Types of Chemical Reactions by JOSH BLENKIRON

Acid-Base Reactions - What are they?

josh_blenkiron — 2018-11-19 22:47:41 UTC

Acid-base reactions (a.k.a : Neutralisation reactions) are, as the name implies, caused by the mixture of acids and bases. In case you didn’t know, acids and bases are classified using the pH scale, a scale that goes from zero to fourteen. The substance’s value on the pH scale is based on the number of hydrogen ions present within it (substances below seven being acidic and substances above seven being alkaline). During an acid-base reaction, these two reactants’ acidities cancel each other out, creating salts, water and possibly several other substances of varying acidity.

Acid-Base Reactions - Common reactants and products.

josh_blenkiron — 2018-11-19 23:25:11 UTC

Reactants
As previously stated, acid-base reactions consist of an acid and a base. Here is a list of common acids and bases as well as a short description of each :
Hydrochloric Acid
Chemical Formula - HCl
Acidity (10mM) - 2.04
Appearance - Clear liquid with occasional bubbles.
Sulfuric Acid
Chemical Formula - H₂SO₄Acidity (10mM) - 1.87
Appearance - Clear liquid with occasional bubbles (same as HCl).
Sodium Hydroxide
Chemical Formula - NaOH
Acidity (10mM) - 11.95
Appearance - Slightly transparent white coloured grains.
Calcium Carbonate
Chemical Formula - CaCO₃
Acidity (10mM) - 9.91
Appearance - Opaque white soft-looking powder.

Products
The main products of acid-base reactions are various different salts. Such as common table salt :
Table Salt
Chemical Formula - (NaCl)
Appearance - Slightly transparent white coloure grains (very similar to sodium hydroxide)
Water is also a product of acid-base reactions. Water’s acidity is almost always seven or around seven. This makes it neutral on the pH scale.

Acid-Base Reactions - Reaction example.

josh_blenkiron — 2018-11-19 23:58:43 UTC

An example of an acid-base reaction is the reaction between sodium hydroxide (alkaline) and hydrochloric acid (acidic). The worded equation would look something like this :

Sodium Hydroxide (aq) + Hydrochloric Acid (aq) = Table Salt (aq) + Water (l)

The chemical equation of the same reaction would look something like this :

NaOH (aq) + HCl (aq) = NaCl (aq) + H₂O (l)

As we can see, the OH from NaOH and the H from HCl combine to create H₂O. We also see that the leftover Na from NaOH and Cl from HCl combine to create NaCl.

Acid-Base Reactions - How do you identify an acid-base reaction?

josh_blenkiron — 2018-11-20 01:48:16 UTC

If you know that you are mixing an acid and a base, there is a very high chance that the reaction is a acid-base reaction. If you do not know the acidity of the reactants, however, there are other ways you can tell. For example, the formation of water and salts is a good indication that the reaction that has just occured is an acid-base reaction; as water and salts are some of the main products of acid-base reactions. The release of heat is also a good indicator when it comes to acid-base reactions. There is much evidence pointing towards the fact that acid-base reactions are exothermic such as the sodium hydroxide and hydrochloric acid experiment from earlier, which is both an acid-base reaction and an exothermic reaction. The final indicator is a change in acidity in the products. Since the acid and alkaline neutralise each other, their products will likely be neutral or near-neutral on the pH scale.

Acid-Base Reactions - Reactions in nature.

josh_blenkiron — 2018-11-20 04:03:43 UTC

Composting is an example of acid-base reactions in nature. Fruit from a tree falls to the ground. What isn’t eaten by the fauna decays and is absorbed by the earth. The decaying fruit releases carbon dioxide gas (which is acidic) and can help balance the acidity of the earth if it is too alkaline / contains too many alkaline substances. It is difficult to tell which alkalies could be within the soil that the carbon dioxide gas reacts with, but some research indicates that it is likely lime. The picture below is an example of this reaction in reverse (in a sense).

Photosynthesis - What is it? Common reactants and products.

