PLEASE HELP

is this a chemical or physical change???

Answer:

92.4%

Explanation:

The volume per cubic meter of sodium preoccupy by the sodium ions is

[tex]V_{Na} = n \times V[/tex]

where;

volume (V) of each Na atom   = [tex]\dfrac{ 4}{3} \pi r^3[/tex]

Radius of each ion = 97.3 pm = 97.3 × 10⁻¹²

no.of atoms in the sample n =  mass of the sample / ( molar mass / NA)

mass of the sample per cubic metre =  911 kg/m³

∴

[tex]V = \bigg [ \dfrac{4}{3} \pi r^3 \bigg ] \bigg [\dfrac{MN_A}{m} \bigg ][/tex]

[tex]V = \bigg [ \dfrac{4}{3} \pi (97.3 \times 10^{-12} )^3 \bigg ] \bigg [\dfrac{ (911 kg/m^3 (m^3))(6.023\times 10^{23})}{27.7 \times10^{-3}\ kg/mol } \bigg ][/tex]

V = 0.07643 m³

The fraction of available conduction electrons are;

= (1 - V)

= 1 - 0.07643

= 0.92357

≅ 92.4%

napthalene: C10H8 sulphur: S02

Explanation:

C10H8

Explanation:

The reason why it is important to prepare for an disaster is because Being prepared can reduce fear, anxiety, and losses that accompany disasters. People also can reduce the impact of disasters (flood proofing, elevating a home or moving a home out of one's harm's way, and securing items that could shake loose in an earthquake) and sometimes avoid the danger completely.

The things you need to prepare for an disaster is

Answer:

Force F = 20N .

Mass m = 2.0 kg

Initial velocity u = 0

acceleration, a = 10m/s  

2

t = 1 sec.

Now Refer to the attachment, See the free body diagram of the block.

Force works on the block:-

Weight, W = mg

W = 2 × 10

W = 20N (which is Downward)  

Normal force N = mg cos37

N = 20 × 0.80  

N = 16 N. (perpendicular & upward to the plane )

Here Applied Force, P = 20N (which is down along the plane)

Now For Final Speed, We know the formula:-

v = u + at

v = 0 + 10 × 1

v = 10 m/s

the Distance travelled s = ut + 0.5 at×t

s = 0 + 0.5 ×10×1×1

s = 5 m.

Now,

(a)     So work done by the force of gravity in 1 sec. = F × d

             ⇒20 N × 5m      

             ⇒100 J.

(b) Here the weight act as downward, so distance travelled in downward.

             ⇒5 × sin37

             ⇒5 × 0.6  

             ⇒3 m.

so work done by gravity,

               ⇒20 N × 3 m

              ⇒60 J.

(c) Now, work done by all the forces  

               ⇒change in Kinetic energy

  ⇒

2

1  m(v2

−u  2

)

⇒0.5×2.0×(10  2

−0  2  )

⇒ 100 J.

⇒W.D by frictional force  

                 = work was done by all forces -( work was done by Normal force + work done by applied force + work done by gravity )  

                 = 100 J - (100 + 60 +0 )

                 = 100 - 1

     Hope this helps you≅        

Answer:

The Sun's gravitational pull keeps our planet orbiting the Sun. The motion of the Moon is affected by the gravity of the Sun AND the Earth. The Moon's gravity pulls on the Earth and makes the tides rise and fall every day. As the Moon passes over the ocean, there is a swell in the sea level.

Explanation:

The statement of factor that keeps Earth in orbit around the Sun is "the gravitational pull of the Sun."

The Sun is the primary star of our Solar System. The Earth revolves around our Sun, which really is a star. At a distance of around 93 million miles from the Sun, Earth is the third planet.

The fundamental force that governs the planets' orbits around the sun is gravity. While each planet does have its own gravity, which is determined by its size and speed of movement, orbit is determined by the gravity of the sun.

Our planet orbits the Sun due to it's gravitational pull. The Sun, as well as all of the planets and moons, are gravitationally bound together and circle all around solar system's centre of gravity.

The Sun's gravity is around 27.9 times that of Earth's, and it helps to govern the tides on Earth in a modest degree.

Hence the correct answer is the gravitational pull of the Sun.

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Answer:

c I think but that's only what i think

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 24.088×10²³ atoms of carbon are in sample containing 4.000 moles of carbon. The correct option is option B.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

Mathematically,

number of atoms/molecules/ formula units of carbon= number of moles of carbon × 6.022×10²³

number of moles of carbon= 4 moles

substituting all the given values in the above equation, we get

number of atoms/molecules/ formula units of carbon= 4 × 6.022×10²³

number of atoms/molecules/ formula units of carbon=2.4088×10²⁴ atoms of carbon

There are 2.4088×10²⁴ atoms of carbon

Therefore, 24.088×10²³ atoms of carbon are in sample containing 4.000 moles of carbon. The correct option is option B.

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Answer:

Conduction, Convection, and Radiation

Explanation:

I got it right on Edge 2021

the The fill in the blanks should be filled with Conduction, Convection, and Radiation

information regarding heat:

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Answer:

One orientation

Explanation:

A s orbital is a sphere like shape that surrounds the atomic nucleus that consists of electrons that can be found at the highest or lowest region of the orbital. S orbitals only consist of "one orientation" and is commonly mistaken by the p orbital because the p orbital also consists of electrons that can be found the most.

Hope this helps.

Answer:

Electromagnets are widely used as components of other electrical devices, such as motors, generators, electromechanical solenoids, relays, loudspeakers, hard disks, MRI machines, scientific instruments, and magnetic separation equipment.

