What volume of 6.9 M NaOH is needed to completely titrate 0.42 L of 2.39 M phosphoric acid according to
the equation:

H3PO4(aq) + 3NaOH(aq) + Na3PO4(aq) + 3H2O(aq)

A) O 0.05 L
B) O6.93 L
C) O0.44 L
D) 03.01 L
E) 436.43 L

Using Charles law

[tex]\boxed{\sf \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}}[/tex]

[tex]\\ \sf\longmapsto V_1T_2=V_2T_1[/tex]

[tex]\\ \sf\longmapsto 1(40)=27V_2[/tex]

[tex]\\ \sf\longmapsto V_2=\dfrac{40}{27}[/tex]

[tex]\\ \sf\longmapsto V_2=1.48\ell[/tex]

Answer:

Chromosome condensation, the landmark event at the onset of prophase, often begins in isolated patches of chromatin at the nuclear periphery. Later, chromosome condense into two threads termed sister chromatids that are closely paired along their entire lengths.

Explanation:

hope dis help & may I have brainly plz

Answer:

The two carbon atoms share a total of six electrons with each other.

Explanation:

Looking at the structure of the molecule H-C≡C-H as shown in the question, we will notice that there exists a triple bond between the two carbon atoms.

Each bond between the two carbon atoms represents two electrons shared. Since there are three bonds between the two carbon atoms, then a total of six electrons were shared between the two carbon atoms hence the answer chosen above.

Answer:

Solar heating of the Earth's surface is uneven because land heats faster than water, and this causes air to warm, expand and rise over land while it cools and sinks over the cooler water surfaces.This differential heating is passed on to the air above by conduction which causes air expansion and changes in pressure.

Answer:

-401.06 atm

Explanation:

Applying,

P = (nRT/V-nb)-(an²/V²)............... Equation 1

Where P = Pressure, R = Universal gas constant, V = molar Volume, T = Temperature in Kelvin, a = gas constant a , b = gas constant b, n = numbers of mole

From the question,

Given: T = 299.8 K, V = 0.8006 L, a = 2.318 L.atm/mol, b = 3.978×10²L/mol

Constant: R = 0.0082 atm.dm³/K.mol

Substitute these values into equation 1

P = [(0.0082×299.8×10.53)/(0.8006-(10.53×397.8)]-[(10.53²×2.318/0.8006²)]

P = (25.89/-4188.0334)-(400.995)

P = -0.0618-400.995

P = -401.06 atm

Answer:

[tex]\boxed {\boxed {\sf -2}}[/tex]

Explanation:

We are asked to find the net charge of an ion.

The ion has 14 protons, 16 electrons, and 12 neutrons. Recall the charges of each subatomic particle.

Neutrons are neutral and have no charge, so we can ignore them while finding the net charge. There are 14 protons and 16 electrons.

14 protons and 14 electrons have a net charge of 0 because the charges balance each other out. However, we have 16 electrons, which is 2 more than 14. Each electron has a charge of -1, so the 2 electrons add a charge of -2.

The net charge of the ion is -2.

Answer:

See explanation and image attached

Explanation:

The reaction of (R)-2-chloro-3-methylbutane with potassium tert-butoxide yields a monosubstituted alkene .

Since the base is bulky, the Hoffman product predominates because attack occurs at the less hindered carbon atom to yield the major product as shown.

The alkene reacts with HBr at the secondary carbon atom to yield a carbocation intermediate which is flat and planar. Attack on either face of the carbocation yields a racemic mixture of the (2R) and (2S) products.

Rearrangement of the carbocation to yield a tertiary carbocation gives the 2-bromo-2-methyl butane product as shown in the image attached.

Explanation:

b. Bromo cyclopentane + HBr

Answer:

I think its A maybe am not sure

Suppose you have a material in it's liquid phase. As you give energy to that liquid, the temperature of the liquid will increase gradually, and the relation between the increase of temperature and the given energy is the specific heat.

Now, there is a point, a critical point, where the temperature stops to increase, which means that we are near a change of phase. So from this point on, the energy is not used to increase the kinetic energy of the particles (which would increase the temperature), the energy is used to break the bonds and allow a change of phase, for example, from liquid to gas.

So, we know that if you have a mol of water at 100°C, then you need to add 40.7 kJ of energy to change the phase of the water from liquid to gas phase.

This means that if you have a mol of water and you give that exact energy, the temperature will not change, instead, you now will have a mol of water at the temperature of 100°C.

Similarly with the case at 25°C (which happens for a particular pressure only)

So the heat of vaporization can not really be related to increases in temperature as you thought.

For changes in temperature, you need to use the specific heat.

We know that for water it is:

c = 4.184 J/g*°C = 76.15 J/mol*°C

So, if you want to increase the temperature from 25° to 100°

This means an increase of 75°C of one mol of water.

