Help i dont get it

Answer:

The answer is letter D. 0./75 mol

Explanation:

Explanation: It's a 3.0 M solution so 1 litre of solution contains 3 moles of NaOH. 250 ml of solution therefore contains 0.25 x 3 = 0.75 moles of NaOH.

Answer:

it is the element cobalt with atomic number 27

Answer:

to identify the element by using flame tests

Taking into account the ideal gas law, the pressure is 2.52 atm.

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas are related by a simple formula called the ideal gas law. This equation relates the three variables if the amount of substance, number of moles n, remains constant. The universal constant of ideal gases R has the same value for all gaseous substances. The numerical value of R will depend on the units in which the other properties are worked.

P×V = n×R×T

In this case, you know:

Replacing in the ideal gas law:

P×500 L = 52.1 moles ×0.082 [tex]\frac{atmL}{molK}[/tex] ×295 K

Solving:

P= (52.1 moles ×0.082 [tex]\frac{atmL}{molK}[/tex] ×295 K)÷ 500 L

P= 2.52 atm

Finally, the pressure is 2.52 atm.

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1. The neutral atoms of lead has 82 protons.

2. The ions of lead also have 82 protons.

The correct answer to the question is Option D. Neutral atoms of lead must have 82 protons. Ions must have 82 protons, as well.

Lead, Pb is a metal with an atomic number (i.e proton number) of 82

Metals can only form ions by losing their valence electron(s)

NOTE: In the formation of ions, only the electrons are involved. The protons are not involved. Thus, the protons of the neutral atom and the ion remains the same.

With the above information in mind, we can conclude that neutral atoms of lead must have 82 protons. Ions must have 82 protons, as well.

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Answer:

C. Neutral atoms of lead must have 82 neutrons, but ions can have more or fewer

Explanation:

O Neutral atoms of lead must have 82 neutrons, but ions can have more or fewer. O Neutral atoms of lead must have 82 protons, but ions can have more or fewer.

If It takes 60mL of 0.20M of sodium hydroxide (NaOH) to neutralize 25 mL of carbonic acid ([tex]H_2CO_3[/tex]), then the concentration of the carbonic acid is 0.24M

The reaction between NaOH solution and [tex]H_2CO_3[/tex] is written below

[tex]2NaOH + H_2CO_3 \rightarrow Na_2CO_3 + 2H_2O[/tex]

Volume of NaOH, [tex]V_B[/tex] = 60 ml

Volume of [tex]H_2CO_3[/tex], [tex]V_A=25 ml[/tex]

Molarity of [tex]H_2CO_3[/tex], [tex]C_A=?[/tex]

Molarity of NaOH, [tex]C_B=0.20M[/tex]

Number of moles of [tex]H_2CO_3[/tex], [tex]n_A=1[/tex]

Number of moles of NaOH, [tex]n_B=2[/tex]

The mathematical equation for neutralization reaction is:

[tex]\frac{C_AV_A}{C_BV_B} =\frac{n_A}{n_B}[/tex]

Substitute  [tex]C_B=0.2 M[/tex],  [tex]n_A=1[/tex],  [tex]n_B=2[/tex],  [tex]V_B[/tex] = 60ml, and  [tex]V_A=25 ml[/tex] into the equation above in order to solve for [tex]C_A[/tex]

[tex]\frac{C_A \times 25}{0.2 \times 60}=\frac{1}{2} \\\\50C_A=12\\\\C_B=\frac{12}{50} \\\\C_B=0.24M[/tex]

Therefore, the concentration of the carbonic acid is 0.24M

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Answer:

A

Explanation:

asteroids most often leave trails due to the large amount of friction that occurs.

The bright spatial object with a tail moving fastly across the sky is called a comet. Comets are made of rock, dust and ices.

Comets are orbiting snowballs around sun made of frozen gases, rock, and dust. They enlarge to the size of a sizable town when frozen. A comet heats up and ejects dust and gases into a huge, blazing head that is larger than most planets when its orbit puts it near to the Sun.

Millions of kilometers away from the sun, the dust and gas combine to form a tail. The Kuiper Belt and much further Oort cloud are presumably home to billions of comets that orbit our sun.

