Below is a list of some substances and their symbols.
Oxygen O
Sodium Chloride NaCl
Gold Au
Neon Ne
How many of these substances are an example of an element?

Formal charges represent the actual charges on atoms in a molecule.

The formal charge can be used to determine the most plausible Lewis structure for a given compound.

A formal charge is defined as the charge that is assigned to an atom in a molecule in which we assume that electrons in all chemical bonds are shared equally between two atoms without relative electronegativity. The formula for assigning formal charge to atoms in the Lewis structures is given below:

Formal charge = Number of valence electrons - (number of lone-pair electrons + half number of bonding electrons).

''Lone pair electrons" are also called "nonbonding pairs" or "unshared pairs".  When an atom has several bonds and a complete octet shell, then its formal charge is 0. Formal Charge is the charge of an atom in a molecule or ion in which all of the bonding electrons were divided between atoms in the bond equally.

So we can conclude that options A and C are the correct answer.

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In addition to acting as a comparison to the post-partition salicylic acid solution, the pre-partition salicylic acid solution (no mixing with chloroform) serves a 2nd propose to act as a standard for linear regression analysis.

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The approximate pressure of 2 moles of helium in a 0.3m³ container at 300 K is 17000 Pa (option B).

The pressure of a gas can be calculated using the following formula;

PV = nRT

Where;

According to this question, 2 moles of helium in a 0.3m³ container is at 300K. The pressure can be calculated as follows:

P × 300 = 2 × 0.0821 × 300

300P = 49.26

P = 0.164 atm

This pressure value in Pascals is 16617.3, which is approximately 17000 Pascals.

Therefore, the pressure of a 2 moles of gas is 17,000 Pascals.

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Because a flux-pressure curve is initially measured before the pore size distribution is determined, the liquid displacement method is an indirect approach for determining the pore size distribution of a membrane.

Water displacement method - To do this, all you need to do is place the food in a resealable zipper-lock bag, and then carefully lower the bagged food into the cooking vessel filled with water. Air is forced through the top of the bag by the water's pressure. Carefully seal the bag once the majority of the air has been removed, just above the water line.

Total volume minus liquid volume equals volume of the thing.

6.2 mL minus 5.5 mL equals 0.7 mL.

Now, the object's density will be;

Mass / volume equals density (Liquid - Displacement).

We swap out

Density = 0.66 g / 0.7 mL (Liquid - Displacement)

Density = 0.942857 0.94 g/mL (Liquid - Displacement).

As a result, the cube's density for the liquid displacement method is 0.94 g/mL.

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The energy of a 4.25 × 10⁸ Hz wave is 2.816 × 10-²⁵ J.

The energy of a wave can be calculated by multiplying the frequency of the wave by Planck's constant as follows:

E = hf

Where;

According to this question, the frequency of a wave is given as 4.25 × 10⁸ Hz. The energy, if the Planck's constant is 6.626 × 10-³⁴ J/s, can be calculated as follows:

E = 6.626 × 10-³⁴ × 4.25 × 10⁸ Hz

E = 2.816 × 10-²⁵ J

Therefore, the energy of the wave is 2.816 × 10-²⁵ J.

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36.78% (percent) of NaCl is present in the original sample mixture of NaCl and [tex]BaCl_2.2H_2O[/tex].

Given:

Original mass of sample mixture containing NaCl and [tex]BaCl_2.2H_2O[/tex] = 5.416g

After heating, the mass of the sample = 4.911g

To find:

Percent of NaCl in the sample = ?

Formula:

Percent of NaCl in the sample = (Mass of NaCl / Mass of original sample) x 100

Calculations:

Mass of water = 5.416 - 4.911 = 0.505g

Molar mass of [tex]BaCl_2[/tex] = 208.23g/mol

From the chemical formula - [tex]BaCl_2.2H_2O[/tex],

2 mols of [tex]H_2O[/tex] is attached with 1 mole of [tex]BaCl_2[/tex]

Therefore, with 208.23g of [tex]BaCl_2[/tex] , 36.03g of [tex]H_2O[/tex] is attached.

Therefore, 0.505g of [tex]H_2O[/tex] is attached with:

(208.23 / 36.03) x 0.505g of [tex]BaCl_2[/tex].