Ishanns14 — 2018-11-22 03:10:17 UTC

Photosynthesis is the process by which plants and some microorganisms use energy from the sunlight to produce glucose from water and carbon dioxide. There are two types of photosynthesis; oxigenic photosynthesis and anoxigenic photosynthesis. The two types of photosynthesis are very similar, however oxigenic photosynthesis is more common. During oxygenic photosynthesis, light energy transfers electrons from water (H₂O) to carbon dioxide (CO₂), to produce carbohydrates. In this transfer, the CO₂receives electrons, and the water loses electrons. Ultimately, oxygen is produced along with carbohydrates. This process is the direct opposite of respiration. on the other hand, anoxigenic photosynthesis uses electron donors other than water. The process typically occurs in bacteria such as purple bacteria and green sulfur bacteria which are primarily found in various aquatic habitats.

An example of the opposite. An alkali being introduced to acidic soil for the purpose of neutralization.

josh_blenkiron — 2018-11-22 03:25:48 UTC

Photosynthesis - Reaction Example.

Ishanns14 — 2018-11-22 03:27:53 UTC

Oxigenic photosynthesis
6CO₂ + 6H₂O + Light energy → C₆H₁₂O₆ (sugar) + 6O₂This reaction createsoxygen because it uses water as a base reactent.

An oxigenic photosynthesis
CO₂+ 2H₂A + Light Energy → [CH₂O] + 2A + H₂O
This reaction doesn't createsoxygen. The A in the equation is a variable and in H₂A represents any potential donor.

Photosynthesis - How do you identify photosynthesis?

Ishanns14 — 2018-11-22 03:31:35 UTC

Photosynthesis is a process that occurs everyday around us. This process cannot be seen because we cannot see gas. Normally we can’t see the oxygen produced by photosynthesis, but if we place a living plant underwater we ca see bubbles in the water. These float up through the funnel and displace the water in the test tube. This little experiment can be used to see if a plant is conducting photosynthesis. You can also check a plant's leaf's color. If the color is green then photosynthesis is occurring, but if the color is brown then it is not.

Photosynthesis - Reactions in Nature.

Ishanns14 — 2018-11-22 03:32:47 UTC

Photosynthesis occurs naturally in plants and some bacteria. Inside a plant's cells are structures called chloroplasts. It's in these structures where the chlorophyll resides. There are two main phases to the process of photosynthesis. In the first phase, sunlight is captured by the chloroplasts and the energy is stored in a chemical called ATP. In the second phase, the ATP is used to create sugar and organic compounds. These are the foods plants use to live and grow.

Acid-Base Reactions - Who do they affect and how?

josh_blenkiron — 2018-11-22 03:46:36 UTC

There are a lot more acid-base reactions in our day to day lives than you might think. The treatment of insect stings (wasps, bees and ants) is a good example of an acid-base reaction that is fairly common in everyday life.
Wasp stings are alkaline, so using acids can help neutralize the poison. Ant and bee stings on the other hand are acidic, so the use of alkaline substances can help in the neutralization of the poison. Another more common example of acid- base reactions in day to day life would be the process of brushing your teeth. The decay of food particles in our mouths results in the production of acids that cause tooth decay. Because of this, toothpastes will usually use alkaline substances in order to aid in the prevention of tooth decay. So, in short, everyone is affected by acid-base reactions.

Combustion - What is it?

karnik_wadhawan — 2018-11-26 04:07:26 UTC

Chemical reactions requiring oxygen and another substance as a reactant are known as combustion reactions. These reactions are exothermic meaning they release energy as heat and occur due to either flames, fire or explosions. In combustion reactions, oxygen chemically bonds with another reactant to produce an oxidized product.

Types of Combustion

karnik_wadhawan — 2018-11-26 04:08:25 UTC

There can be complete and incomplete combustion reactions. “Clean”(complete) reactions occur when a hydrocarbon (compound of only carbon and hydrogen) is oxidized and thus produces only water (H2O) and carbon dioxide (CO2). An example of this is burning candle wax, where the wick is hot enough to vaporize the wax. This wax reacts with oxygen in the air and produces water and carbon which disperse into the air, until nothing remains. A “dirty” combustion reaction occurs when a hydrocarbon is oxidized but releases additional waste such as additional carbon or/and carbon monoxide. An example of this is the burning of many fossil fuels such as coal which releases both additional carbon and carbon monoxide with water and carbon dioxide.

