Find the element that is oxidized and the one that is reduced Si + 2 F2 --> SiF4

Density relates the mass of a compound to its volume. We will first find the mass of the solution using the density and volume given. We have the following equation:

We clear the mass,

So, the mass of paint is 13950 g. Now the mass percentage of the lead in the paint will be calculated as follows:

The mass percentage of lead in the paint is 0.24%.

ppm concentration means the quantity of solute in milligrams (mg) is in a liter (L) of a solution. So, to calculate ppm concentration we will divide the milligrams of lead (II) nitride between the liters of paint:

The ppm of lead in the paint is 11033ppm.

Answer

Explanation

Given:

[KOH] = 0.01 M

What to find:

The hydroxyl concentration, [OH⁻¹].

Step-by-step solution:

pH or pOH is the measure of acidity or alkalinity of a solution.

Acids have pH ranging from 1 to 6.9 and bases have pH ranging from 7.1 to 14. Neutral substances have a pH of 7.

The dissociation of KOH in aqueous medium is:T

The pH of a 0.670 M solution of Ca(NO₂)₂ is 1.76

When HNO₂ dissociates, it forms H⁺ and NO₂⁻ ions.

HNO₂ ==> H⁺ + NO₂⁻

Ka of HNO₂ = [H⁺] [NO₂⁻] / [HNO₂] = 4.5× 10⁻⁴

Let’s take x for unknown

4.5 x 10⁻⁴ = (x)(x) / 0.670

4.5 x 10⁻⁴ = x² / 0.670

x² = 3.015 x 10⁻⁴

x = 1.74 x 10⁻²

[H⁺] = 1.74 x 10⁻² M

pH is the measurement of the acidity or basicity of a compound. It ranges from  0 to 14

Therefore, the pH of a 0.670 M solution of Ca(NO₂)₂ is

pH = -log [H⁺]

pH = -log 1.74 x 10⁻²

pH = 1.76

The pH of a 0.670 M solution of Ca(NO₂)₂ is 1.76 which lies in the acidic range (0 to 7)

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Explanation:

Aluminum will react with chlorine gas according to the following reaction:

2 Al (s) + 3 Cl₂ (g) ----> 2 AlCl₃

We have to find the mass of Cl₂ that will completely react with 13.5 g of Al. First we have to convert the mass of Al to moles using its molar mass.

molar mass of Al = 26.98 g/mol

moles of Al = 13.5 g * 1 mol/(26.98 g)

moles of Al = 0.500 mol

2 Al (s) + 3 Cl₂ (g) ----> 2 AlCl₃

Now, according to the coefficients of the reaction, 2 moles of Al will react with 3 moles of Cl₂. So the molar ratio between them is 2 to 3. We can use that relationship to find the number of Cl₂ that will react with 0.500 mol of Al.

2 mol of Al : 3 moles of Cl₂ molar ratio

moles of Cl₂ = 0.500 mol of Al * 3 moles of Cl₂/(2 moles of Al)

moles of Cl₂ = 0.750 mol

And finally we can convert back to grams using the molar mass of Cl₂.

molar mass of Cl₂ = 70.91 g/mol

mass of Cl₂ = 0.750 moles * 70.91 g/(1 mol)

mass of Cl₂ = 53.2 g

Answer: a. 53.2 g of Cl₂ for complete reaction.

Was a bit lengthy but I guess you do it like this?

Thermal energy in a circuit comes from the electrical energy that is transformed into heat. It is observed in resistors, capacitances and inductances.

The electrical energy in a circuit is converted into heat by the thermal energy. It relies on the sort of circuit under evaluation, which in turn depends on the circuit's components. These elements include resistors, capacitances, and inductances—individually or in combination.

The sum of the squares of the current, resistance, and power dissipated. The impedance of the circuit must be computed for an LCR circuit. then utilizing the impedance, the circuit's current may be estimated.

P=V^2/R

Hence, the thermal energy in a circuit is observed in resistors, capacitances and inductances.

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answer and explanation

a bronsted-lowry basic is a H+ donor

The easiest way to tell which layer is wich, while performing the extraction experiment is to run a little test.

The test will consist on mixing a sample of both layers in different recipients with water.

After mixing them, the recipient with a homogeneous phase will have the aqueous layer, and the other one will be the organic layer.

Answer: The layer on top.

Explanation:

Assuming you were completing an extraction experiment and had a setup similar to the one below then the organic layer will float on top of the aqueous since most non-halogenated organic solvents have a density of less than 1.

The existence of isotopy shows that the atoms of the same element are not exactly alike.

Recall that the atom is the simplest particle of a substances that is able to take part in a chemical reaction. Note that the empirical study of the atom became much more common after the study of John Dalton that led to the Dalton Atomic Theory.

Now, one of the postulates of the theory is the atoms of the same elements are exactly alike in all respects and are different from the atoms of other elements. The existence of isotopy have shown that the atoms of the same element could be different and behave slightly differently from each other.

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• The bond that exist between the CCl4 compound ,forms a covalent bond ,, this can be illustrated in the diagram below:

• We can see that it contains four non-polar covalent bond between carbon and chloride

Given the hypothetical thermochemical equation, expressed as:

We are to find the enthalpy change (ΔH ) for the reaction 2C → 3 A + B.

• You can see that the, given reaction, 2C → 3 A + B is the, reverse ,of the thermochemical equation 3 A + B → 2 C.

• Since the ,reverse reaction is possible,, the reaction enthalpy has the ,same numerical value, but with the, ,opposite sign

Therefore, the enthalpy change ∆H, in kJ/mol, be for the reaction 2 C → 3 A + B is -65.5kJ/mol

Explanation:

An electrolyte has to be capable of of ionizing and CH40 is not.

