Chemical Reactions - AP Chemistry

Since no precipitation is predicted by the solubility rules, there will be no reaction.

Only the calcium and carbonate ions are reacting according to the solubility rules to form calcium carbonate.

Only Cd and S ions are interacting according to the solubility rules to form a solid precipitant.

Only the Ba and sulfate ions will react according to the solubility rules.

Only the Ag and Cl ions are reacting to form solid silver chloride.

Since no precipitation is predicted by the solubility rules, there will be no reaction.

Only the calcium and carbonate ions are reacting according to the solubility rules to form calcium carbonate.

Only Cd and S ions are interacting according to the solubility rules to form a solid precipitant.

Only the Ba and sulfate ions will react according to the solubility rules.

When writing/balancing a single replacement reaction, make sure to consult the activity series, because that will tell us if a reaction will actually take place. Remember to look at the cations (metals and hydrogen) and where they are in relation to each other on the activity series. The higher one on the activity series is the most reactive; so if the cation by itself is the most reactive, it will replace the other cation and a reaction will occur. Boyle's law explains the inverse relationship between volume and pressure with respect to certain amount of an ideal gas at constant temperature.

Potassium is a Group I element, so to get to a filled valence shell, it will lost one electron, yielding K^+.

Arsenic is a Group 5 element, so it needs to gain three electrons to obtain a filled valence shell, yielding $As^{-3}$.

In order to balance out the charges, the resultant salt will be K_3As.

First, we must know what ferrous sulfate is. Ferrous refers to , and sulfate has the formula . When we combine the two together we get .

Calcium is a divatent cation and iodide is a monovalent anion, so their salt is . The ion exchange reaction is then:

The net ionic equation is derived by removing all spectator ions from the total ionic equation (in which all ions are listed). To put it another way, the net ionic equation involves only the ions that participate in a reaction which, in this case, is the precipitation of barium sulfate.

Begin by writing all aqueous compounds in their dissociated (ionic) forms.

Cancel out any ions that appear in equal quantities on both sides of the equation. In this case, we can cancel the nitrate and potassium ions.

This is our net ionic equation.

When one molecule is converted into two or more smaller molecules, the reaction is considered a decomposition reaction. In this example, none of the elements under go a change in oxidation number, so this is not an oxidation-reduction reaction. (Calcium is always , oxygen is always , and carbon remains throughout the reaction.)

Combustion is the chemical reaction of a hydrocarbon with molecular oxygen, and it always produces carbon dioxide and water. Knowing the reactants and products, the unbalanced equation must be:

We start by balancing the hydrogens. Since there are 10 on the left and only 2 on the right, we put a coefficient of 5 on water.

Similarly, we balance carbons by putting a 4 on the carbon dioxide.

To find the number of oxygens on the right, we multiply the 4 coefficient by the 2 subscript on O (which gets us 8 oxygens) and then add the 5 oxygens from the 5 water molecules to get a total of 13. The needed coefficient for on the left would then have to be 13/2.

Because fractional coefficients are not allowed, we mutiply every coefficient by 2 to find our final reaction:

When we check the activity series, it is fairly easy to see that aluminum metal is more reactive than zinc metal. So, in this case, the two metals undergo a redox reaction, where the aqueous is reduced to solid , and the solid is oxidized to aqueous . These charges are the common oxidation states for zinc and aluminum and should be memorized.

Because is the new species, it bonds with 3 ions. The unbalanced equation is:

We note that there are 2 chlorine atoms on the left and 3 chlorine atoms on the right. To balance, we use a 3 coefficient on the left and a 2 coefficient on the right. This gives a total of 6 chlorine atoms on eahc side.

However, now we have also increased the amounts of zinc and aluminum. We copy the necessary coefficients to balance those—2 for aluminum on the left, 3 for zinc on the right—and we are done:

To find the net ionic form of this chemical equation, first balance the equation, then dissociate all soluble components. In other words, separate the aqueous terms into two separate molecules/atoms. For example, dissociates into and . After separating all soluble terms, balance the equation and cancel out any terms that repeat on both sides of the equation. For example, will be on both sides of the equation after separating all terms so you can cross them out. Below are the steps taken to find the net ionic form of this chemical equation.

Write out the dissociated forms of each species, if applicable.

Cross out species that appear on both sides of the equation. The net ionic equation is:

The typical double replacement reaction is as follows:

The anions are the chemical species being exchanged (both sulfur and chloride). Hence, the name double replacement is given to this particular reaction.

Combustion reactions always produce and excess heat. Depending on the molecule that is oxidized by oxygen, which in this case was methane , the ratios between and can vary.