Which of these describes why a stent is used? ​

Answer:

Well, if you check the reactivity series, calcium is more reactive than magnesium. This means there's a a trend of increasing reactivity as we go down the group. As beryllium is above magnesium, it must be the least reactive. Then magnesium is in the middle and the most reactive has to be calcium.

Answer:

Aluminium because highl elecronegativety element and more metalic hign melting and boling point from the other

Answer:

If electoral districting is left to incumbent legislatures, it becomes a tool to stack the political process against disempowered opponents

Explanation:

Answer:

+1/2

Explanation:

spin up is always +1/2

Answer:

a decrease in concentration affects the equilibrium

Explanation:

disturbance: equilibrium was disturbed by a decrease in concentration

response:system acts so as to increase concentration

reaction favoured: forward reaction

concentration: concentration of ...... ND ....... increases ND that of ......(product)decreases

Answer:

5. The coefficients are: 2, 7, 2, 4

6. The coefficients are: 1, 4, 1, 2

Explanation:

5. Balancing the equation.

__NO₂ + __H₂ —> __NH₃ + __H₂O

The above equation can be balance as illustrated below:

NO₂ + H₂ —> NH₃ + H₂O

There are 2 atoms of O on the left side and 1 atom on the right side. It can be balance by writing 2 before NO₂ and 4 before H₂O as shown below:

2NO₂ + H₂ —> NH₃ + 4H₂O

There are 2 atoms of N on the left side and 1 atom on the right side. It can be balance by writing 2 before NH₃ as shown below:

2NO₂ + H₂ —> 2NH₃ + 4H₂O

There are 2 atoms of H on the left side and a total of 14 atoms on the right side. It can be balance by writing 7 before H₂ as shown below:

2NO₂ + 7H₂ —> 2NH₃ + 4H₂O

Now the equation is balanced. Thus, the coefficients are: 2, 7, 2, 4

6. Balancing the equation:

__SiO₂ + __HF —> __SiF₄ + __H₂O

The above equation can be balance as illustrated below:

SiO₂ + HF —> SiF₄ + H₂O

There are 4 atoms of F on the right side and 1 atom on the left side. It can be balance by writing 4 before HF as shown below:

SiO₂ + 4HF —> SiF₄ + H₂O

There are 4 atoms of H on the left side and 2 atoms on the right side. It can be balance by writing 2 before H₂O as shown below:

SiO₂ + 4HF —> SiF₄ + 2H₂O

Now the equation is balanced. Thus, the coefficients are: 1, 4, 1, 2

Answer:

C

Explanation:

d=300

t=6hr

speed=?

speed=300/6

speed=50m/hr the important thing in this question is to get the right units

Answer:

parietal pleura

Explanation:

The pleurae, which are serous membranes, divide the thoracic cavity's wall from the lungs. The parietal pleura covers the interior of the thorax, mediastinum, and diaphragm, while the visceral pleura covers the surface of the lungs.

The perianal pleura, the outer layer, is attached to the chest wall. The lungs, mediastinum's neurovascular structures, and bronchi are all covered by the inner layer (visceral pleura).

The pleura's role in breathing is to enable the lungs to expand and collapse as efficiently as possible.

The parietal and visceral pleura can move over one another without rubbing against one another thanks to the pleural fluid's lubricating properties. The pleural layers themselves produce this fluid.

Therefore, parietal pleura, which surround the lungs in thoracic cavity.

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Answer: The theoretical yield of alum is 12.09 g

Explanation:

Molarity is calculated by using the equation:

[tex]\text{Molarity}=\frac{\text{Moles}}{\text{Volume}}[/tex] ......(1)

We are given:  

Molarity of sulfuric acid = 9.9 M

Volume of solution = 8.3 mL = 0.0083 L (Conversion factor: 1 L = 1000 mL)

Putting values in equation 1, we get:

[tex]\text{Moles of sulfuric acid}=(9.9mol/L\times 0.0083L)=0.08217mol[/tex]

The given chemical equation follows:

[tex]2Al+2KOH+4H_2SO_4+22H_2O\rightarrow 3H_2+2KAl(SO_4)_2.12H_2O[/tex]

By the stoichiometry of the reaction:

4 moles of sulfuric acid produces 2 moles of alum

So, 0.08217 moles of sulfuric acid will produce = [tex]\frac{2}{4}\times 0.08217=0.0411mol[/tex] of alum

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(2)

Molar mass of alum = 294.24 g/mol

Plugging values in equation 2:

[tex]\text{Mass of alum}=(0.0411mol\times 294.24g/mol)=12.09g[/tex]

Hence, the theoretical yield of alum is 12.09 g

Answer:

boron sulfide

b=boron

s=sulfer

Explanation:

Answer:

D. The energy in light waves comes in units called photons.

Explanation:

its known as quatum theory

Answer:

26.85 grams

Explanation:

The formula for mole calculations is number of moles = given mass/gram-formula mass.

