The pH at half the equivalence point is equal to the pKa of the acid.

In this case, two variables are changed between the initial and final containers: volume and temperature. Since we are looking for the final pressure on the container, we can use the combined gas law in order to solve for the final pressure:

When using the ideal gas law, remember that temperature must be in Kelvin, not Celsius, so we will need to convert.

Use the given values to solve for the final pressure.

The most common Lewis bases are anions, and therefore, have unpaired valence electrons which may be donated to Lewis acids. The concept of donating and/or accepting hydrogens refers to the Bronsted-Lowry definition of acids. A Bronsted-Lowry acid donates hydrogens.

Use Dalton's law of partial pressure:

Where is the partial pressure of oxygen and is the mole fraction of oxygen. Plug in known values and solve.

In this case, two variables are changed between the initial and final containers: volume and temperature. Since we are looking for the final pressure on the container, we can use the combined gas law in order to solve for the final pressure:

When using the ideal gas law, remember that temperature must be in Kelvin, not Celsius, so we will need to convert.

Use the given values to solve for the final pressure.

Ions of atoms vary in their size. When an atom gains electrons the atomic size increases, and when an atom loses electrons the atomic size decreases. Nitrogen with a formal charge of negative three will have the largest size because it has the most electrons. Remember that adding electrons will cause a negative ion, while removing electrons will cause a positive ion.

We should first remember the difference between sulfate, sulfite, and sulfide. Sulfate is , sulfite is ` and sulfide is .

The only answer choices that could be right must have in them. We then need to see that barium usually has a charge of , as the periodic table shows us, and so we need a charge of to cancel that out. The answer is .

The most common Lewis bases are anions, and therefore, have unpaired valence electrons which may be donated to Lewis acids. The concept of donating and/or accepting hydrogens refers to the Bronsted-Lowry definition of acids. A Bronsted-Lowry acid donates hydrogens.

Use the the dissociation constant for water to calculate the concentration of hydrogen ions and then convert to the pH scale.

Rearrange the dissociation constant to solve for the hydrogen ion concentration:

Plug in the given concentrations to find the actual hydrogen ion concentration:

Convert the hydrogen ion concentration to pH scale:

Boyle's Law is:

The initial volume () and pressure () of the gas is given. The volume changes to a new volume (). Our goal is to find the new pressure (). Solving for the new pressure gives:

Notice the answer has 3 significant figures.