Which is the best description of hydrogen bonding? Which is the best description of hydrogen bonding? the association between a hydrogen atom which is somewhat positive because it is bonded to a small electronegative atom and an atom of O, N or F on another molecule the association between hydrogen of one molecule and a region of another molecule which has become negative due to temporary shifts in electron density the unique chemical bonds between hydrogen and any other atom in the same molecule the temporary attraction between hydrogen atoms on different molecules resulting from shifts in electron density the polarity associated with a bond between hydrogen and a small electronegative atom to which it is bonded

Answer:

The nervous system

Explanation:

The nervous system send messages from the brain to the muscles to move.

The nervous system, particularly the somatic nervous system, provides the impulses that enable the muscular system to function, allowing for a wide range of both voluntary and involuntary movements.

The muscles of the body, part of the muscular system, would not function without the nervous system providing the impulses that cause the muscles to act. This is particularly true for the skeletal muscles, which completely depend on signaling from the nervous system to work properly.

Our nervous system is divided into the somatic nervous system (SNS) and the autonomic nervous system, with the SNS responsible for the contraction of our skeletal muscles. This mechanism enables a wide range of voluntary and involuntary movements, like standing, walking, running, grasping items, and reflex actions; some of which happen automatically due to habit learning or procedural memory.

Responses can be voluntary, such as the contraction of skeletal muscles, or involuntary like the contraction of smooth muscles, regulation of cardiac muscles, and activation of glands.

https://brainly.com/question/24255030

#SPJ3

In the periodic table, atomic radius decreases as we move left to right across a period. In period 3, this results in the elements Si, Mg, Na, and Al being ranked in decreasing atomic radius as follows: Na, Mg, Al, and Si.

The atomic radius of an element is generally defined as the total distance from the center of an atom's nucleus to its outermost shell of electrons. In the periodic table, the atomic radius tends to decrease as we move across a period from left to right, and it increases as we move down a group.

Considering the elements Si, Mg, Na, and Al, all these elements are located in the same period in the periodic table, period 3. Therefore, as we move across this period from left to right, the atomic radius should decrease.

And following this rule, the elements should rank in this order from largest to smallest atomic radius: Na > Mg > Al > Si.

https://brainly.com/question/32036952

#SPJ12

The elements Si, Mg, Na, Al in order from largest to smallest atomic radius would be Na, Mg, Al, Si. This is based on the general trend in the periodic table where atomic radius decreases as you move from left to right across a period and increases as you move down a group.

In the periodic table, atomic radius generally decreases as you move from left to right across a period and increases as you move down a group. So, considering this, Si, Mg, Na, Al are positioned in the periodic table as follows: Na (period 3, group 1), Mg (period 3, group 2), Al (period 3, group 13), and Si (period 3, group 14). Following the trend in the periodic table, the order from largest to smallest atomic radius would be Na, Mg, Al, Si.

https://brainly.com/question/13607061

#SPJ2

The answer is a. Melting

Answer:

Answer:  

An article discussing mineral resources written by the United States Geological Survey.

A study describing clinical trials of a new medication in the Journal of Medicinal Chemistry.

Explanation:

A reliable source can be define as the source of information which can be used for the purpose of research. The reliable source should be thorough, well reasoned and must be supported by the evidences. It can be based on experimental trials and outcomes of the previous research. It can be proved by the authentic organization and institution.

The following are the examples of reliable sources:

An article discussing mineral resources written by the United States Geological Survey.: This is the authentic reliable source as the information is provided by recognized survey organization.

A study describing clinical trials of a new medication in the Journal of Medicinal Chemistry.: This is reliable source because the information is provided on the basis of the clinical trials the results of which will be reliable as in journals only the reliable information is presented.

Answer:

Explanation:

Nucleons are the particles that are in the nucleus of the atom, i.e. protons and neutrons.

So, the nucleon number is the number of protons and neutrons.

Other name for nucleon number is mass number, and it is represented by the letter A:

nucleon number = mass number = A = protons + neutrons.

Carbon-14 is the particular name, indicating the mass number, of the isotope of carbon with mass number 14.

So, the nucleon number of carbon-14 is indicated in its name, and it is 14.