= 2.919g of [tex]BaCl_2[/tex]

Thus, Mass of NaCl in the original sample mixture = 4.911 - 2.919 = 1.992g

Percent of NaCl in the sample mixture = (1.992 / 5.416) x 100

Percent of NaCl in the sample mixture = 36.78 %

Result:

The percent of NaCl in the original sample mixture is 36.78%

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Whenever you are trying to find the volume of something you have to multiply length by width and by height

Sociology emerged in the early 1800s during a period of great social change when many academics and other educated citizens were fascinated by scientific discoveries social issues like the low high school graduation rate continue to interest sociologists today still important to understand and study society today because it gives students an understanding of the real world around them

Sociology is the of human society and social behavior and it started from 1800s during a period of great social change and studying social sciences gives students an understanding of the real world around them an students learn about places, cultures, and events around the world, what conspired to make them the way they are can make inferences about how the rest of the world works

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1. mercury - metal, liquid at temperature

2. oxygen - does not have a definite volume

3.Bromine - non-metal, liquid at room temperature

4.mercuric oxide - compound

5. silver -malleable and ductile

6. chemical change - decomposition of compound

The only common metal that is liquid at room temperature is mercury, a chemical element. It is a thick, silvery-white liquid metal that is frequently referred to as quicksilver. Mercury is a metal in transition.

Since mercury is a chemical element, it cannot be made or destroyed. Since the creation of the earth, the same quantity has been present on the planet. However, both natural and human activity can cycle mercury in the environment. Additionally, there have been numerous new uses for mercury metal in electrochemistry and electrical equipment. Mercury metal has a significant vapour pressure at normal temperature and is a volatile liquid.

At 20°C, mercury has a density of 13.6 g.cm-3.

Mercury is a metallic element that is liquid and has a wide range of uses. Additionally, it has dangerous qualities.

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The pH of KOH  is 10.14 and the hydronium ion concentration of the solution is   3.9 × [tex]10^{-5}[/tex]  M .

The pH and the hydronium ion concentration of the solution of KOH is calculated as ,

The pOH = - ㏒ [  [tex]OH^{-}[/tex] ]

Given , concentration of hydroxide ion =  1.4 × [tex]10^{-4}[/tex] M

So put the value of  concentration of hydroxide ion in equation 1

pOH = - ㏒ 1.4 × [tex]10^{-4}[/tex] M

pOH = 3.85

pH + pOH = 14

pH  =  = 14 - pOH  =  14 - 3.85 = 10.14

pH = - ㏒ [  [tex]H^{+}[/tex] ] = 10.14

[  [tex]H^{+}[/tex] ]  =   3.9 × [tex]10^{-5}[/tex]  M

Therefore , the pH of  1.4 × [tex]10^{-4}[/tex] M solution of KOH is 10.14 .

Therefore , the  hydronium ion concentration of the solution is   3.9 × [tex]10^{-5}[/tex]  M .

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Looking at the Nernst equation (the equation used to calculate the reduction potential of a half-cell or a cell), we can conclude that the difference between [tex]E_{cell}[/tex] and [tex]E^{0}[/tex] is a function of absolute temperature and the reaction quotient.

The Nernst equation looks like this:
[tex]E = E^{0} -\frac{RT}{zF}lnQ[/tex]

[tex]E[/tex] is the reduction potential of the reaction in question,
[tex]E^{0}[/tex] is the standard electrode potential,
[tex]R[/tex] is the universal gas constant,
[tex]T[/tex] is the absolute temperature (in Kelvins),
[tex]z[/tex] is the number of electrons transferred in the course of the reaction,
[tex]F[/tex] is the Faraday constant, and
[tex]Q[/tex] is the reaction quotient calculated as the ratio of products and reactants

From this, we can see that the variables for the difference between [tex]E_{cell}[/tex] and [tex]E^{0}[/tex] for a given reaction are absolute temperature and reaction quotient, because [tex]R[/tex], [tex]F[/tex] and [tex]z[/tex] remain constant.

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" It is a synthetic substance made with natural materials."

Plastics are high molecular mass organic polymers that frequently incorporate additional materials.

Typically, they are synthetic and come from petrochemicals.

Plastics are produced from natural resources including coal, natural gas, salt, and crude oil through the polymerization process.

