Properties of Chemical Reactions
Ms. Whitty, Science 10
Fiona Adams, November 1st, 2012
Introduction
Chemical reactions are a part of our daily lives, from rusting metal to making bread to leaves changing colour in the fall. A chemical reaction is the process that occurs when two or more substances combine to produce a chemical change. When a chemical reaction takes place, the change is indicated by one or more qualitative properties. The colour or odor could change, gas could be produced, a precipitate – a solid substance in a solution - could be formed, or energy could be absorbed or released. The substances initially involved in a chemical reaction are called reactants. When chemical reactions occur, the end result is called a
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The acetic acid was clear, colorless and in a liquid state. The sodium bicarbonate, however, was a white powder, in a solid state. The reaction caused the new substance to bubble and foam, producing a gas.
(Table 4) Quantitative Observations from Part 2 - Mass of Sodium Bicarbonate (g) | 1.01 | Mass of Acetic Acid (g) | 14.29 | Mass of Products (g) | 14.88 |
Analysis
Part 1:
The chemical reaction that took place was evidenced by several qualitative observations. The colour of the two original substances was clear, and when combined the colour changed to yellow – a change of colour is clear evidence of a chemical reaction. The word equation for this reaction would be - potassium iodide + lead (II) nitrate Potassium nitrate and lead (II) iodide. In the form of a balanced equation, this reaction would be - 2KI + Pb(NO3)2 2KNO3 + PbI2.
Weighing both the reactants and the product showed that the mass of the reactants, with the apparatus, was 140.26 grams. The mass of the product, with the apparatus, was also 140.26 grams – the product of this reaction had the same mass as the reactants. These results were expected, based on the Law of Conservation of Mass. The Law of Conservation of Mass is neither created nor destroyed in a chemical reaction. The application of the Law of Conservation of Mass means that the mass of products in a chemical reaction will equal the mass of the
There was an assortment of different changes indicating that chemical changes were taking place such as change in color or chemicals bubbling when combined with another chemical.
In any chemical reaction, the mass of the products is less than the mass of the reactants.
When combined Sodium Bicarbonate and Hydrochloric Acid, Carbon Dioxide is produced. The two chemicals do not undergo a change in color but a chemical change when CO2 is produced.
The objective of the experiment was to observe different reactions with different chemicals. The experiments emphasized on the chemical changes occurring in acids and bases as well as color changes and bubble formations. The experiments allowed for a better understanding of the undergoing chemical changes in mixtures. Some mixtures instantly changed colors while others were transparent or foggy. Some mixtures produced thick color that created solids called precipitates. Mixtures KI + Pb(NO3)2 and NaOH + AgNO3 both produce noticeable precipitates after a while. It was interesting to see the different acidic and base reactions like the fuchsia color formation in NaOH + phenolphthalein.
A chemical reaction is a process that involves change of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction. The key concepts of a chemical reaction are:
| NaHCO₃ reacts with the hydrochloric acid by heating up violently, bubbling, dissolves, and new gas formation
This is a chemical change because a new color is created and it is exciting the electrons. Burning is a chemical reaction because there is a new substance being created. There is also a color change and that is another way to tell that it was a chemical reaction. A new substance was made this is why it was a chemical change. If you take ice for example and melt it turns into a liquid. This is not a chemical change because it is still water just in a different form nothing new is created. Unlike when the salt solutions are burned and something totally new is created/
One type of chemical reaction, called combustion, involves the burning of various compounds and elements. Some substances are more
Write a balanced chemical equation for each reaction #1-8. Classify each reaction using the information provided in the
What is the appearance of reactant, Evidence of chemical reaction, and properties of a product?
3. The “new” substances that were formed as a result of chemical change were many. When I took the candle and lit it, it burnt and formed smoke. When I took the wooden split and lit the paper on fire, the color around the green paper changed to be brown, burnt and changed into ashes. Also, I poured Hydrochloric acid and magnesium ribbon in a test tube and it started bubbling and it heated up in the bottom.
The solution of the formed ash and the water is basic, which was shown using the pH paper where its color became blue. A chemical change occurred. It is described using the following chemical reaction:
A reaction occurs when a substance is added to this chemical gel and there is a color change. The color produced should help you to determine the type of substance in the sample, by using the color chart.
A chemical reaction is when substances (reactants) change into other substances (products). The five general types of chemical reactions are synthesis (also known as direct combination), decomposition, single replacement (also known as single displacement), double replacement (also known as double displacement), and combustion. In this lab, the five general types of chemical reactions were conducted and observations were taken before, during, and after the reaction. Then the reactants and observations were used to determine the products to form a balanced chemical equation. The purpose of this lab was to learn and answer the question: How can observations be used to determine the identity of substances produced in a chemical reaction?
A chemical reaction is a process in which elements or compounds react with one another to create new or different substances. There are two parts to a reaction. Those two parts are the products and the reactants. The reactants are the chemicals or chemical compounds that are going through the reaction itself. The products are chemical elements or chemical compounds that are produced as a result of the reactant or reactants reacting. There are four key indications that there’s a chemical reaction is taking place. Those four signs include a change in color and/or odor, formation of a precipitate or a gas, the release or absorption of energy (light, heat, electricity), and if the reaction is irreversible. Along with this information, there are ways to predict the products of a reaction.