The number of moles is given to us, which is 0.125.

The gram formula mass of SnSO4 is about 214.77.

Plug in the values we have into the equation. It should look like this:

0.125 = x / 214.77

Solve for x by multiplying 214.77 and 0.125. The answer should be about 26.85 grams.

Answer:

A FUSE is a type of conductor which protects the circuit by shorting it down when there is excess flow of current passing through it.

Explanation:

A fuse wire is made up of conducting materials such as alloy of tin and lead that has high resistivity. It has a low melting point of 200°C. It works based on the principle of heating effect of electric current. The functions of fuses include the following:

--> Fuses are made up of thin wire CONDUCTORS which interrupts or breaks the current flow of a circuit when in excess, thereby protecting the circuit from damage.

--> it prevents overload of current. In the event where too many appliances are connected to a single circuit, this can lead to overload which triggers a fuse to terminate the circuit connection.

--> It prevents total black-out: SWITCH-LIKE devices known as CIRCUIT BREAKERS share this function with the fuses. The nearest circuit breaks if any dysfunction occurs in the components of the circuit thereby preventing blackout.

Answer:

When heated, oxygen reacts with copper to form copper oxide. If this reaction occurs in a sealed container, will the mass of the container and everything in it increase, decrease, or stay the same and why? The mass will increase because a new kind of molecule is formed.

Explanation:

As above, carbonates decompose upon heating to give the metal oxide and carbon dioxide. The mass is lost as carbon dioxide.

To solve this we must be knowing each and every concept related to mass. Therefore, Carbon dioxide is released as the mass is depleted when carbonates are heated.

Mass defines the quantity of a substance. It is measured in gram or kilogram. Average mass is the mass of atoms of an element that are isotopes.

When copper was heated in the air, the resulting solid product has a larger mass than the initial copper. When calcium carbonate was heated in air, the resulting solid product has much less mass than the initial calcium carbonate. When carbonates are heated, they breakdown into metal oxides and carbon dioxide. Carbon dioxide is released as the mass is depleted.

Therefore, Carbon dioxide is released as the mass is depleted.

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Answer:

0.0036 moles of NaOH are present

Explanation:

A solution of 0.1mol/dm³ contains 0.1 moles of solute (In this case, NaOH), per 1 dm³ of solution.

36cm³ are in dm³ (1000cm³ / 1dm³):

36cm³ * (1dm³/1000cm³) = 0.036dm³

The moles are:

0.036dm³ * (0.1mol/dm³) = 0.0036 moles of NaOH are present

Answer:

2SO2 + O2 → 2SO3

Explanation:

According to this question, sulphur dioxide (SO2) reacts with oxygen to produce sulphur trioxide (SO3). The equation is as follows:

SO2 + O2 → SO3

The above equation is unbalanced because there are unequal number of atoms of each element in the both reactants and products. To balance the equation, we use coefficients to make the number of atoms equal. The balanced equation is as follows:

2SO2 + O2 → 2SO3

- There are 2 moles of S on both sides of the equation.

- There are 4 moles of Oxygen on both sides of the equation.

Answer: 287.46 billion km

Explanation: calculated it myself. nah but thats the answer

Answer:

Stars have the different colors that make up white light, the color of a star is related to the wavelength of the light which is emitted by the star which is related to the temperature of the star's surface

Very hot temperatures yield hotter wavelength, which light having short wavelength being bluish,  the blue and blue-white stars are the hottest stars, while stars which emit longer wavelength and therefore have a color of brown and red have a cooler surface temperature

The surface temperature of a star also has an effect on the bright appearance of a star. The higher the temperature of a star the higher the heat energy given off and the brighter the star will be, as a star that gives off more energy is brighter than one that gives less energy

Explanation:

Answer:

Explanation:

(a) Firstly, caesium abd potassium are both in Group 1 of the periodic table. Group 1 metals (also called alkali metals) are the most reactive metals of the periodic table. Caesium is more reactive than Potassium because it has a higher electropositivity than Potassium. Electropositivity is the tendency of a metal to donate electron(s) to form a cation. Electropositivity increases down the group; this is because it is easier for atoms to loose electrons on the outermost shell that are far away from the central nucleus as against atoms whose outermost electrons are closer to the central nucleus. Thus, the more "bulky" an atom is, the farther it's outermost electrons (valence electrons) get from the central nucleus and the easier it is to lose the outermost electron(s). And the easier it is for the valence electron(s) to be removed, the more reactive the atom would be and vice-versa.