We just need to multiply the above number by:

1mol*(75°C)

Energy needed = (76.15 J/mol*°C)*1mol*(75°C) = 5,711.25 J

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Answer:

C

Explanation:

If he can't read his computer screen. Means his eyes have problem

A new member of your team is visually impaired. He's having a hard time reading his computer screen.  value diversity require computer usage. 12 Tell him that he might want to schedule an eye exam. Therefore, option C is correct.

Institutions and community members who value diversity do so in order to recognize the advantages of both their differences and commonalities. They make a deliberate effort to forge enduring connections between individuals and organizations with a broad membership.

When people's unique qualities, abilities, interests, and viewpoints are recognized and supported, they develop a stronger sense of self and health and achieve better results in their academic and professional endeavors.

Although diversity and inclusion are related ideas, they are not the same thing. Diversity has to do with representation or how something is put together. The degree to which the contributions, presence, and viewpoints of other groups of individuals are appreciated and incorporated into a setting is referred to as inclusion.

Thus, option C is correct.

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Answer:

gamma ray

Explanation:

The pressure of hydrogen gas is 607.7 mmHg

According of Dalton's law of Partial pressure, the total pressure of a mixture of gases is the sum of the partial pressures of the individual gases in the mixture.

We can now write;

The for hydrogen collected over water, we have a mixture of hydrogen gas and water vapour.

Total pressure = pressure of hydrogen gas + vapour pressure of water

Pressure of hydrogen gas = Total pressure - vapour pressure of water

Pressure of hydrogen gas =  636 mmHg - 28.3 mmHg

Pressure of hydrogen gas = 607.7 mmHg

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Answer:

12

Explanation:

2+8+2=12

atomic no is the No of protons

Answer:

Atomic number is 12.

Explanation:

Atomic number = electrons in filled shells + outermost electrons

= 2 + 8 +2

= 12

In this figure, four shapes contains the same text as in the red oval. The text given in the red oval is KTKEIHLPEQMKJAPDEK.

Shape is "the form of an object or its outline, outer boundary or outer surface".

Text is "a collection of words or letters that are understandable by the reader".

Oval is a rounded and slightly elongated outline or shape like that of an egg.

Hence, four shapes contains the same text as in the red oval.

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Answer:

catenation

Explanation:

Carbon atoms have four electrons to share in bonding environments to get to the ideal octet. To do this, it bonds with other carbon molecules, called catenation. Catenation is the ability of an atom to bond and share electrons with other atoms of its kind.

Your answer is CaO.I hope that my answer helped you..

The correct order of the substances in order of decreasing boiling point is,

KF , CH30OH , CO2 , Ne

Boiling point, the temperature at which the force exerted by the surroundings upon a liquid exists equaled by the pressure exerted by the vapor of the liquid; under this situation, the addition of heat affects the transformation of the liquid into its vapor without increasing the temperature.

The main difference between the boiling point and the melting point stands that the melting point is determined as the temperature at which solid and liquid phases exist in equilibrium, whereas the boiling point stands as the temperature at which the vapor pressure of a liquid stands equal to the external pressure.

Hence, The correct order of the substances in order of decreasing boiling point is,

KF , CH30OH , CO2 , Ne

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Answer:

Cs> Ba> Pb>Si> P>O

Explanation:

Recall that atomic size decreases across a period and increases down the group.

As we move from Cs to Ba, the atomic size decreases across the period. Lead is larger than silicon since atomic size increases down the group.

Between phosphorus and oxygen, phosphorus is larger than oxygen as you move across the period.

Explanation:

Hey there!

Charles law states that the volume of gas is directly proportional to the absolute temperature at constant pressure.

As the fact is, at a constant pressure the volume of fix amount of dry gas is directly proportional to absolute temperature from Charles law.

Since V and T are directly varying directly, we can write the equation using constant "k".

V/T = k

In this case the value of k depends on the pressure of gas, the amount of gas and also unit volume.

V/T = k .........(i)

Let us consider V1 and T1 the Volume and temperature of the ideal gases.

Then the equation is;

V1/T1 =k........(ii)

After this let change the temperature and volume be T2 and V2, respectively.

Then the equation is:

V2/T2 = k.......(iii)

Now; Equating equation (ii) and (iii)…

V1/T1 = V2/T2

So, this the formula. (i.e V1/T1 = V2/T2).

Hope it helps!

Answer:

Molarity is a measure of concentration

I Hope its right if not so advance sorry :)

The molarity measures the number of moles of the solute present per liter of the solution and it measures the concentration of the solution. option D is correct.

Molarity is the amount or the number of moles present in per liter of the solution it is the unit to measure the concentration of the moles.

Unit of molarity will be moles per liter and the temperature does not affect the molarity of the solution. molarity can be calculated by dividing the concentration of the solution by the molar mass of the given element.

molarity = weight / mass ×  1000/ volume in liters.

With the help of this formula, we can calculate the molarity.

Therefore,  molarity measures the number of moles of the solute present per liter of the solution and it measures the concentration of the solution. option D is correct.

