I need help please #4

Answer:

velocity ratio is defined as the ratio of distance moved by effort and load in the same time interval

Explanation:

Answer:

8.13 ×10²³ atoms

Explanation:

Given data:

Mass of magnesium = 32.45 g

Number of atoms = ?

Solution:

Number of moles of Mg:

Number of moles = mass/molar mass

Number of moles = 32.45 g/ 24 g/mol

Number of moles = 1.35 mol

Number of atoms:

1 mole contain 6.022×10²³ atoms

1.35 mol × 6.022×10²³ atoms/ 1mol

8.13 ×10²³ atoms

Given :

Volume of stock solution, [tex]V_s = 20\ mL[/tex].

Volume of diluted solution, [tex]V_d = 400 \ mL[/tex].

Molarity of diluted solution, [tex]M_d = 1.44\ M[/tex].

To Find :

The concentration of the stock solution.

Solution :

We know, dilution factor is given by :

[tex]D.F=\dfrac{V_ {diluted}}{V_{stock}}[/tex]      ....1)

and [tex]D.F= \dfrac{M_{stock}}{M_{diluted}}[/tex]     ....2)

Putting volume in above equation, we get :

D.F = 400/20

D.F = 20

Putting value of D.F in equation 2) we get :

[tex]\dfrac{M_{stock}}{M_{diluted}} = 20\\\\M_{stock} = 20\times 1.44\\\\M_{stock} =28.8\ M[/tex]

The concentration of stock solution is nearest to 30 M.

Therefore, the correct option is 1) 30 M.

Answer:

i know right answer

Explanation:

let me explain

Answer:

a.)cations; free to move around

b.)cations; fixed in place

Answer:

The correct answer for this question would be B) Protons

Explanation:

I got it right on my test (Can I have brainlyest)

The wavelength-λ = 6.12 x 10⁻⁷ m

Radiation energy is absorbed by photons

The energy in one photon can be formulated as

[tex]\large{\boxed{\bold{E\:=\:h\:.\:f}}}[/tex]

Where

h = Planck's constant (6,626.10⁻³⁴ Js)

f = Frequency of electromagnetic waves

f = c / λ

c = speed of light

= 3.10⁸  m/s

λ = wavelength

The wavelength of radiation with a frequency of 4.9 ×10¹⁴/s :

[tex]\tt \lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{3.10^8}{4.9\times 10^{14}}\\\\\lambda=6.12\times 10^{-7}~m[/tex]

Answer:

A

Explanation:

I got it in a test

Answer:

Active transport is an active process. Thus, it requires energy. Whereas facilitated diffusion is a passive process and does not require energy.

Explanation:

ugh

Answer:

D

Explanation:

A The calcium chloride dissolves in solution

B The mass of the solution totals 20 g

C The temperature of the solution is 35 degrees

D The solution became lighter in color

The correct answer would be that the solution became lighter in color.

An increase in temperature can also be considered a sign of a chemical reaction but in this case, the dissolution of calcium chloride in water is in itself exothermic.

A change in the mass of the final solution could also be considered a sign of a chemical reaction but in this case, the total mass equals the addition of the individual masses of the reactant.

The dissolution of calcium chloride in water is not enough as evidence of a chemical reaction. Dissolution can be a physical change of which, the evaporation of the water would retrieve the solute.

A change in color, however, is one of the evidence to establish that a chemical reaction has occurred.

The correct option is D.

Answer:

When we kick the ball, the force we apply to it causes it to accelerate from a speed of 0 to a speed of dozens of kilometers per hour. When the ball is released from the foot, it begins to decelerate (negative acceleration) due to the force of friction that is exerted upon it (as we observed in the previous example).

Explanation:

Answer:

Decreases, increases

Explanation:

Depending on the number of electrons shared, covalent bonds may be single, double or triple. In  a single bond, two electrons are shared between bonding atoms. In a double bond, four electrons are shared between bonding atoms while in a tripe bond, six electrons are shared between bonding atoms.

The number of bonds is otherwise referred to as the bond order. The higher the bond order the higher the bond energy and the shorter the bond length. The bond length shortens due to an increase in the s character of the bond.

Answer:

Marble forms when a pre-existing limestone rock is heated to such extreme temperatures that the minerals grow larger and fuse together. With this in mind, a hard marble rock would be the perfect example of the inner core of Earth since its packed, and full of high heat levels.

Explanation:

Answer:

The ratio = 2 : 1

Explanation:

The options are;

A) The skater experiences acceleration both while skating in a straight line and while making her turn.

B) Because the skater does not change her direction or speed, she does not experience acceleration.

