of reaction increases depending on how often and how hard the particles collide with each other in order
Oserving the properties of water. Place a drop of water on a smooth plastic sheet or on the bench. Look at it closely from the side.
SOME OBSERAVATION ON WATER Experiment # 1: Place a drop of water on a smooth plastic sheet or on the bench. Look at it closely from the side. Draw the outline of the drop. How are the molecules held in their place? * The drop of water and the drop of detergent have a different thickness, because the molecules are held differently. The drop of water, in fact, has a higher thickness. The molecules are closed to each other and it's possible to notice the surface that behaves as an elastic membrane that surrounds and compresses the underlying liquid. There is a force of cohesion that determines the surface tension. Experiment #2: Fill a clean 250 ml. beaker with water to about 1 cm. below the top. Carefully float a small filter paper on the surface. Carefully drop a needle, exactly horizontal, on the paper. Wait until the paper becomes soaked and sinks. Observe the needle carefully. After you have observed it, add one drop of detergent with a glass or plastic rod. * the piece of paper floats on the water and then it sinks because it get too wet. the needle continues to float, although its specific gravity is higher than the water's one, maybe because the water surface forms a kind of membrane ( see: ex.#1), impenetrable by small objects (as the needle). Adding the detergent, the needle has sunk because
Introduction I am going to do an investigation on how much acid is needed to neutralise a certain amount of alkali. The acid that I will use is hydrochloric acid and the alkali I will use is sodium hydroxide. Hydrochloric Acid Hydrochloric acid (HCl) contains hydrogen and chlorine and is ionically bonded. Hydrochloric acid looks like this: Sodium Hydroxide Sodium Hydroxide (NaOH) is made up from Sodium, Hydrogen and oxygen. NaOH is ionically bonded and it looks like this: Acids, Alkalis and Neutralisation An acid is a proton donor and an alkali is a proton receiver. An Acid will have a pH less than 7 and an alkali will have a pH of more than 7. An acid with a pH of 1 is the strongest as ALL of the Hydrogen ions are ionised. The strongest alkali, with a pH of 14, is when ALL the hydroxide ions are ionised. Neutralisation is when an acid and an alkali of equal strengths are mixed, the pH will be 7 and salt and water is produced. In more detail it is when ionised hydroxide and hydrogen meet and share electrons. When a substance is diluted the concentration is weakened. The molarity changes when the water is added. The indicator will change colour when neutralisation occurs, also the temperature will stop rising. Choosing an Indicator I will find the best indicators to use in my experiment, the three indicators that I will compare are: Phenol Phtalein Methyl