The name carbon-14 identifies completely the isotope because, the atomic number of carbon is the same for every atom (isotope) of carbon:

Answer:

- 0.028 °C

Explanation:

Where, ΔTf is the depression in water freezing point (ΔTf = ???°C).

Kf is the molal freezing point depression constant of the solvent (Kf = 1.86 °C/m).

m is the molality of AlCl₃ (m = 0.015 m).

∴ ΔTf = Kf.m = (1.86 °C/m)(0.015 m) = 0.0279 °C ≅ 0.028 °C.

∵ ΔTf = freezing point of pure water - freezing point of the solution in presence of AlCl₃.

∴  freezing point of the solution in presence of AlCl₃ = freezing point of pure water - ΔTf = 0.0 °C - 0.028 °C = - 0.028 °C.

Answer:

[tex]\boxed{\text{(D) 2 HCHO}_{2}}[/tex]

Explanation:

HCOOH + H₂O ⇌ H₃O⁺ + HCOO⁻

HCHO₂ is a weak acid. It dissociates only to a few percent, so there will be more HCHO₂ than H₃O⁺ present.

After H₂O, the most abundant species will be undissociated HCHO₂, so the answer will be either (B) or (D).

We can use an ICE table to organize the calculation of the pH.

                  HCOOH +H₂O ⇌ H₃O⁺ + HCOO⁻

I/mol·L⁻¹:        0.5                       0            0

C/mol·L⁻¹:       -x                        +x           +x

E/mol·L⁻¹:     0.5 - x                    x             x

[tex]K_{\text{a}} = \dfrac{\text{[H}_{3}\text{O}^{+}]\text{HCOO}^{-}]} {\text{[HCOOH]}} = 2 \times 10^{-4}\\\\\dfrac{x^{2}}{0.5-x} = 2 \times 10^{-4}[/tex]

Check for negligibility of x

[tex]\dfrac{ 0.5 }{2 \times 10^{-4}} = 2500 > 400.[/tex]

∴ x ≪ 0.5

[tex]\dfrac{x^{2}}{0.5} = 2 \times 10^{-4}[/tex]

x² = 0.5 × 2 × 10⁴ = 1 × 10⁻⁴

x = √(1 × 10⁻⁴) = 1 × 10⁻²

[H₃O⁺] = x mol·L⁻¹ = 1 × 10⁻² mol·L⁻¹

pH = -log[H₃O⁺] = -log(1 × 10⁻²) = 2

The correct answer is [tex]\boxed{\textbf{(D) 2 HCHO}_{2}}[/tex].

Answer:

Q35 (C); Q36 (B)

Explanation:

Li₃N + 2H₂ ⇌ 2LiNH₂ + 2LiH; ΔH° = -192 kJ·mol⁻¹

Q35. Reaction rate

The reaction is slow below because it has a high activation energy.

ΔH, ΔS, and ΔG determine the position of equilibrium and the spontaneity of the reaction, not its rate.

Q36. Maximizing amount of H₂

The reaction is exothermic. According to Le Châtelier's Principle, increasing the temperature will shift the position of equilibrium to the left and increase the amount of hydrogen.

Increasing the pressure will shift the position of equilibrium to the side with fewer moles of hydrogen.

Decreasing the pressure will shift the position of equilibrium to the side with more moles of hydrogen.

The correct answer is (B) increasing the temperature and decreasing the pressure .

Answer:The answer is D

Explanation:

The inner transition elements are those in the two long rows at the bottom of the Periodic Table.

The lanthanide series starts after Ba in Period 6, and the actinide series starts after Ra in Period 7.

Thus, we would predict their electron configurations to be of the form

However, the energy levels of the ns, (n-1)d, and (n-2)f orbitals are so close in energy that there are many exceptions to our predictions

For example, here are some electron configurations.

La = [Xe]6s²5d (not [Xe]6s²4f)

Ce = [Xe]6s²4f5d (not [Xe]6s²4f²)

Pr = [Xe]6s²4f³ (as predicted)

Thus, their valence electrons can be in both s and f (and sometimes d) sublevels.

Read more on Brainly.com - https://brainly.com/question/11535806#readmore

The answer should be d

Answer is hope this helps

Answer:

Cf

Explanation:

californium

just be postice and you will find the answer