phosphorus pentachloride, pcl5, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. calculate the number of moles in 55.7 g of pcl5

Atomic number. should be 120.

due to.... a/q

Alkaline earth metals are part of the eighth group and are known to exist in two groups.

Consequently, the element's atomic number will be 120.

The quantity of protons in an atom's nucleus is known as the atomic number. An element's identity is determined by its proton count (i.e., an element with 6 protons is a carbon atom, no matter how many neutrons may be present).

A chemical element's atomic number is its position in the periodic system, which places the elements in ascending order of the number of protons in their nuclei. As a result, the atomic number is also determined by the number of protons, which is always equal to the number of electrons in a neutral atom.

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The true statement about the reaction is that the reaction reaches equilibrium around 1.5 seconds.

We say that a reaction is reversible if the reaction can proceed both in the forward and the reverse directions. Let us recall that it is possible for a reversible reaction to attain a status of dynamic equilibrium. The status of dynamic equilibrium is the status where the rate of the forward reaction is equal to the rate of reverse reaction.

If we look at the graph as we have it we would notice that there is such a point of dynamic equilibrium as we survey the system around 1.5 seconds.

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The true statement about the reaction is the reaction reaches equilibrium around 1.5 seconds. Thus option D is correct.

Reversible reaction is defined as a reaction in which the transformation of both reactants and products into one another takes place simultaneously.

If a response may occur in both the forward and reverse directions, we say that it is reversible. Let's not forget that a reversible reaction can reach a state of dynamic equilibrium. The condition known as dynamic equilibrium occurs when the forward reaction rate and the backward reaction rate are equal.

If we were to examine the graph as it currently stands, we would see that the system reaches a point of dynamic equilibrium after 1.5 seconds of observation.

Thus, the true statement about the reaction is the reaction reaches equilibrium around 1.5 seconds. Thus option D is correct.

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The atomic mass of silicon is calculated to be 28.1087 amu if the three isotopes have relative abundances of 92.23%, 4.67%, and 3.1%, respectively.

The atomic mass of an element can be determined by first changing the percentage abundance of each isotope into decimal form, then multiplying this value by the atomic mass of that isotope. Then the resultant value of each isotope is added together to get the atomic mass of the element.

As the mass of the three isotopes of silicon is 28 amu, 29 amu, and 30 amu  with relative abundances of 92.23%, 4.67%, and 3.1%, respectively, we can calculate the atomic mass of silicon as follows;

si-28 = 92.23% = 92.23/100 = 0.9223

si-29 = 4.67% = 4.67/100 = 0.0467

si-30 = 3.1% = 3.1/100 = 0.031

Now multiplying these values by the atomic mass;

si-28 = 0.9223 × 28 = 25.8244

si-29 = 0.0467 × 29 = 1.3543

si-30 = 0.031 × 30 = 0.93

Now adding these values together;

atomic mass of silicon = 25.8244 + 1.3543 + 0.93

atomic mass of silicon = 28.1087 amu

Therefore; the atomic mass of silicon is calculated to be 28.1087 amu.

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Photochemical smog effects largely the growth of plants by interfering in nitrogen cycle and by causing atmospheric pollution.Thus option D is correct.

Photochemical smog is a brown haze in the atmosphere formed by the burning of fuels and from naturally released pollutants when exposed to UV radiation undergo  a series of hydrocarbon reactions to produce photochemical smog.

The main composition of photochemical smog is oxides of nitrogen and it further undergo further reaction with hydrocarbons entered into he atmosphere by burning fuels produce secondary pollutants.

These secondary pollutants again creates air pollution and serious other issues such as reduction in plant growth because they interfere the atmospheric nitrogen cycle which is essential for crop yield.

Hence, photochemical smog can decrease the crop yield in a region and option D is correct.

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The weighted average of the nail size in the sample data is 0.0571 d.

