We are given the molar concentration of an aqueous solution of weak acid and the pH ofthe solution, and we are asked to determine the value of Ka for the acid.
The first step in solving any equilibrium problem is to write the equation for the equilibriumreaction. The ionization of benzoic acid can be written as seen in the attached image (1).
The equilibrium-constant expression is the equation number (2)
From the measured pH, we can calculate pH as seen in equation (3)
To determine the concentrations of the species involved in the equilibrium, we imagine that thesolution is initially 0.10 M in HCOOH molecules. We then consider the ionization of the acidinto H+ and HCOO-. For each HCOOH molecule that ionizes, one H+ ion and one HCOO- ionare produced in solution. Because the pH measurement indicates that [H+] = 1x 10^-4 M atequilibrium, we can construct the following table as seen in the equation number (4)
To find the value of Ka, please see equation (5):
We can now insert the equilibrium concentrations into the expression for Ka as seen in equation (6)
Therefore, 2.58x10^-4 M is the concentration of benzoic acid to have a pH of 4.0
Answer:
a generator that allows them to convert kinetic energy into potential energy
Explanation:
Rescue workers can accomplish this by using a generator that allows them to convert kinetic energy into potential energy. Such as a crank generator, with these, they spin a crank with their hands and the generator takes that kinetic energy that is building up through the work that the rescuer is exerting and converts it to potential electric energy that can properly be used to provide energy to the batteries for their equipment. This is what is generally used for situations such as what rescuers go through when there is no electricity around.
1 g/cm³ --------------- 0.1 kg/dL
7.86 g/cm³ ---------- ?
7.86 x 0.1 / 1 => 0.786 kg/dL
D = m / V
0.786 = 3.56 / V
V = 3.56 / 0.786
V = 4.529 dL
<span>hope this helps!</span>
I would measure by its height and width
Answer:
The first step in the Scientific Method is to make objective observations. These observations are based on specific events that have already happened and can be verified by others as true or false. Step 2. Form a hypothesis.