Please somone help me with a chemistry question brainliest to whoever answers correctly and 20 points

Answer:

A = 66.98 square in.

Explanation:

The Area of a sector is given by the formula

[tex]A = \frac{\theta}{360}\times \pi r^2[/tex]

here θ is the central angle and r is the radius

given that θ = 120° and radius =  8 inches

[tex]A = \frac{120}{360}\times3.14\times 8^2[/tex]

A = 66.98 square in.

Answer:

the value

Explanation:

Answer:

the pressure of a gas is directly proportional to its volume.

Explanation:

Robert Boyle was an Irish chemist and is famously referred to as the first modern chemist. He was born on the 25th of January, 1627 in Lismore, Ireland and died on the 31st, December 1691, London, United Kingdom.

Boyles states that when the temperature of an ideal gas is kept constant, the pressure of the gas is inversely proportional to the volume occupied by the gas.

Mathematically, Boyles law is given by;

[tex] PV = K[/tex]

[tex] P_{1}V_{1} = P_{2}V_{2} [/tex]

Where;

P1 is the original pressure.

P2 is the final pressure.

V1 is the original volume.

V2 is the final volume.

This ultimately implies that, ventilation which is typically governed by Boyle's Law, which states that at a constant temperature the pressure of a gas is directly proportional to its volume.

Answer:

ecological succession

Explanation:

Answer:

ecological succession

Explanation:

I did this before

Answer:

The volume of the helium balloon is 0.306 L.

Explanation:

Boyle's law states that the volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure. That is, if the pressure increases, the volume decreases, while if the pressure decreases, the volume increases.

Mathematically, Boyle's law indicates that the product of pressure and volume always has the same value:

P*V= k

Assuming that you have a certain volume of gas V1 that is at a pressure P1 at the beginning, by varying the volume of gas to a new value V2, then the pressure will change to P2, and it will be fulfilled:

P1*V1= P2*V2

In this case:

Replacing:

2 atm* 0.15 L= 0.97 atm* V2

Solving:

[tex]V2= \frac{2 atm* 0.15 L}{0.97 atm}[/tex]

V2= 0.306 L

The volume of the helium balloon is 0.306 L.

Answer:

acid

Explanation:

Answer:

2.05 L is the correct answer.

Explanation:

w = 64 g

c = 0.420 M

m = 40 + (16+1)×2 = 74

[tex]c = \frac{w}{m \times v} \\ \implies \: v = \frac{w}{c \times m} \\ = \frac{64}{0.420 \times 74} \\ = 2.05 \: \: liters[/tex]

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The volume of the solution is given below which can be calculated using the molarity formula.

d. 2.18 litres

It is defined as the ratio of number of moles of solute to the volume of the solution.

It is given by:

M= n/V

What information do we have?

M= 0.420M

mass = 64.0 grams

Molar Mass= 74g/mol

To find:

Volume of solution=?

Calculation for number of moles:

n= m/ M

n= 64/70

n= 0.91 moles

Molarity=  n/V

0.420 M= 0.91 moles /V

V= 0.91/ 0.420

V= 2.1768 litres

Thus, the volume of the solution is 2.18 litres.

Find more information about Molarity here:

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Answer:

The ratio of atoms of potassium to atoms of oxygen is  2:1

Explanation:

As the equation given is :

The product formed is 2 moles of potassium oxide .

Amount of potassium atom in the potassium oxide  is 2 atoms of potassium and amount of oxygen atom present here is 1 atom of oxygen .

But we have 2 moles of potassium oxide . So, the potassium and oxygen atoms will be multiplied by 2 .

Hence , we get 4 atoms of potassium and 2 atoms of oxygen .

Ratio of potassium to oxygen atoms is -   4:2

Therefore ,   2:1

Answer:

2;1

Explanation:

Answer:

[He] 2s²

Explanation:

Answer:

42 L

Explanation:

de los parámetros en la pregunta;

V1 = 358L

T1 = 152 ° C + 273 = 425 K

P1 = 470 mmHg × 1 atm / 760 mmHg = 0.6atm

V2 =?

P2 = 6 atmósferas

T2 = 500 K

P1V1 / T1 = P2V2 / T2

P1V1T2 = P2V2T1

V2 = P1V1T2 / P2T1

V2 = 0,6 × 358 × 500/6 × 425

V2 = 107400/2550

V2 = 42 L

Answer:

1.28 g

Explanation:

Mass of anhydrous compound/molar mass of anhydrous compound = mass of hydrated compound/ molar mass of hydrated compound

Mass of anhydrous compound = ?

Mass of hydrated compound = 2g

Molar mass of anhydrous compound= 160 g/mol

Molar mass of hydrated compound = 250 g/mol

x/160 = 2/250

250x = 2 ×160

x= 2 × 160/250

x= 1.28 g

Answer:

this link not hacl belive me

https://www.flinnsci.com/api/library/Download/18ce587821c24fb3b0ad7d878bd6a3d9Explanation:

Answer: The reaction proceeds in the backward direction.