To calculate the weighted average of the nail sizes in the given data, we need to first calculate the total mass of all the nails in the sample. We can do this by multiplying the number of nails of each size by the mass of one nail of that size and then adding up the results:

Total mass = (24 nails of size 3d) x (3.30 g/nail) + (176 nails of size 16d) x (12.25 g/nail)

Total mass = 79.20 g + 2156.00 g

Total mass = 2235.20 g

Next, we can calculate the weight fraction of each nail size by dividing the mass of nails of each size by the total mass:

Weight fraction of 3d nails = (24 nails) x (3.30 g/nail) / 2235.20 g = 0.000360

Weight fraction of 16d nails = (176 nails) x (12.25 g/nail) / 2235.20 g = 0.007901

Finally, we can calculate the weighted average of the nail sizes by multiplying each weight fraction by the corresponding nail size and then adding up the results:

Weighted average = (0.000360 x 3d) + (0.007901 x 16d) = 0.0571 d

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The balloon and the comb definitely have the same electrical charge. Option 2.

According to the law of attraction in physics, like charges repel while unlike charges attract.

Going by this law:

In other words, if 2 objects that have the same charges are brought close to each other, there will be a repulsion. If the 2 objects are of different charges, there will be an attractive force between them.

The students observed that the comb repelled the balloon. The implication is that the comb and the balloon are of the same charge.

This is logical considering the fact that both objects were rubbed against hair. They got their charges during the process of rubbing. An electrostatic force is generated that moves electrons from the hair to the two objects.

Thus, both the balloon and the comb are negatively charged and will, therefore, repel each other.

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An example of positive feedback in the human body may be the increased production of a hormone in response to the products of the same hormone, a stimulus is a reaction produced as a consequence of a change in the environment, while a response impacts the stimulus to maintain homeostasis.

The expression positive feedback is used in biology to explain the output of a process that may feed the input of the same biological process, such as occurs when a hormone is synthesized depending on the concentration of its hormonal product.

Moreover, a stimulus is a change in conditions that surround an organism and it leads to a concomitant response to maintain the state of equilibrium which is referred to as homeostasis.

Therefore, with this data, we can see that homeostasis and stimulus are interrelated, which positive feedback is a response as the output of the same process.

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Answer:

d

Explanation:

the group's name is called noble gases. hence they are all gases.

The chromatography experiment which would best decide whether the compounds are identical or not is to Repeat the original experiment once more with various solvent systems;

If two things have the same Rf value, they are probably the same compound, but not always. They are definitely distinct compounds if their Rf values differ.

Compounds with a low polarity have higher Rf values than compounds with higher polarity. Compounds' absorptivity typically rises in tandem with their polarity—that is, the more polar a compound is, the more strongly it binds to the adsorbent. Solvents' eluting power increases with polarity. In diverse solvents, different compounds with identical Rf values might behave differently.

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Answer:

The easiest way to find the number of neutrons, protons, or electrons is to look at the element's atomic number on the periodic table, that number is equal to the number of protons. Which is equal to the number of electrons unless there's an ion superscript listed after the element.

Explanation:

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The conjugate base of a compound is what this compound will be after donating a H⁺.

The comopund in question is H₂BO₃⁻. After it loses 1 H⁺, it will have one less H atom and its charge decrease by one. Its charge is only with a "-" sign, which means its chargeis 1-. After decreasing by one, the charge becomes 2-.

So, the conjugate base will be HBO₃²⁻

A process through which a large molecule such as a protein could leave the cholera cell is generally referred to as: c) exocytosis.

Cholera can be defined as a type of disease which is typically caused by a bacteria that is referred to as Vibrio cholerae. Also, cholera gets into the body of a living organism through an ingestion of contaminated food or water.

Exocytosis simply refers to a process which typically involves a cell releasing a large amount of a material (bulk transport) outside of the cell, especially through the use of vesicles.

This ultimately implies that, exocytosis can be defined as a biological process in which living organisms release (expel) large amount of unwanted material by using the vesicles.

Additionally, exocytosis is a biological process that is initiated by the Golgi apparatus and it can be used to expel a large molecule such as protein from cholera cells.

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Complete Question:

In the first stage of cholera, the bacterium finds a host cell in the small intestine. The bacterium then releases toxic proteins called toxins near the host cell. Through which process could a large molecule such as a protein leave the cholera cell?

a) osmosis

b) diffusion

c) exocytosis

d) endocytosis

First acid solution contains 19 liters of 25% acid, second acid contains  19 liters of 45% acid, and the third contains 57 liters of 45% acid.