Caesium is more reactive than potassium because it is more bulky than potassium, with an atomic number of 55, while potassium has an atomic number of 19.  

NOTE: The closer an electron is to the nucleus, the more difficult it is to be removed from it's shell.

(b) i. Formula for Caesium Nitrate:

Symbol for Caesium is Cs and Nitrate is NO₃⁻.

Cs⁺ + NO₃⁻  ↔  CsNO₃

Formula for Caesium Nitrate is  CsNO₃

ii. Formula for Caesium sulphate

Symbol for caesium is Cs and Sulphate is SO₄²⁻

Cs⁺ + SO₄²⁻  ↔   Cs₂SO₄  

Formula for Caesium sulphate is Cs₂SO₄

NOTE: When writing the formulae, the charges would be exchanged to form the subscript as seen on the product sides above.

Answer:

C. Gravity only

Explanation:

Answer:

Barium Hydroxide

Explanation:

..........................

Answer:

A.) is the correct answer

The continuation of the electronic configuration would be 3p6, 4s2, 3d4

The initial p-orbital (the 3p3) is incompletely filled. Thus, the first thing would be to fill it completely (3p6) so as to obey the orbital-filling rule. This leaves 6 more electrons

After 3p orbital, the next orbitals are 4s, 3d, 4p, 5s, etc.

The 4s orbital will take a maximum of 2 electrons, leaving 4 more electrons.

Next would be the 3d orbital which can take a maximum of 8 electrons, but only 4 electrons are left.

Thus, the electronic configuration would be 3p6, 4s2, 3d4.

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Answer:

[tex]C_3H_6[/tex]

Explanation:

¡Hola!

En este caso, basado en la información dada, es posible calcular las moles de carbono en el compuesto al usar la masa molar del CO2 y la siguiente relación molar:

[tex]n_C=0.660gCO_2*\frac{1molCO_2}{44.01gCO_2}*\frac{1molC}{1molCO_2}=0.015molC[/tex]

Ahora, calculamos las moles de hidrógeno restando la masa de carbono de la de la muestra basado en el siguiente factor molar:

[tex]m_{H}=0.210g-0.015molC*12.01gC/molC=0.030molH[/tex]

Entonces la formula empírica del compuesto resulta:

[tex]CH_2[/tex]

Dado que el carbono y el hidrógeno están en una relación 1:2. Ahora bien, calculamos la masa molar del gas considerando la presión, densidad y temperatura del mismo:

[tex]PV=nRT\\\\PV=\frac{m}{MM}RT \\\\MM=\frac{m}{V}\frac{RT}{P}=\frac{dRT}{P}\\\\MM=\frac{1.87g/dm^3*0.08206\frac{atm*L}{mol*K}*273K}{1atm}=41.9g/mol[/tex]

Es decir que la fórmula molecular y la empírica están en una relación de 3, por lo que la fórmula molecular resulta:

[tex]C_3H_6[/tex]

¡Saludos!

Answer:

Bones aren't made of calcium metal. Bones are a collegun structure filled in with mostly calcium carbonate and some calcium phosphate

Answer:

Bones aren't made of calcium metal. Bones are a collegun structure filled in with mostly calcium carbonate and some calcium phosphate

Explanation:

I hope this helps

Answer:c6h14

Explanation:

Answer:

1) b. 4.38

2)  d. 10.7

Explanation:

1) The problem tells us that [H₃O⁺] = 4.2x10⁻⁵ M, and keeping in mind that [H₃O⁺]= [H⁺], we can calculate the pH of the solution:

2) First we calculate the pOH of the solution:

Then we calculate the pH using the following formula:

The pH of a solution with a concentration of 4.2x10⁻⁵ M H₃O⁺ ion is 4.38 and of a solution with a concentration of 4.6x10⁻⁴ OH⁻ ion is 10.7.

pH of any solution is define as the negative log of the concentration of H⁺ ions and pOH is define as the negative log of the concentration of OH⁻ ions.

Given that concentration of H⁺ ions in solution = 4.2x10⁻⁵ M

pH for this solution is calculated as:
pH = -log(4.2x10⁻⁵) = 4.38

Also given that concentration of OH⁻ ions in solution = 4.6x10⁻⁴

pOH = -log(4.6x10⁻⁴) = 3.33

We know that, pH + pOH = 14.

pH = 14 - 3.33 = 10.7

Hence, value of pH & pOH is 4.38 and 10.7 respectively.

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Answer:

2

Explanation:

Molar Mass of Al = 27

Molar Mass of S = 32

Molar Mass of O = 16

Putting the molar mass value in Al2 (SO4) 3

27 x 2 + 3 ( 32 + 16 x 4)

54 + 3 ( 32+ 64)

54 + 3 x 96

54 + 288

342