How to determine whether combustion has occurred?

karnik_wadhawan — 2018-11-26 04:10:42 UTC

In a combustion reaction you would see a flame or explosion. The flame can last for as long as it needs to and the explosion may be really short.
Smoke may be smelt due to constant burning and you usually wouldn’t want to feel this reaction as it is usually very hot and dangerous.
As for hearing, the loud sound of an explosion or the constant squeak of the flame may be heard. Electrical currents may also be heard in specific combustion reactions.

Combustion reactions can be determined by viewing the equation as well since oxygen will always be a reactant.

An example of a worded reaction is Methane + oxygen → carbon dioxide + water
The chemical equation to this is CH4 + 2O2 → CO2 + 2H2O

Combustion in everyday life

karnik_wadhawan — 2018-11-26 04:15:29 UTC

Combustion reactions occur as bush fires and grass fires in nature and can be very dangerous. They are caused in the presence of fuel, oxygen and an ignition source and burn the environment including trees, grass and wildlife.

Bush fires affect almost everyone since they reduce the number of trees hence wood which is used very commonly for many resources. This may be catastrophic in a larger scale but looking at singular bushfires, close-by residents along with firefighters and local fauna are all affected by these bushfires. The firefighters must be quick to stop the bushfire and arrive at the scene to prevent the fire from continuing, the local houses are at risk of falling trees or fire somehow catching close to them and local fauna lose their habitat and their lives in some cases.

Photosynthesis - Reference

Ishanns14 — 2018-11-26 04:20:21 UTC

Ducksters.com. (2018). Biology for Kids: Photosynthesis. [online] Available at: https://www.ducksters.com/science/photosynthesis.php [Accessed 26 Nov. 2018].

Home Science Tools. (2018). Photosynthesis: The Greenest Energy Projects + Lesson. [online] Available at: https://learning-center.homesciencetools.com/article/photosynthesis-science/ [Accessed 26 Nov. 2018].

Science, L. and Earth, P. (2018). What Is Photosynthesis?. [online] Live Science. Available at: https://www.livescience.com/51720-photosynthesis.html [Accessed 26 Nov. 2018].

Smithsonian Science Education Center. (2018). What is Photosynthesis. [online] Available at: https://ssec.si.edu/stemvisions-blog/what-photosynthesis [Accessed 26 Nov. 2018].

Bush fire

karnik_wadhawan — 2018-11-26 04:21:11 UTC

Example of Combustion in everyday life.

Grass Fire

karnik_wadhawan — 2018-11-26 04:25:00 UTC

Example of Combustion in everyday life.

Combustion Bibliography

karnik_wadhawan — 2018-11-26 04:26:04 UTC

Resources Used:

Australian Government n.d., Bushfire, ACT, accessed 23 November 2018, <http://www.ga.gov.au/scientific-topics/hazards/bushfire>.
Britannica 2018, Hydrocarbon, accessed 22 November 2018, <https://www.britannica.com/science/hydrocarbon>.
ThoughtCo. n.d., Combustion Reactions in Chemisty, accessed 22 November 2018, <https://www.thoughtco.com/combustion-reactions-604030>.

Corrosion - What is it?

jesvi_john — 2018-11-26 04:30:28 UTC

Corrosion is wearing of metal due to chemical reaction mainly by oxidation or by other chemicals. It occurs when a gas or liquids reacts with the surface of a metal object in the presence of some sort of moisture, eg; water. Corrosion products such as rust and patina stay on the surface on the metal, protecting metal beneath them from corrosion. Removing the corrosion products often re expose the metal to oxidation and continues the corrosion. All metals can corrode such as pure iron which is quicker to corrode than stainless steel, which mix iron with other alloys, is slower to corrode. Those that are not can be protected by coating or painting the surface.

Reactants and Products

jesvi_john — 2018-11-26 04:31:40 UTC

The common reactants of corrosion is iron, water/moisture and oxygen, which produces iron oxide or ‘rust’. Addition of salt can make the reaction faster.

Corrosion is a exothermic reaction, therefore releases heat into the atmosphere. They require activation energy to break bonds and releases more energy after the reaction.

Equation of Iron Oxide

jesvi_john — 2018-11-26 04:32:05 UTC

The worded equation of the chemical reaction is Iron (Fe) + Water (H2O) + Oxygen (O) = Iron oxide.

the chemical equation to this corrosion is 4(Fe) + 6 H2O+ 3 O2 ---> 4Fe(OH)3.