Some of their ice begins to melt and boil off as the comet approaches the sun, along with some dust. The coma, which is created by these particles and gases, surrounds the nucleus.

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Insects can walk on water due to its surface tension, which is something like 0.07 J/m^2.

So water (and most liquids) have a property called surface tension, which is defined as the amount of energy that you need to increase the surface per area unit of the liquid volume.

Thus, if the insect has smaller energy than that, it would not change the surface of the liquid, allowing it to walk on the water's surface.

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Answer: They are able to walk on water because of surface tension. Liquid molecules are held together by electrostatic forces. Molecules on the surface of the water are attracted to surrounding molecules and tension is created as the molecules get pulled down. This allows them to distribute their body weight over the water’s surface without breaking through that force.

Explanation:

Answer:

Vitamin C is water-soluble and not stored in your body

In contrast to fat-soluble vitamins, water-soluble vitamins do not get stored within the body. Instead, the vitamin C that you consume gets transported to your tissues via body fluids, and any extra gets excreted in urine ( 1 ).

Answer:

The reason vitamin C isn't stored well is because your body can't make it, and vitamin C is a water-soluble vitamin. This means it dissolves in water, and what your body doesn't use right away is excreted through urine. Thus, it is not stored in our body to a significant extent.

Explanation:

I hope it help u =)

Brainliest answer pls

Answer:

ZH² + O² = ZH²O I think this may help you I don't really know how to explain

Answer:

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

30.973761

Answer:

The setup above is used to collect hydrogen gas

Both filtration and distillation are useful ,methods to purify or separate components of a mixture. To collect soluble gas such as ammonia the best method is distillation. Thus setup 2 is better for collection of solute.

Distillation is the process of separation of compounds using  heat and condenser. The mixture is first boiled to the boiling point of solvent. When it is heated the solvent such as water passes from the beaker on which the mixture is taken.

The steam of the solvent is then cooled in the condenser tube and then liquid is collected to a second beaker. Therefore, the solute remains in the first beaker and can be collected.

Using filtration, we can only separate solution with insoluble solutes. Using filter paper the solid from the solution can be separated out.

First set up shows the filtration method  which is not applicable for collecting soluble gas like ammonia. Therefore, the second setup that is distillation is better to collect soluble gases.

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The Coriolis Effect (Core-nol-e-us)

Answer: Neutral Xe atom

Answer:

Fr

Explanation:

I took the test

Answer:

False

Explanation:

Fluid pressure has no direction, being a scalar quantity, whereas the forces due to pressure have well-defined directions: They are always exerted perpendicular to any surface. The reason is that fluids cannot withstand or exert shearing forces.

Answer:

Explanation:

7A 0.2

7B cork

7C  Yes because the lighter it is the more likely it will float

7D  Density is one of the fundamental scientific principles of life. It can describe any everyday object. Despite its significance, students often struggle to understand what it really is. Density is a measurement of how much space or volume is packed in an object or substance.

8   property means a characteristic or trait that you can use to describe matter by observation, measurement, or combination.

Considering the Dalton's partial pressure, the correct answer is option a.: the total pressure of the mixture is 1.86 atm.

The pressure exerted by a particular gas in a mixture is known as its partial pressure. So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:

[tex]P_{T} =P_{1} +P_{2} +...+P_{n}[/tex]

where n is the amount of gases present in the sample.

This relationship is due to the assumption that there are no attractive forces between the gases.

In this case, a mixture contains 220 mmHg of CO, 350 mmHg of Ne and 840 mmHg of He. The total pressure of the mixture can be calculated as:

[tex]P_{T} =P_{CO} +P_{Ne} +P_{He}[/tex]

[tex]P_{T} =220 mmHg +350 mmHg+840 mmHg[/tex]

Solving:

[tex]P_{T}[/tex]= 1410 mmHg

Being 760 mmHg=1 atm, then:

[tex]P_{T}=1410 mmHgx\frac{1 atm}{760 mmHg}[/tex]

Solving:

[tex]P_{T}[/tex]= 1.86 atm

Finally, the correct answer is option a.: the total pressure of the mixture is 1.86 atm.

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The emf of the cell as written is calculated to be  0.014 V.