Explanation:

Hope this helps :)

(didn't get this from the internet)

Answer:A higher effective nuclear charge causes greater attractions to the electrons, pulling the electron cloud closer to the nucleus which results in a smaller atomic radius. Down a group, the number of energy levels (n) increases, so there is a greater distance between the nucleus and the outermost orbital.

Answer:

A higher effective nuclear charge causes greater attractions to the electrons, pulling the electron cloud closer to the nucleus which results in a smaller atomic radius. Down a group, the number of energy levels increases, so there is a greater distance between the nucleus and the outermost orbital.Explanation:

Answer:

transform battery

Explanation:

Answer: D. Transform Boundary

Explanation: I did the test.

Answer:

Mass of solute = 0.0036 g

Explanation:

Given data:

Concentration of Cl⁻ = 15.0 ppm

Volume of water = 240 mL

Mass of Cl⁻ present = ?

Solution:

1 mL = 1 g

240 mL = 240 g

Formula:

ppm = mass of solute / mass of sample ×1,000,000

by putting values,

15.0 ppm = (mass of solute / 240 g) ×1,000,000

Mass of solute = 15.0 ppm ×  240 g / 1,000,000

Mass of solute = 0.0036 g

The atomic number of this atom : 8

Given

Atomic model (attached)

Required

The atomic number

Solution

To determine the atomic number of an element, we can look at the number of electrons or the number of protons, because

atomic number = number of protons = number of electrons in neutral atoms

While the mass number is the number of neutrons + the number of protons located in the atomic nucleus

The charge of each of these atomic sub particles:

If we look at this atomic model, there are 8 electrons in the shell, consisting of 2 electrons in the first shell and 6 electrons in the second shell (which can also be called valence electrons)

Whereas in the atomic nucleus there are 8 protons and 10 neutrons

Answer:8

Explanation:

The element with the electron configuration, 1s2 3s2 3p6 3s2 3p6 3d6 4s2, will be iron.

In the electronic configuration of elements, the number of electrons possessed by the element is shared into the orbitals according to their energy levels.

The electrons are first shared in orbitals in the same energy level before pairing starts.

Also for neutral atoms, the number of electrons is equivalent to the number of protons. The number of protons in itself represents the atomic number of elements.

Thus, considering this electron configuration, 1s2 3s2 3p6 3s2 3p6 3d6 4s2; the total number of electrons in all the orbitals is 26. The element with the atomic number of 26 is iron.

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Explanation:

Intermolecular forces are electrostatic in nature and include van der Waals forces and hydrogen bonds. ... The three major types of intermolecular interactions are dipole–dipole interactions, London dispersion forces (these two are often referred to collectively as van der Waals forces), and hydrogen bonds.May 20, 2018

Answer:

1. solute dissolved in solvent makes up a solution.

Answer:

I dont get it what am i supposed to do?

Explanation:

Answer:

Diamond

Explanation:

Answer:

0.97 atm.

Explanation:

From the question given above, the following data were obtained:

Final pressure (P2) = 6.8 atm

Initial temperature (T1) = 40 K

Final temperature (T2) = 280 K

Initial pressure (P1) =?

Thus, we can obtain the initial (original) pressure of the gas as follow:

P1/T1 = P2/T2

P1 /40 = 6.8/280

Cross multiply

P1 × 280 = 40 × 6.8

P1 × 280 = 272

Divide both side by 280

P1 = 272/280

P1 = 0.97 atm

Therefore, the original pressure of the gas is 0.97 atm.

Explanation:

yup,it is correct:-)

Answer:

the genotype would be 50% Rr and 50% rr

the phenotypes would be 50% Red flower (Rr) and 50% white flower (rr)

Explanation:

The spontaneous reactions are said to be exothermic in nature. Hence, option B is correct.

The type of reaction that has not been utilizing energy input output to the reaction system in order to favor the formation of product are termed as exothermic reaction.

The entropy has been the tendency of the randomness of atoms in the system, and the enthalpy has been the energy of the system.

With the spontaneous reaction, there has been an increase in the entropy of the system with the formation of the products, and a decrease in the enthalpy. The reaction forms no use of the input energy, and thereby cannot be endothermic in nature.

Therefore, the reaction that is exothermic tends to be spontaneous reactions. Hence, option B is correct.

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Answer:

Roman numeral notation indicates charge of ion when element commonly forms more than one ion. For example, iron(II) has a 2+ charge; iron(III) a 3+ charge.

Explanation:

Answer:

B

Explanation:

The second one is not balanced correctly.

2 NaOH + 2HNO3 → 2NaNO3 + 2 H20

I didn't notice this before but it can be balanced without the twos.

 NaOH + HNO3 → NaNO3 +  H20

It was still wrong. It needed to have the twos removed, not 2 more added. Adding two more isn't wrong, but it should be balanced without 2s if at all possible.

Answer:

B

Explanation:

it is B because in order to have kinetic energy the object has to be in motion, because if it wasnt in motion and sitting on the hill then it has potentail energy, hope this helps

Answer:

a.Neon

b.carbon

c potassium

Answer:

The polar covalent bond is much stronger in strength than the dipole-dipole interaction. The former is termed an intramolecular attraction while the latter is termed an intermolecular attraction. So now we can define the two forces: Intramolecular forces are the forces that hold atoms together within a molecule.

Explanation:

I have some things to point out:

#1: There is no such thing as "Dipole-dipole bonds", only Dipole-dipole interactions between molecules that share an unequal balance of electrons between their atoms.

#2: Intermolecular forces of attraction such as Dipole-dipole interactions are not considered as covalent bonds. Covalent bonds are rigid and are considered intramolecular forces of attraction (found within the molecule instead of between)

Hope I have helped you! Many thanks.