chem hw 21

The pH indicates if a solution is acidic, neutral, or basic, by the concentration of hydronium ions.

As the hydronium concentration increases, the solution is more acidic, and the pH decreases.

Carbonic acid, H2CO3

Sulfur dioxide in the atmosphere mixed with rain water produce sulfuric acid, which is acid rain.

The pollutant sulfur dioxide is produced from the combustion of oil and coal.

The corrosive properties are no longer present because the acid and base no longer exist. Instead they have chemically reacted with each other to form completely new substances - salt and water - that are not so corrosive.

The concentration of hydronium ions is typically so small it needs to be stated using scientific notation. The pH scale, therefore, is one of convenience.

As water is added to an acidic solution, the hydronium ions becoem more dilute, that is, less concentrated. thus the pH increases.

Yes, provided that the added acidic solution is less concentrated with hydronium ions. For example, a 1 M solution of HCl will become less acidic if you were to add to it a .01 M solution of HCl. The .01 M solution has the effect of diluting the 1 M solution.

Beach sand from the Caribbean and many other tropical cliamtes is made primarily of the calcium carbonate remains of coral and shelled creatures. Vinegar is an acid and the calcium carbonate is a base. The reaction between the two results in the formation of carbon dioxide, which creates bubbles as it is formed. California beach sand primarily comes from the erosion of rocks and minerals, which are mostly made of inert silicon dioxide, SiO2.

As the soda water loses carbon dioxide molecules if is losing the carbonic acid that these carbon dioxide molecules form when in solution. Thus, the pH of a flat soda is typically higher than the pH of the same soda when carbonated.

Add it some vinegar. If the toothpaste starts to bubble, there is a good chance it contains calcium carbonate.

It is the alkaline character of limestone (also known as calcium carbonate) that serves to neutralize waters that might be acidified in the mid wester United States.

The product of the hydroxide ion and hydronium ion concentration is always equal to 1 x 10 ^-14. So if the hydroxide ion concentration equals 1 x 10 ^-14 M, then the hydronium concentration must be equal to 1 x 10 ^-10 M, because these two values multiply together to equal 1 x 10^14.

• pH = -log (10 ^-10) = -(-10) = 10
• This solution is basic.

pH = -log (10^4) = - (-4) = 4 This solution is acidic.

Zinc coats the nail, and oxidizes to form a thin layer of zinc oxide, and inert, insoluble substance that protects the iron underneath.

Electrolysis is the use of electrical energy to produce chemical change. Recharging a car battery is an example of electrolysis. It is the opposite of the oxidation-reduction reaction that goes on inside a battery. It is using electrical energy to reverse the oxidation-reduction reaction.

Chemicals are reduced at the cathode (negative end of the battery).

The salt bridge completes the electrical circuit, by allowing ions to migrate such that neither container builds up any positive or negative charge.

Electrochemistry is the study or the relationship between electrical energy and chemical change.

The elements in the lower left hand corner.

An oxidizing agent is actually reduced in the reaction, but it causes the oxidation of the reducing agent in the reaction.

The elements in the upper right hand corner.

The iodine atoms, I, gain electrons and are reduced, while the bromine ions, Br, lose electrons and are oxidized.

The tin ion, Sn++, is the oxidizing agent because it causes the silver, Ag, to lose electrons. Meanwhile, the silver atoms, Ag, are the reducing agents because they cause the tin ion to gain electrons.

The sulfur is oxidized as it gains oxygen atoms for sulfur dioxide.

An oxidizing agent causes other materials to lose electrons. It does so by its tendency to gain electrons. Atoms with great electronegativity tend to have a strong attraction for electrons and, therefore, also behave as strong oxidizing agents. Conversely, a reducing agent causes other materials to gain electrons. It does so by its tendency to lose electrons. Atoms with great electronegativity, therefore, have little tendency to behave as reducing agents.

The electrons flow from the submerged nail to the copper ions in solution.

As the carbon of propane, C3H8, forms carbon dioxide, CO2, it is losing hydrogen and gaining oxygen, which tells us that the carbon is being oxidized, which is opposite of what happens to a carbon during photosynthesis.

Recognize that there is a total charge of +2 with the reactants, but a total charge of +1 with the products, which is not balanced. To balance the charges, we need two silver ions, Ag +. But to account for TWO silver ions, we also need two silver atoms, Ag.

Combustion reactions are generally exothermic because they involve the transfer of electrons to oxygen, which of all atoms in the periodic table has one of the greatest tendencies for gaining electrons.

One of the products of combustion is water vapor.