Let us take x as the liters of 25% acid, y as the liters of 45% acid, and z as the liters of 85% acid.

From this we get an equation:

x + y + z = 95    

0.25x + 0.45y + 0.85z = (0.65)95

By equating both the equation we have:

y + 3z = 190

y = 190 - 3z  

It is given that z = 3y

Solve the system of equations using eliminating or substituting we get:

x + y + z = 95

x + y + 3y = 95

x  + 4y = 95

x = 95- 4y

0.25( 95 - 4y ) + 0.45y + 0.85(3y) = (0.65) 95

23.75- y + 0.45y  + 2.55y = 61.75  

2y = 38

y = 19

x = 95 - 4y

  = 95 -76

   = 19

z = 3y

 = 3× 19

 = 57

Therefore the chemist needs 19 liters of 25% acid, 19 liters of 25% acid and, 57 liters of 85% acid.

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Answer:

MnO

Explanation:

See the attachwed worksheet

Answer:

There are 400 meters in a hectometer?

Explanation:

Answer:

there are 400 meters in a hectometer?

Explanation:

Answer:

HS is stripped from each O.

Answer:

it would be the same weight but it's ith sugar I think it would way more

The concentration of the unknown weak acid solution is 0.228 M.

Acid dissociation constant, K a K text a Ka, and weak acids. Acids that don't entirely dissociate in solution are referred to as weak acids. In other words, any acid that is not a strong acid qualifies as a weak acid. The amount of dissociation determines how strong an acid is; the more dissociation, the stronger the acid.

Equivalent point:

Since the volume is 4.00 mL of the weak acid, and it takes  18.3 mL of 0.0500 M NaOH to reach the equivalence point.

We know that

In the equivalence point, [H⁺] = [OH⁻].

here the given formula C₁V₁=C₂V₂ is used

Here

C₁ = 0.0500 M

V₁ = 18.3 mL

C₂ = ?

V₂ = 4.00 mL

So, the C₂ is

0.0500 M * 18.3mL = C₂ * 4.00 mL

C₂ = 0.228M

The concentration of the unknown weak acid solution is 0.228 M

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To make a 100 ml solution of 0.8 m from a 2.7 m concentrated stock solution we have to take a volume of: 30 ml of the concentrated solution

To solve this problem, the formula and the procedure that we have to use is:

c1 * v1 = c2 * v2

Where:

Information about the problem:

Applying the dissolution of concentrations formula and clearing the volume of the concentrated solution (v1) we get:

c1 * v1 = c2 * v2

v1 = (c2 * v2)/ c1

v1 = (0.8 m * 100 ml)/ 2.7 m

v1= 29.6 ml

By rounding the volume to a whole integer value we have:

v1= 30 ml

In chemistry a solution is known as a homogeneous mixture of two or more components called:

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Answer:

use a tumbler to cover a candle that is burning, after a few minutes it turns off automatically without any external forces due to the absence of oxygen

Explanation:

The enzyme that catalyzes the synthesis of ATP as hydrogen ions flow down their concentration gradient is called ATP synthase.

In the inner mitochondriаl membrаne, hydrogen ions hаve just one chаnnel аvаilаble: а membrаne-spаnning protein known аs АTP synthаse. Conceptuаlly, АTP synthаse is а lot like а turbine in а hydroelectric power plаnt. Insteаd of being turned by wаter, it’s turned by the flow of hydrogen ions moving down their electrochemicаl grаdient. Аs АTP synthаse turns, it cаtаlyzes the аddition of а phosphаte to АDP, cаpturing energy from the proton grаdient аs АTP.

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Metallic solids,

the atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties. All exhibit high thermal and electrical conductivity, metallic luster, and malleability.

Answer: c. metallic

The reactant will be potassium iodide and lead (ii) nitrate. The products will be lead (ii) iodide and potassium nitrate.

In the field of chemistry, reactants can be described as starting materials that react together in order to form a product. The reactants are the starting material whereas the products are the ending material.

