An atom of aluminum has 13 protons and 14 neutrons. what is the atomic mass

Which of the following acids is the WEAKEST? The acid is followed by its Ka value.HF, 3.5 × 10^-4HNO2, 4.6 × 10^-4HCN, 4.9 × 10^

Mila [183]

Answer:

HCN

Explanation:

There are several factors that can tell us when an acid is stronger than another, which are the following:

1. The Polarity of the X - H Bond

2. Size of the X atom.

3. Charge on the acid.

4. Oxidation state of the central atom

5. Values of Ka and pKa.

From all of this factors, we can see that the exercise is already giving us values of Ka, and also we have different types of acid, not only with the form H - X

So, we will base the force of an acid by it's pKa value.

The pKa value which is calculated with the expression:

pKa = -logKa

pKa is a value that indicates how strong is the acid you are working with. This value can vary depending on factors such the charge of the acid. I f this charge can be easily distributed in resonance structures, the compound is more acidic, and therefore the pKa value is lower.

The lower the pKa, the more acidic the compound is.

So calculating the pKa on every structure we have:

HF: pKa = -log(3.5x10^-4) = 3.46

HNO2: pKa = -log(4.6x10^-4) = 3.34

HCN: pKa = -log(4.9x10^-10) = 9.31

HCOOH: pKa = -log(1.8x10^-4) = 3.74

HClO2: -log(1.1x10^-2) = 1.96

So according to all this values, we can conclude that the weakest acid is the HCN

4 0

3 years ago

Indicate what happens to the concentration of Pb2+ in each half cell

Taya2010 [7]

Answer:

Your questions requires diagrams of the cell to get which one is on the left or right. However, see the attached file below

The correct answer is (d) the left half-cell will decrease in concentration; and the right half-cell will increase in concentration.

Explanation:

The concentration of the Pb2+ increases in the oxidation half cell while the concentration of the Pb2+ decreases in the reduction half cell during the reaction.

In the Left Beaker (Left half cell), their is less concentration

Pb(s) ---> Pb2+(aq) + 2 e- Concentration of Pb2+(aq) increase ; Electrons going out from this side

In the Right Beaker (right half cell), their is more concentration

Pb2+(aq) + 2 e- ---> Pb(s) Concentration of Pb2+(aq) decrease ; Electrons coming in to this side

Electrons will flow from Left to Right direction.

3 0

3 years ago

Explain using the particle theory why objects generally expand when heated and contract when cooled?

seraphim [82]

When heated, particles vibrate faster, thus increasing the distance between one another. The distance between these particles results in changes of state. Therefore, increased molecular motion results in expansion of an object. This works vice versa for cooling. As the vibrations slow down, the particles become closer together. This results in contraction.

4 0

3 years ago

Name three ways in which unicellular organisms can move. Describe one of them.

Viefleur [7K]

Answer:

Unicellular organisms achieve locomotion using cilia and flagella. By creating currents in the surrounding environment, cilia and flagella can move the cell in one direction or another.

Explanation:

3 0

2 years ago

Read 2 more answers

21. What is happening in terms of energy and attractive/repulsive forces when atoms come together and

muminat

Answer:

So A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms. These electrons are simultaneously attracted by the two atomic nuclei. A covalent bond forms when the difference between the electronegativities of two atoms is too small for an electron transfer to occur to form ions.

Explanation:

words to know: covalent bond, electronegativities, and simultaneously

Covalent Bond: A chemical bond formed when electrons are shared between two atoms. Usually each atom contributes one electron to form a pair of electrons that are shared by both atoms.

Electronegativities: the degree to which an element tends to gain electrons and form negative ions in chemical reactions.

Simultaneously: at the same time.

hope this helps!

6 0

2 years ago