C) The skater only experiences acceleration when she is turning.

D) The skater only experiences acceleration while skating in a straight line.

Answer:

A: The skater experiences acceleration both while skating in a straight line and while making her turn

Explanation:

We are told that She speeds up on the straight portion of the rink. This means that she experienced an acceleration since the speed was not constant but gradually increasing.

Also, we are told that She slows down near each end of the rink and then turns around. This means that she reduced speed before turning and it means there was also an acceleration as well when making the turn.

Thus, she experience acceleration both in the straight line and when making turn.

Option A is correct

Answer:

Explanation:

Digestion breaks down the food or nutrients taken in by the organism into a form of energy that is then transported to areas of the organism where it is needed. Along with transporting the waste to exit the organsim because the waste is no longer needed as digestion has extracted its nutrients.

Answer:

the advantage of using Microsoft Excel to create a graph, as opposed to pen and paper is it will help you get the right answer

Explanation:

Answer:

Electric Patterns and has many different variations.

Explanation:

Google

Answer:

3. Shared and unshared electron pairs repel each other as much as

possible

Explanation:

The variations in the bond angles of molecules and ions can be explained using the valence shell electron pair repulsion theory.

The VESPR model determines the total number of electron pairs (TEP) surrounding the central atom of a specie. The TEP consists of bond pairs BP and lone pairs LP.

All the electron pairs will orient themselves in such a way as to minimize the electrostatic repulsion between them.

The repulsion determines the geometry of the covalent bonds around the central atom. As the number of lone pairs increases from 0 to 2, the bond angles diminishes progressively.

Simple structure, diatomic, double bond, molecule. Hence, option C is correct.

A pure substance made up of two or more different elements combined chemically in a fixed ratio is called a compound.

[tex]O_2[/tex] is a covalent molecule because each oxygen atom needs two valence electrons to complete its octet. To meet this need each oxygen atom shares two of its electrons with the other oxygen forming a strong oxygen-oxygen double-shared covalent bond.

Hence, option C is correct.

Learn more about compounds here:

https://brainly.com/question/14782984

#SPJ2

Answer:

Oceanic crust, extending 5-10 kilometers (3-6 kilometers) beneath the ocean floor, is mostly composed of different types of basalts. Geologists often refer to the rocks of the oceanic crust as “sima.” Sima stands for silicate and magnesium, the most abundant minerals in oceanic crust. (Basalts are a sima rocks.) Oceanic crust is dense, almost 3 grams per cubic centimeter (1.7 ounces per cubic inch).

Oceanic crust is constantly formed at mid-ocean ridges, where tectonic plates are tearing apart from each other. As magma that wells up from these rifts in Earth’s surface cools, it becomes young oceanic crust. The age and density of oceanic crust increases with distance from mid-ocean ridges.

Just as oceanic crust is formed at mid-ocean ridges, it is destroyed in subduction zones. Subduction is the important geologic process in which a tectonic plate made of dense lithospheric material melts or falls below a plate made of less-dense lithosphere at a convergent plate boundary.

At convergent plate boundaries between continental and oceanic lithosphere, the dense oceanic lithosphere (including the crust) always subducts beneath the continental. In the northwestern United States, for example, the oceanic Juan de Fuca plate subducts beneath the continental North American plate. At convergent boundaries between two plates carrying oceanic lithosphere, the denser (usually the larger and deeper ocean basin) subducts. In the Japan Trench, the dense Pacific plate subducts beneath the less-dense Okhotsk plate.

Explanation:

Answer:

it is actually 45 points

Explanation:

Freezing rain melts in warm air and then freezes on cold surfaces while sleet refreezes before it hits the surface of Earth. Sleet is wet and rain is frozen. Freezing rain melts in warm air then refreezes before it reaches the surface, while sleet falls wet and freezes on the surface. you basically wrote out your answer yourself and you´re proof, i gooogled it, lol

Answer:

Freezing rain melts in warm air and then freeze then refreeze before it reaches the surface

Answer: Yes, they are.

Explanation:

Yes, they are. Li, Na, and K are referring to  Lithium, sodium, and potassium.

They are all belonging to the same group which is called the alkali metals group.

They are having the same number of valence electrons i.e. 1.

This group of the alkali metals are considering tree more metals in it which are Rb, Cs, and Fr.

Answer:

i dont have an answer for sure because it doesnt specify WHAT its energy chang occurs but i think its physical change

Explanation:

Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula. Chemical changes are also known as chemical reactions.

examples of chemical change:

burning a fire

boiling an egg

digestion

examples of physical change:

melting ice

rusting

breaking a pencil

hope i helped!!