Corrosion in Nature

jesvi_john — 2018-11-26 04:32:46 UTC

In the world, anything made out of metal is susceptible to corrosion, Bridges, Vehicles and construction machines. Natural things like rocks with iron in it can also rust when exposed to water and oxygen.

Corrosion References

jesvi_john — 2018-11-26 04:33:12 UTC

Chemical formulas 2016, accessed 22 November 2018, <http://www.chemicalformula.org/chemistry-help/corrosion>.

What is Corrosion 2017, Britannica, accessed 22 November 2018, <https://www.britannica.com/science/corrosion>.

Terance, B 2017, Metal Corrosion, The balance, accessed 22 November 2018, <https://www.thebalance.com/what-is-corrosion-2339700>.

New York Times 2017, Corrosion, New york, accessed 26 November 2018, <https://www.nytimes.com/1987/04/14/science/science-watch-evidence-of-corrosion.html>.

Life's affected by Corrosion

jesvi_john — 2018-11-26 04:34:18 UTC

The World Corrosion Organization estimates the global cost of corrosion to be about US$ 2.2 trillion annually. 25% of these damages can be prevented by applying simple coating to the machine or structure made of metal. Corroded bridges, buildings, ships, and other metal structures can and do cause injury and death. Ship breaking workers, who dismantle old ships are particularly at risk as rusted parts of the ship can fall apart unexpectedly and cause injuries or death.

Acid-Base Reactions - Bibliography

josh_blenkiron — 2018-11-26 04:41:19 UTC

Akdeniz, A. (2018). How do you identify an acid-base reaction?. [online] Quora. Available at: https://www.quora.com/How-do-you-identify-an-acid-base-reaction [Accessed 26 Nov. 2018].

Aqion.de. (2018). pH of Common Acids and Bases. [online] Available at: http://www.aqion.de/site/191 [Accessed 26 Nov. 2018].

Fp.utm.my. (2018). Neutralisation in Our Daily Lives. [online] Available at: http://www.fp.utm.my/projek/psm/webtlr/Neutralisation/learning2b.html [Accessed 26 Nov. 2018].

Helmenstine, A. (2018). Formulas of Common Acids and Bases. [online] ThoughtCo. Available at: https://www.thoughtco.com/formulas-of-common-acids-and-bases-603663 [Accessed 26 Nov. 2018].

Hyperphysics.phy-astr.gsu.edu. (2018). Acid-Base Reactions. [online] Available at: http://hyperphysics.phy-astr.gsu.edu/hbase/Chemical/acidbase.html [Accessed 26 Nov. 2018].

Science Buddies. (2018). Acids, Bases, & the pH Scale. [online] Available at: https://www.sciencebuddies.org/science-fair-projects/references/acids-bases-the-ph-scale [Accessed 26 Nov. 2018].

Socratic.org. (2018). What are the products of Sodium hydroxide + hydrochloric acid? | Socratic. [online] Available at: https://socratic.org/questions/what-are-the-products-of-sodium-hydroxide-hydrochloric-acid [Accessed 26 Nov. 2018].

Terragis.bees.unsw.edu.au. (2018). terraGIS Soil. [online] Available at: http://www.terragis.bees.unsw.edu.au/terraGIS_soil/sp_soil_reaction_ph.html [Accessed 26 Nov. 2018].

The Student Room. (2018). Exothermic Reactions. [online] Available at: https://www.thestudentroom.co.uk/showthread.php?t=2224264 [Accessed 26 Nov. 2018].

Diagram

jesvi_john — 2018-11-26 23:00:53 UTC

jesvi_john — 2018-11-26 23:04:25 UTC

Rock corrosion

jesvi_john — 2018-11-26 23:05:28 UTC

Bridge corrosion

Evidence of corrosion

jesvi_john — 2018-11-26 23:08:30 UTC

When the corrosion reaction take place metal corroding will have a loss of lustre, there will be a new outer layer formed, mostly brown in colour

jesvi_john — 2018-11-26 23:11:09 UTC

Iron chain losing lustre and a new layer of iron oxide formed

jesvi_john — 2018-11-26 23:13:38 UTC

How photosynthesis occurs

Ishanns14 — 2018-11-26 23:13:54 UTC

jesvi_john — 2018-11-26 23:19:37 UTC