In the case above, potassium iodide and lead (ii) nitrate are the reacting materials as they are the starting materials. On the other hand, lead (ii) iodide and potassium nitrate are the ending products of this reaction.

While writing a chemical equation, the reactants are written on the left-hand side, before an arrow. On the other hand, the products are written on the right-hand side after the arrow.

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Based on the Principle of Complementary Colors , the  colors and wavelengths expected to be the most strongly absorbed by cu 2+ ions are :-

Orange  : 600–640 nm

Blue       : 450–480 nm

Violet      :400–450 nm  

Green     : 450–560 nm

Red         : 640–700 nm

Yellow      : 560–600 nm

Complementary color are pairs of colors which, while blended or mixed, cancel every different out (lose hue) via generating a grayscale color like white or black. whilst located next to every other, they devise the most powerful contrast for those  colours. Complementary colours may also be known as "opposite colorings".

The RGB coloration version, invented inside the 19th century and absolutely advanced inside the twentieth century, uses combos of pink, inexperienced, and blue mild towards a black heritage to make the colours visible on a computer monitor or television display. Within the RGB version, the primary colors are purple, green, and blue. The complementary number one–secondary combinations are crimson–cyan, inexperienced–magenta, and blue–yellow. Inside the RGB colour version, the mild of  complementary shades, consisting of pink and cyan, combined at full depth, will make white mild, for the reason that  complementary hues comprise mild with the whole variety of the spectrum. If the light isn't always completely severe, the resulting mild will be gray.

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What's phase diagram?

The phase diagram is a pressure vs temperature sketch. On the graph, the different physical states of any system at variable temperature and pressure are shown.

What's a Triple point?

A triple point is the point on a phase diagram where all three states of a system (solid, liquid, and gas) are in equilibrium.

What's a Critical point?

A critical point is that point on the phase diagram where the boundary between the liquid phase and gaseous phase vanishes away.

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When monosaccharides are bonded together c) all of these are correct.

Monosaccharides can be described as sugars from which all other complex forms of sugars are formed. Monosaccharides are the simplest form of sugars the combination of which leads to the formation of disaccharides, polysaccharides and oligosaccharides.

When the monosaccharides join in order to form complex sugar molecules, a single molecule of water is lost by each new link or joining of molecules that occur.

As monosaccharides are simplest of sugars, they are more easily absorbed as compared to other types of sugars.

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The partial pressure of oxygen in such conditions is equal to 160 mm Hg.

As the percentage of oxygen in the air is 21 percent, the mole fraction of oxygen in the air can be calculated as follows;

mole fraction of oxygen in air = 21 ÷ 100 = 0.21

Now we can determine the partial pressure of oxygen by using the equation given by Raoult's law as follows;

partial pressure of oxygen = total pressure of air × mole fraction of oxygen

As the atmospheric pressure at sea level is stated to be 760 mm hg and the calculated value of the mole fraction of oxygen is 0.21, substituting these values in the equation as follows;

partial pressure of oxygen = 760 mm hg × 0.21

partial pressure of oxygen = 160 mm hg

Therefore, the partial pressure of oxygen is calculated to be 160 mm hg.

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In carrying out the first standardization in this experiment, a student used 0.5793 g of potassium hydrogen phthalate (khp) and 24.55 ml of a NaOH solution are needed to reach the equivalence point then the concentration of student NaOH solution is 0.02455 L

Standardization is the process in which determining the exact concentration of molarity of the solution and here given data is

Mass of potassium hydrogen phthalate (C₈H₅KO₄) = 0.5793 g

Molar mass of potassium hydrogen phthalate (C₈H₅KO₄) = 204.22g/mol

The number of mole of potassium hydrogen phthalate present then,

Number of moles = mass/molar mass

Number of moles = 0.5793 g/204.22g/mol = 0.002836 mole

Volume of NaOH present = 24.55 ml

1 ml =  0.001 L then, 24.55 ml = 24.55 ml×0.001 L = 0.02455 L

The concentration (in mol/l) of the student's naoh solution is 0.02455 L

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