What Difference Does it Make? Trivia Quiz

Answer: By reaction with water in the atmosphere

These gases dissolve in water vapor in the atmosphere and from there can form strong acids such as nitric acid or sulfuric acid in a number of steps. Contrary to popular belief, the purest rainwater is not neutral, it's acidic too! This is because it absorbs carbon dioxide gas from the atmosphere, forming carbonic acid in solution.

However carbonic acid is MUCH weaker than sulfuric and nitric acid and doesn't have the adverse impacts of acid rain on either man-made structures or the environment.

Answer: Hydrogen and Oxygen

Production of hydrogen and oxygen in this manner requires a large amount of energy and hence is not performed on large scale. However, the use of renewable energy sources including solar and wind power to provide the energy required is continuing to make water electrolysis more attractive, which may be important in the future when cars fueled by hydrogen become more common. One unusual application of water electrolysis is that it provides the oxygen needed for the astronauts in spacecraft.
The equation for this process is:
2 H2O (liquid) -> 2 H2(gas) + O2 (gas)
You may notice that the number of hydrogen atoms on each side of the equation is equal (four) as is the number of oxygen atoms (two). This meets the requirement for Conservation of Mass in a chemical reaction - mass cannot be created nor destroyed in a (non-nuclear) chemical reaction.

Answer: Rapidly expanding gas from the combustion

The combustion of gasoline (petrol) creates a number of products including water vapor (gas) and carbon dioxide plus many other gases in smaller amounts. The important feature is that when a liquid is turned into a gas, a very large expansion takes place as gas is far less dense than the liquid.

These gases are rapidly created in the confined chamber of the cylinder therefore creating great pressure that is then used to push down the piston, therefore creating the mechanical energy to drive the motor and the car.

Answer: Reduction and Oxidation

Batteries, and electrochemical reactions in general, involve the movement of electrons from one chemical substance to another. In a battery there are two electrodes - an anode and a cathode - made of different materials (often metals). These electrode materials differ in their 'desire' to gain or lose electrons based on their intrinsic electronic properties.

The electrodes are separated using an electrolyte gel or paste. Electrons can travel through an external circuit from the electrode wanting to lose electrons (anode) to the electrode wanting to gain electrons (cathode), providing by a current.

The voltage of the battery can be altered by changing the materials making up the electrodes.

Answer: Iron and Oxygen

The process where a metal reacts with oxygen in the air is an electrochemical reaction called oxidation. Rusting involves the iron (Fe) metal being oxidized to ferric ions (Fe3+) by the oxygen, and concurrently, the oxygen is reduced by the iron to water with the involvement of some H+ ions (hence the need for water for the reaction to occur as this is the source of the H+). Rust is an amorphous substance and can be worn away much quicker than the metal therefore weakening the material. Rusting cannot be reversed but can be minimized. Salt water enhances the rusting reaction as it provides an efficient electrolyte - salt water conducts charge (and electricity) much more readily than fresh water because of the much high concentration of ions such as sodium (Na+) and chloride (Cl-). Hence cars near the seaside (exposed to saltwater spray in the air or slightly salty rainfall) rust much faster than cars further inland. Salting of roads in wintertime in some locations also greatly increases the rate of rusting.

Metals like aluminum react with air and form a surface coating of unreactive aluminum oxide (Al2O3). This layer protects the underlying metal from further weakening.

Answer: Neutralization

While the lining of the stomach can normally easily handle the very acidic conditions (approx 0.5% hydrochloric acid) needed to help digest food, such a lining is not present in the esophagus. Hence when the acid moves upwards it causes chemical burns to the cells and extreme discomfort. Antacids comprise a wide range of relatively simple bases, usually a metal hydroxide such as aluminum hydroxide (Al(OH)3)), a metal bicarbonate such as sodium bicarbonate (NaHCO3 - baking soda) or a metal carbonate such as calcium carbonate (CaCO3 - crushed limestone!).

Other formulations exist too. The essential role of these substances is that the anion (the bicarbonate, hydroxide or carbonate) will react with the H+ from the hydrochloric acid and form water.

Hence the acid (i.e. the H+) is neutralized.

Answer: Ammonia

The Haber-Bosch process was developed by the German chemist Fritz Haber and modified to work on an industrial scale by another German chemist and engineer, Carl Bosch. Both men received the Nobel Prize for this work - Haber in 1918 and Bosch in 1931. The process converts nitrogen and hydrogen gases into ammonia according to the equation:

N2 + 3H2 -> 2 NH3

The challenge of this reaction is that nitrogen gas - which makes up 78% of the atmosphere - is extremely unreactive. The process needs a catalyst, high pressure (around 150-250 atmospheres) and high temperatures (300-550 C). These conditions mean that ammonia production requires very large amounts of energy.

At the end of 2011, this reaction is still by far the most important process for making ammonia. Research continues to seek commercially viable alternatives including examining how certain simple bacteria (diazotrophs) can perform the same task at room temperature and atmospheric pressure!

The ammonia, usually added to the soil in form of a salt, provides a source of nitrogen, an essential nutrient, to growing plants.

Answer: The gas bubbles cause the batter to rise

The baking soda performs a similar function to yeast. Both are 'leavening agents' which cause the batter or dough to rise. This provides the wonderful fluffy and light texture to the final cake (or other baked goods). It is the neutralization reaction between the acidic components of the batter (which may include buttermilk, lemon juice, yogurt, vinegar, phosphates and cream of tartar) with the bicarbonate anion HCO3(-) that produces this carbon dioxide.

The gas bubbles form and are then trapped within the product as it cooks, causing the batter to expand, leaving the 'holes' in the finished cake.

This expansion will occur in any direction it can, hence the reason that cakes are usually cooked in a high-sided pan - otherwise they would expand sideways too and the final results would be a yummy, flatter and much wider cake! However, because bases such as sodium bicarbonate result in a bitter taste, too much baking soda will completely spoil the taste of the cake.

Answer: Speed up the rate of a chemical reaction

A catalyst speeds up the rate of a chemical reaction by providing a much lower activation energy barrier. The catalyst remains unchanged at the end of this reaction. Decreasing the time for a reaction to occur is often highly desirable as it saves both time and energy (and hence money) in the manufacturing process. One way to think about this is that the two chemicals to be reacted together are on one side of a hill (the 'activation energy' barrier).

The higher the hill, the longer it will take to climb and hence the slower the reaction. Reaction is complete when they reach the valley on the other side of the hill.

A catalyst provides another pathway to the valley on the other side which only involves climbing a small way up the hill hence the reaction is much faster. An alternative method of causing this reaction to go faster is to provide more energy to the reactants (e.g. by heating them) so that they get up and over that hill more quickly.

Answer: Oxygen

Trees are often called 'the lungs of the world' for their ability to turn carbon dioxide into oxygen, which we can then breathe. While this is true, many other plants (e.g. grasses, mosses, shrubs, flowers, algae) also photosynthesize, so having such plants around, even with no trees, is much better for our environment than no plants at all.

The other critical aspect of photosynthesis is that it traps energy from the sun and creates new plant material (biomass). This material provides a vital food resource for the rest of the ecosystem including us!