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3 years ago

What is the ph of pure water at 40.0°c if the kw at this temperature is 2.92 × 10-14?

Chemistry

1 answer:

olganol [36]3 years ago

5 0

Answer: pH = 6.77

Explanation:

1) Chemical equilibrium

2 H₂O (l) ⇄ H₃O⁺ (aq) + OH⁻ (aq)

2) Equilibrium constant, Kw

Kw = [H₃O⁺] × [OH⁻]

By stoichiometry [H₃O⁺] = [OH⁻]. Call it x

Kw = x²

x² = 2.92 × 10⁻¹⁴ M²

x = √ (2.92 × 10⁻¹⁴) = 1.709 × 10⁻⁷ M = [H₃O⁺]

3) pH

pH = - log [H₃O⁺] = - log (1.709 × 10⁻⁷) = 6.77

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Preteins vary widely in structure, whereas nucleic acids have rather uniform structures. How do you account for this major diffe

Vedmedyk [2.9K]

Answer:

As proteins vary widely in structures than that of nucleic acid there will be greater structural and functional diversity of proteins than nucleic acid.

Explanation:

Proteins are the macromolecules which have more structural diversity than any other macromolecules such as carbohydrate,lipid,nucleic acid.

The are 4 types of protein structure primary structure,secondary structure,tertiary structure and Quaternary structure.Due the existence of many types of structure various protein exhibit various functions.

On the other hand nucleic acid such as DNA has widely accepted secondary structure discovered by watson and crick.As a result there is no such structural diversity exist in nucleic acid.

4 0

3 years ago

Chemistry

notsponge [240]

Answer: Ca

Explanation:

5 0

3 years ago

A student has a 2.19 L bottle that contains a mixture of O 2 , N 2 , and CO 2 with a total pressure of 5.57 bar at 298 K . She k

Sergeeva-Olga [200]

Answer: The partial pressure of oxygen gas is 2.76 bar

Explanation:

To calculate the number of moles, we use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 5.57 bar

V = Volume of the gas = 2.19 L

T = Temperature of the gas = 298 K

R = Gas constant = $0.0831\text{ L bar }mol^{-1}K^{-1}$

n = Total number of moles = ?

Putting values in above equation, we get:

$5.57bar\times 2.19L=n\times 0.0831\text{ L. bar }mol^{-1}K^{-1}\times 298K\\\\n=\frac{5.57\times 2.19}{0.0831\times 298}=0.493mol$

To calculate the mole fraction of carbon dioxide, we use the equation given by Raoult's law, which is:

$p_{A}=p_T\times \chi_{A}$ ........(1)

where,

$p_A$ = partial pressure of carbon dioxide = 0.318 bar

$p_T$ = total pressure = 5.57 bar

$\chi_A$ = mole fraction of carbon dioxide = ?

Putting values in above equation, we get:

$0.318bar=5.57bar\times \chi_{CO_2}\\\\\chi_{CO_2}=\frac{0.381}{5.57}=0.0571$

Mole fraction of a substance is given by:

$\chi_A=\frac{n_A}{n_A+n_B}$

We are given:

Moles of nitrogen gas = 0.221 moles

Mole fraction of nitrogen gas, $\chi_{N_2}=\frac{0.221}{0.493}=0.448$

Calculating the partial pressure of oxygen gas by using equation 1, we get:

Mole fraction of oxygen gas = (1 - 0.0571 - 0.448) = 0.4949

Total pressure of the system = 5.57 bar

Putting values in equation 1, we get:

$p_{O_2}=5.57bar\times 0.4949\\\\p_{O_2}=2.76bar$

Hence, the partial pressure of oxygen gas is 2.76 bar

6 0

3 years ago

What are the main method of combination?

Pepsi [2]

Explanation:

Each atom type contains the same number of protons. Chemical bonds link elements together to form more complex molecules called compounds. A compound consists of two or more types of elements held together by covalent or ionic bonds

7 0

2 years ago

What causes attraction and repulsion between atoms?

Jobisdone [24]

Answer:

Repulsive forces exist only when atoms are very close to each other. (3/14) "They [the atoms] will approach until both nuclei will simply shove each other because both of them are positive." The balance between the attraction and repulsion forces determines how close the atoms can get. The relationships between the magnitude and direction of repulsive and attractive forces. A stable state of a bond is when attractive forces balance repulsion forces. “A stable state between two atoms is when they attract each other with a force that equals the force that they repel each other.”

7 0

3 years ago