Using the Nernst equation;

Ecell = E°cell - 0.0592/n log Q

We must note that  E°cell = 0 because the anode and cathode are composed of the same type of metal.

Now;

Substituting values, we have;

Ecell = 0 -  0.0592/3 log (0.50 M)/(0.10 M)

Ecell = 0.014 V

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Answer:

Because of the two different parts of the molecule, a soap molecule is soluble in water and at the same time can dissolve fats. The fats are attracted to the non-polar tail part of the soap while the polar head makes the whole complex.

Explanation:

hope it helps

i think it's a simple covalent structure

Answer:

B

Explanation:

Periodic refers to properties that repeat at certain intervals. Click to see full answer. In respect to this, what does periodic mean in the term periodic table? In the context of chemistry and the periodic table, periodicity refers to trends or recurring variations in element properties with increasing atomic number.

One approach focuses on tradition, while the other focuses on the treatment of women in their culture the response is cultural value. Hence option A is correct.

Traditions are defined as a notion or practice  that has been passed down within a community or society and has unique importance or symbolic value that dates back in time. Traditions are notions and convictions that are passed down from generation to generation.

Cultural value are defined as the fundamental values and concepts that underpin a community's existence and provide a foundation for its protection and reliance on peaceful coexistence. Cultural values are the fundamental notions of right and wrong held by a culture.

Thus, one approach focuses on tradition, while the other focuses on the treatment of women in their culture the response is cultural value. Hence option A is correct.

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Answer: only culture value

Explanation: just answered it

The partial pressure of NO₂ at equilibrium is 0.70 bar and the partial pressure of N₂O₄, at equilibrium is 0.23 bar.

Let x be the mole fraction of NO₂ and x' be the mole fraction of N₂O₄.

The total pressure according to Dalton's law of partial pressure is the sum of the partial pressures of each gas.

Let P be the total pressure of the gases, P' be the partial pressure of NO₂ = 1.4 bar and P" be the partial pressure of N₂O₄ = 0.46 bar.

So, P = P' + P"

= 1.4 bar + 0.46 bar

= 1.86 bar

Since P' = xP

x = P'/P

= 1.4 bar/1.86 bar

= 0.753

Also, P" = xP

x' = P"/P

= 0.46 bar/1.86 bar

= 0.247

Now, since the volume of the container is doubled at constant temperature, we use Boyle's law to determine the new pressure. P₁.

Boyle's law states that the pressure of a given mass of gas is inversely proportional to its volume provided the temperature remains constant. It is written mathematicaly as PV = constant

So, PV = P₁V₁

P₁ = (V/V₁)P

Since V/V₁ = 1/2

P₁ = (V/V₁)P

P₁ = P/2

P₁ = 1.86/2 bar

P₁ = 0.93 bar

So, the new partial pressure of NO₂, P₂ = xP₁

= 0.753 × 0.93 bar

= 0.70 bar

The new partial pressure of N₂O₄, P₃ = x'P₁

= 0.247 × 0.93 bar

= 0.23 bar

So, the partial pressure of NO₂ at equilibrium is 0.70 bar and the partial pressure of N₂O₄, at equilibrium is 0.23 bar.

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Answer:

Explanation: Atomic weight is measured in atomic mass units (amu), also called daltons.

There are 6.44 × 10²³ molecules in 24.0 L of oxygen gas at standard temperature and pressure.

HOW TO CALCULATE NUMBER OF MOLECULES:

To calculate the number of molecules in a substance, we need the number of moles. The number of moles can be calculated using ideal gas law equation as follows:

PV = nRT

Where;

According to this question, oxygen gas is at standard temperature (273K) and pressure (1 atm)

1 × 24 = n × 0.0821 × 273

24 = 22.4n

n = 24 ÷ 22.4

n = 1.07moles

To calculate the number of molecules, we multiply the no. of moles by Avogadro's number (6.02 × 10²³)

no. of molecules = 1.07 × 6.02 × 10²³

no. of molecules = 6.44 × 10²³

Therefore, there are 6.44 × 10²³ molecules in 24.0 L of oxygen gas at standard temperature and pressure.

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Answer:

Cu(OH)₂

Explanation:

Hope that helps

Answer: The chemical formula is Cu(OH)₂