Which is a single ringed nitrogeo base? A)adenine B)guanine C)thymine D)ribose

A certain first-order reaction has a rate constant of 2.15×10−2 s−1 at 20 ∘C. What is the value of k at 55 ∘C if Ea = 72.0 kJ/mo

adell [148]

Answer:

$k_2=0.504s^{-1}$

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to calculate the rate constant at 55 °C by using the temperature-variable version of the Arrhenius equation:

$ln(\frac{k_2}{k_1} )=-\frac{Ea}{R}(\frac{1}{T_2} -\frac{1}{T_1} )$

Thus, we plug in the temperatures, activation energy and universal constant of gases in consistent units to obtain:

$ln(\frac{k_2}{0.0215s^{-1}} )=-\frac{72000\frac{J}{mol}}{8.3145\frac{J}{mol*K}}(\frac{1}{55+273} -\frac{1}{20+273} ) \\\\ln(\frac{k_2}{0.0215s^{-1}} )=3.154\\\\k_2=0.0215s^{-1}exp(3.154)\\\\k_2=0.504s^{-1}$

Regards!

3 0

2 years ago

To indicate the pH of a substance, one can use a dye that is both an acid and that appears as different colors in its protonated

PIT_PIT [208]

Answer:

The pH of the solution is 7.8

Explanation:

The concentration of the solution is 0.001M and the dye could be in its protonated and deprotonated forms. If the concentration of the protonated form [HA] is 0.0002 M the concentration of the deprotonated form will be the subtraction between the concentration of the bye and the concentration of the protonated form:

[A-] = 0.001M - 0.0002M = 0.0008M

Also, the Henderson-Hasselbalch equation is

$pH = pKa + Log \frac{[A^{-}]}{[HA]}$

this equation shows the dependency between the pH of the solution, the pKa and the concentration of the protonated and deprotonated forms. Thus, replacing in the equation

$pH = 7.2 + Log \frac{0.0008M}{0.0002M} = 7.8$

3 0

2 years ago

Calculate the pH and pOH of 0.010 mol OH- per liter

Sati [7]

We can use a variety of formulas to determine our answers here.

Our formula for pOH is -log(mol), and we can plug it in as -log(0.010). Take note that OH- is a base, not an acid.

So, the pOH of OH- is 2.

To find pH we can set up this simple equation:
pH + pOH = 14
All we need to do is subtract 2 from 14, therefore the pH is 12.

This makes sense since acids range in the pH of 1-6, and we are dealing with a base. Hope I could help!

7 0

2 years ago

Number of electrons the atom my accept from another atom?

ZanzabumX [31]

Answer:

Yes atoms can accept the electrons from another atom like

Chlorine accept electron from hydrogen.

Explanation:

8 0

2 years ago

How did max planck contribute to the modern atomic theory?

Igoryamba

Answer:

Planck made many contributions to theoretical physics, but his fame rests primarily on his role as originator of the quantum theory. This theory revolutionized our understanding of atomic and subatomic processes, just as Albert Einstein's theory of relativity revolutionized our understanding of space and time

5 0

2 years ago

Read 2 more answers