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Answer:

361.4 pm is the length of the edge of the unit cell

Explanation:

First, let's calculate the average volume each atom is taking. Start with calculating how many moles of copper we have in a cubic centimeter by looking up the atomic weight. Atomic weight copper = 63.546 Now divide the mass by the atomic weight, getting 8.94 g / 63.546 g/mol = 0.140685488 mol And multiply by Avogadro's number to get the number of atoms: 0.140685488 * 6.022140857x10^23 = 8.472278233x10^22 Now examine the face-centered cubic unit cell to see how many atoms worth of space it consumes. There is 1 atom at each of the 8 corners and each of those atoms is shared between 8 unit cells for for a space consumption of 8/8 = 1 atom. And there are 6 faces, each with an atom in the center, each of which is shared between 2 unit cells for a space consumption of 6/2 = 3 atoms. So each unit cell consumes as much space as 4 atoms. Let's divide the number of atoms in that cubic centimeter by 4 to determine the number of unit cells in that volume. 8.472278233x10^22 / 4 = 2.118069558x10^22 Now calculate the volume each unit cell occupies. 1 cm^3 / 2.118069558x10^22 = 4.721280262x10^-23 cm^3 Let's get the cube root to get the length of an edge. (4.721280262x10^-23 cm^3)^(1/3) = 3.61426x10^-08 cm Now let's convert from cm to pm. 3.61426x10^-08 cm / 100 cm/m * 1x10^12 pm/m = 361.4 pm Doing an independent search for the Crystallographic Features of Copper, I see that the Lattice Parameter for copper at at 293 K is 3.6147 x 10^-10 m which is in very close agreement with the calculated amount above. And since metals expand and contract with heat and cold, I assume the slight difference in values is due to the density figure given being determined at a temperature lower than 293 K.

The compound in this reaction which is having the elemental ratio of 1:4:1 is NH₄Cl where nitrogen and chlorine are of one mole each with 4 hydrogens.

Elemental ratio of a compound is the ratio of number of atoms  of each  elements in that compound. The elemental ratio can be determined from the molecular formula of compounds.

The given reaction is a double displacement reaction. Here, the Cl group is replaced to the ammonia and OH group is replaced to the water. Thus, two species is replaced in the reaction.

In NH₄Cl, there are one nitrogen, 4 hydrogens and one chlorine atom. Therefore, the elemental ratio of the compound is 1:4:1. The elemental ratio of water is 2:1 and HCl is 1:1 and that in NH₄OH is 1:5:1. Hence, option b is correct.

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Answer:

Have you ever touched a fish? Most fish will feel a bit rough - due to their scales. Some, like sharks, will feel like sandpaper. Even fish with small, smoother scales will feel a bit like that. Amphibians don’t have scales, and most species will be wet to some degree - they have to keep their skin moist or they’ll die. A few groups, like toads and newts, have rougher skin, which is heavier and thicker, which allows them to retain moisture better away from water.

Functionally, the big thing about amphibian skin is that it is semi-permeable. Amphibians can breathe through their skin - all amphibians can get some oxygen through their skin, but some species of salamanders get all their oxygen that way - they have no lungs or gills. The skin can also allow water in - sort of like a paper towel. The bad thing is that other chemicals can pass through the skin, too - pollutants and other chemicals tend to affect amphibians far more than they do other groups.

Amphibians also shed their skin - fish do not. People don’t tend to see frogs shedding their skin often, though, since they eat it to regain nutrients and other resources in the skin.

Finally, since amphibian skin offers no defense against predators in the way that scales do, and limited barrier against disease the way non-amphibian skin does (shedding helps), the skin of many amphibians contain toxins, and some of them have anti-fungal properties (typically due to symbiotic bacteria). Many species have evolved chemical defenses in the skin, while others have glands that produce toxins that can be secreted outside of the skin.

The skin can withstand dessication more than the fish.

They have moist skin used as respiratory surface during deep sleep / hibernation.

They have moist skin due to secretion of mucus by glands under the skin.

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Answer:

duw8 Wert gsi

Explanation:

pues pues y 8y1rcuecisscfjfj3eoeu xv cihskdkkd HD jekifeuifkeñ elijo eh fh FC eh SSH DJ djdvheshdhs

The mass percent of antimony in the sulfide is 71.7% and the mass of Sb2S3 is 0.148 g.

Mass percent is defined as a way of expressing a concentration or describing a component in a particular mixture.

To calculate the mass percent of an element in a compound, divide the mass of the element in 1 mole of the compound by the molar mass of the compound and multiply the result by 100.

Mass percent = Mass of chemical / Total mass  of compound x 100

Mass of ore = 10 kg

% antimony in ore = 10.6%

                              = 10.6 / 100 = 0.106 g

Mass of antimony = 0.106 g

Mass percent = Mass of antimony / Mass of stibnite x 100

71.7% = 0.106 / X x 100

X = 0.106 x 1000 / 71.7 x 1000

  = 106 / 717 = 0.148 g

Thus, the mass percent of antimony in the sulfide is 71.7% and the mass of Sb2S3 is 0.148 g.

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Answer:

I don't know What can I do.

Answer:

43) protein

44) oxidoreductase