Explanation:

A buffer is a solution that maintains the pH of the solution and resists any significant changes of pH on the addition of acid or alkali.

A buffer solution of [tex]NH_4Cl\text{ and }NH_3[/tex] is prepared. It is a basic buffer as it is formed by the combination of a weak base [tex](NH_3)[/tex] and its conjugate acid [tex](NH_4Cl)[/tex]

When a strong base (NaOH) is added to this buffer solution, the ammonium ions releases hydrogen ion to the solution which then combines with the hydroxide ions to form water and ammonia in a solution. Thus, maintaining the pH of the buffer.

The given chemical equation follows:

[tex]NH_3(aq)+H_2O(l)\rightleftharpoons NH_4^+(aq)+OH^-(aq)[/tex]

Hence, the reaction will proceed in the backward direction.

When NaOH is added to this buffer solution it forms water and ammonia.

A buffer is a solution that maintains the pH of the solution and maintains the pH on the addition of acid or alkali.

A buffer solution of [tex]NH_4Cl[/tex] and [tex]NH_3[/tex] is is a basic buffer as it is formed by the combination of a weak base and its conjugate acid.

When a NaOH which is a strong base is added to this buffer solution, the ammonium ions release hydrogen ion which combines with the hydroxide ions to form water and ammonia helps maintain the pH of the buffer.

Learn more:

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Answer:

B

Explanation:

because HCl donates a proton to water. Therefore, HCl is an acid. H2O accepts a proton from HCl. Therefore, H2O is a base.

Answer: Out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.

Explanation:

A change that leads to the change in chemical composition of a substance is called a chemical change.

For example, [tex]2NH_{3} \rightarrow N_{2} + 3H_{2}[/tex]

Here, bond between the reactant atoms nitrogen and hydrogen is broken down.

On the other hand, bond connecting the products that is [tex]N_{2}[/tex] and [tex]H_{2}[/tex] is formed.

Thus,, we can conclude that out of the given options bonds connecting atoms in reactants break, and bonds connecting atoms in products form are the changes which takes place when a chemical change occurs.

Answer:

A P wave can move through solid rock only. P wave can travel through liquid accurately describes a P wave.

Answer:

It is an ionic compound that consists of one calcium cation Ca2+ and two chlorine anions. The bivalent calcium metal forms an ionic bond with two chlorine atoms. The formation of cacl2 happens mainly by reacting limestone (CaCo3) with hydrochloric acid (HCl).

Answer:

You are moving because the Earth and everything in our solar system is constantly moving. ... As the Earth rotates, it also moves, or revolves, around the Sun. The Earth's path around the Sun is called its orbit. It takes the Earth one year, or 365 1/4 days, to completely orbit the Sun.

Answer:

um lol i think you mean  Why does the earth revolve around the sun

its because the  that the gravity of the Sun keeps the earth  in its orbit  

Explanation:

hope this helps!

Answer:

CaC0³ scientific name is Calcium carbonate

Explanation:

Have a great summer :)

Answer:

9

Explanation:

I took the same test :)

The stoichiometry is important in chemistry which helps us to use the balanced equation to calculate the amount of reactants and products. Here the moles of hydrogen needed is 9. The correct option is B.

The quantitative study of the reactants and products involved in a chemical reaction is known as the chemical stoichiometry. The stoichiometric coefficients can be fractions including the whole numbers.  It helps to establish the mole ratio.

The stoichiometric coefficient is basically the number which is present in front of the atoms, molecules or ions. The stoichiometric calculations are also used in gravimetry and volumetry.

Here the balanced equation for the reaction is:

N₂ + 3H₂ → 2NH₃

Number of moles of H₂ = 3 mol N₂× 3 mol H₂  / 1 mol N₂ = 9 mol H₂

So the number of moles of H₂ is 9.

Thus the correct option is B.

To know more about stoichiometry, visit;

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Despite its appearance, air has a ‘thickness’ so when the sun is high in the sky the light travels through the air on a very much shorter path than when it is low on the horizon.

Imagine that air water and you are below the surface, the light from an overhead sun will be quite sharp and bright, but if lower in the sky it will have to travel through much more water to reach you, so will look less bright and sharp. It ma not seem the same, but the atmosphere is just like very thin water, and a low lying sun will be drastically reduced in strength, so all you will see is a sun with a shift to the red end of the spectrum as all the actinic part will be filtered away by that thicker atmosphere.

Answer:

2.5moles of Fe(OH)3

Explanation:

i don't know how to explain this

Answer:

Nucleus and mitochondria. Organism.

Explanation:

The two main organelles are the nucleus and the mitochondria . The nucleus is boss of the factory(controls everything). The mitochondria is the power house of the cell (provides the energy). Humans are organisms (made of organs systems working together) . Another example is plants they are also organisms

Answer:

The answer is c

Answer:

Li is more reactive then Be.

Explanation:

As you go to the farther left and down on the periodic table, the higher that element reactivity is.