The process of joining monomer molecules in a chemical reaction to create polymer chains or three-dimensional networks is known as polymerization, in the field of polymer chemistry.

These monomers combine to create a lengthy chain that gives rise to a final product with particular features. Polymerization refers to the entire process of a polymer being created. Polymers include things like polythene and nylon 66.

Thus, we can define plastics as synthetic materials produced from natural resources.

Plastics are therefore a synthetic material made from natural materials.

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30° Celsius is equivalent to 303° Kelvin (option A).

Temperature is a measure of cold or heat, often measurable with a thermometer.

Temperature can be measured in Kelvins, according to the standard international systems of units. Although it has other units of measurement such as;

The conversion factor of degrees Celsius to Kelvin is as follows:

K = °C + 273

According to this question, 30° Celsius is given. This measurement in Kelvins can be calculated as follows:

K = 30°C + 273

K = 303K

Therefore, 303K is the equivalent measurement of 30°C.

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Answer: L

Explanation:

The way that continental crust different from oceanic crust is that option B: Oceanic crust is thinner and younger.

Oceanic crust is much, much younger than continental crust, mostly as a result of subduction. The Ionian Sea, which is a component of the eastern Mediterranean basin, contains or has the oldest known oceanic crust.

Therefore, Oceanic crust differs from continental crust in a number of respects, including thickness, as well as density, age, and also that of chemical make-up. However, in subduction zones, oceanic crust is likewise destroyed.

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Avogadro's number (6.02*1023) of something is defined as 1 mole. So one mole of sulfur (or any other element) equals 6.02*1023 atoms. 4.56 moles is only 4.56 times as much.

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The mass of the heat and tempreture will be "12.33 g".

what is heat and tempreture?

The energy is transmitted from one object to the next as a consequence of something like a temperature differential.

The heat has been affected by elements such as particle speed, physical properties, as well as particle quantity, among others.

As per the question

Heat, ΔH = 81.0 J

Specific heat, C = 0.450 J/g°C

Temperature, ΔT = 32.5 - 17.9

        = 14.6°C

Enthalpy change of a process -

→ ΔH = m × C × ΔT

By substituting the values, we are getting

81.0 = m × 0.450 × 14.6

    m = 12.33 g

So  this answer is correct.

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Answer:

absorption of light and Carbon Fixation

Explanation:

If you look at the molar mass of sodium on the periodic table, it is 22.99 grams/mole. If you look at the molar mass of chlorine on the periodic table, it is 35.45 grams/mole.

To find the molar mass of sodium chloride, we add these two values and that gets us 58.44 grams/mole.

Alright, so we know that 1 mole of NaCl is equal to 58.44 grams, so how many moles would 23.5 grams of NaCl be?

Now we just divide 23.5/58.44 and you get 0.40 moles of NaCl. (If you're confused on what value to put in the numerator, always put the value that you're interested in converting or calculating for.)

Answer: 0.40 moles

Given the fact that we are seeing a rise in the temperature of the globe, the artic animals in that ecosystem must adapt by a reduction in the rate of metabolism.

Several evidences continue to emerge that the temperature of the earth have continued to increase and this is largely due to the fact that since the turn of the twentieth century and the rise of industrialization, there have been a rise in the emission of the carbon dioxide and other green house gases into the environment. As a result of this, the temperature of the earth has continued to rise steadily leading to the melting of the ice cover and the destruction of ecosystems that are found around the artic regions of the earth.

Now, we know that an organism is able to adapt to the changes that occur in its habitat by being able to alter some of its structure and function.

Given that the organisms that live in the artic are adapted to cold regions and low temperatures, the metabolic rate of the organisms is high in order to produce heat.

As a result of the rise in global temperatures, the organisms would have to reduce their rate of metabolism.

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Explanation:

from

c1v1=c2v2

c1=?

c2=0.250

v1=0.0225

V2=0.0100

c1×0.0225=0.250×0.0100

0.0225c1=0.0025

0.0225c1/0.0225=0.0025/0.225

c1=0.1111

Answer:

The electron structures of the group 14 (4A) elements are similar in that they are all part of the carbon group. Thus, they each have 4 electrons in their valence shell. Also, most of these elements are found in our daily lives except germanium. They are different in that their properties differ greatly despite them being somewhat alike.

Explanation:

I hope this helps! I took this class last year.

If the actual volume of the block was 145.3, then their percent error was −10.18%

The difference between an observed value and a true, accepted value is measured as percentage error. The outcome of data measurement frequently deviates from the actual value.

Error can occur for a variety of reasons, often related to human error, but also due to estimations and the limitations of the measurement tools used.

In any case, figuring out the percentage error in these situations can be helpful. The absolute error, or difference between the observed and true value, is used to calculate percentage error.

The relative error is then multiplied by 100 to produce the percentage error after the absolute error is divided by the true value.

Volume of a cube = s³

Volume of the cube is then

V = 5.08 × 5.09 × 5.1

V = 131.87 cm³

Percent errors are calculated by the following formula

%E = (V.a - V.e)/V.a × 100%,

where

%E = percentage error

V.a = actual volume

V.e = expected volume

Substituting the values we get

%E = (131.87 - 145.3) / 131.87 × 100%

%E = −13.43 / 131.87 × 100%

%E = −0.1018 × 100%

%E = −10.18%

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The law that explains the given observation of the formation of carbon monoxide and carbon dioxide is the law of multiple proportions.

The correct answer choice is option C.

The law of multiple proportions states that when an element combines with another element B to form more than one compound, the mass in which the different masses of A combine with a fixed mass of B are in simple multiple multiple ratios.

The law of multiple proportions can be explained below using C and O:

C combines with O to form carbon monoxide and carbon dioxide respectively.

Carbon monoxide can be formed by reacting 12 grams of carbon with 16 grams of oxygen.

However, to form carbon dioxide, 12 grams of carbon must react with 32 grams of oxygen.

Ratio of O in carbon monoxide and carbon dioxide = 16 : 32

Ratio of O in carbon monoxide and carbon dioxide = 1 : 2

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The answer is the first one.

Answer:

3.1 * 10^-19 joules

Explanation:

The equation you want to use is:
E=hc/lambda (lambda = wavelength).
It might also be given to you in the form:
E=constant/wavelength

since h = 6.626*10^-34, c = 2.998*10^8,  and the wavelength is 6.4*10^7, the values can be plugged into the equation to solve for the energy.

E=(6.626*10^-34 * 2.998*10^8) / (6.4*10^-7) = 3.1 * 10^-19 joules

The concentration of the barium chloride solution is found to be 29.67 µmol/L.

The quantity of solute that has been dissolved in a certain volume of solvent or solution is measured by the solution's concentration. A solution that contains a lot of dissolved solute is said to be concentrated. If there is just a little amount of dissolved solute in a solution, it is said to be dilute.

Molarity is one of the most often used ways to represent the concentrations of solutions. It is the quantity of moles of solute dissolved in a solution that is one liter in size.

Given:

Barium chloride = 8.9 µmol

Volume = 300ml

To find:

Concentration of the solution = ?

Formula:

(Concentration of solute / volume of solution) x (1000mL/1L)

Calculations:

(8.9 / 300) x (1000/1)

= 29. 67 µmol/L

Result:

Therefore, the concentration of the barium chloride solution is 29.67 µmol/L

The complete question is:

A chemist prepares a solution of barium chloride by measuring out 8.9 μmol of barium chloride into a 300mL volumetric flask and filling the flask to the mark with water.

Calculate the concentration in μmol/L of the chemist's barium chloride solution. Round your answer to 2 significant digits.

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The student added sodium chloride in order to precipitate lead II chloride because this is a positive test for lead II ions.

Some times when we carry out an aqueous phase reaction, the products of the reaction would be found to be in the solid phase. This implies that one of the products of the reaction is insoluble in water and separates out of the solution.

In this case, the student knows that lead II chloride is insoluble in water thus it is obtained upon the addition of sodium chloride. This informed the addition of the sodium chloride solution.

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Missing parts;

A 50.0 mL unknown aqueous sample was tested in the laboratory. The unknown sample was identified

to be lead (II) ions by a precipitation reaction with sodium iodide. Since the unknown was identified to

have lead (II) ions in it, a student added excess sodium chloride (NaCl) to the 50.0 mL sample. A white

precipitate was made and was subsequently filtered, washed, and dried to completion. The precipitate

was measure to have a mass of 2.350 grams.

(a) How did the students determine through the addition of sodium iodide that the sample had lead (II)

ions in it?