Therefore, CH40 is not an electrolyte.

Answer:

False

Let's analyze each option to find what best fit as an answer:

A - the function of a catalyst is to lower the energy of activation in a reaction, causing it to occur in a faster way. Since this question is not much about energy or kinetics, this would be the best fit, adding a catalyst or not adding it would not be too influential in the shift of the reaction.

B - Increasing the pressure in a reaction containing gases will mostly favor the side with a lower value of moles, smaller amount of moles = less pressure, so if we add more pressure, the reaction will shift towards the side of the products

C - If we treat heat as a reactant, if we add more temperature, it will shift towards the products, to counteract this increase of temperature

D - Adding reactants will favor the reaction to shift towards the products

Therefore the answer is letter A

According to the explanation given in the previous session, now we have hexane in an organic compound with the solubility of 0.520 g/mL at 25°C. We need to find the value of volume at 120.0 mg

1 gram = 1000 mg

120.0 mg = 0.12 grams

Now we can calculate the volume:

0.520g = 1 mL

0.12g = x mL

0.520x = 0.12

x = 0.12/0.520

x = 0.231 mL is the volume for this compound

Answer:

Explanation:

Here, we want to get the number of moles in the given mass

Mathematically:

The molar mass of CaCO3 is 100 g/mol

The number of moles is thus:

answer and explanation

we are given initial values of temperature, pressure and volume as well as the final value of temperature and pressure and we are asked to find the final volume.

we can do this using the combined gas equation

P1V1/T1 = P2V2/T2

when we plug in the values we get:

(6atm x78L)/53K = (85atm x V2/17K

8.83 = 85atm x V2 / 17K

V2 = 1.77 Liters

Final temperature of the two pieces of metal is 32.25°C

Temprature is the degree of hotness or coldness of the object

Here given data is

Mass of iron = 150 g

Mass of copper = 275 g

Specific heat of iron = 25.09 J/mol°C

Specific heat of copper = 25.46J/mol°C

Temprature in iron = 47°C = initial temprature = T₁

Temprature in copper = 20°C = initial temprature = T₁'

So here we have to find final temprature of  two pieces of metal =?

So, the formula is Q =mcΔT

Q =  (150 g - 275 g) × (25.09 J/mol°C - 25.46J/mol°C) × ( 47°C-20°C )

Q = 125×0.37×27

Q = 243 J

243 J/125×0.37 = 5.25°C = change in temprature

Initial temprature  = 27°C

Final temprature = ?

ΔT = T₂ - T₁

27°C = T₂ - 5.25°C

T₂ = 27°C +  5.25°C

T₂ = 32.25°C

Final temperature of the two pieces of metal is  32.25°C

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The correct answerwer is option D.

D)The artificial cell will become more turgid.

What is a cell?

The cell is the basic building block of all living things. The human body contains many cells and they provide structure for the body. They take in nutrients from the food and convert them to energy for the body. they also carry out specialized functions.

Artificial cells are engineered particles that look like natural biological cells. example proteins, genes, enzymes, etc

Flaccid cells are shrunken cells while turgid cells are stretched due to the absorption of water.

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In simple terms a covalent bond is when we have sharing of electrons, which means there is no polarity being formed when the elements are bonded, this is more likely to occur with atoms with high electronegativity, or same pair of elements, like O2, where we have O - O (Oxygen bonded with Oxygen), since they have the same electronegativity, there is no charge being formed

The same can not be told for ionic bonds, where we have very different elements being bonded together, with a big electronegativity difference, which means we have polarity being formed (which basically means that we have charge in the compound)

One way to find out if a compound is covalent or ionic is by checking their positions in the periodic table, for example, let's analyze our question

We have:

A) Fluorine - Fluorine, here we have a classical example of covalent bond, since there is no "stronger" element, pulling the electrons towards its side, they are the same, hence, the same strength

B) Carbon - Chlorine, we have two non-metals, with a relatively high electronegativity each one of them, so there is ions being formed, therefore it is covalent

C) Potassium - Oxygen, in this case we have a metal and non-metal bonding together, and since potassium has only 1 electron in its valence shell, it will easily give up this electron to another element, therefore K will receive a positive charge (which means loss of electron) and oxygen will receive a negative charge (which means gain of electron), and this is an ionic bond

D) Oxygen - nitrogen is the same case as letter B

It is also possible to check an electronegativity table, in which there are some rules that helps you understand if a compound is more likely to be covalent or ionic

We have to find the molarity of a solution of Magnesium Fluoride. The definition of molarity is:

Molarity = moles of solute/Volume of solution in L

Our solute is MgF₂:

Molarity = moles of MgF₂ / L of solution

From the problem we know that the volume of the solution that the chemist prepared is 250. mL, we will have to convert that into L.

We know that there are 1000 mL in 1 L. So:

1 L = 1000 mL

250. mL = 250. mL * 1 L/1000 mL = 0.250 L

Volume of solution in L = 0.250 L

Now we have to find the number of moles of MgF₂ that the chemist added. From the problem we know the mass of MgF₂ added. Let's convert it to g:

1000 mg = 1 g

mass of MgF₂ = 6-73 mg

6.73 mg = 6.73 mg * 1 g/1000 mg = 0.00673 g

mass of MgF₂ = 0.00673 g

When we want to find the number of moles that we ave in a certain amount of a compound, we have to use the molar mass. Let's find the molar mass of MgF₂.

According to the periodic table the atomic mass of Mg is 24.3 amu and the atomic mass of F is 19 amu. So the molar mass of MgF₂ is:

molar mass of MgF₂ = 24.3 + 2 * 19 = 62.3 g/mol

molar mass of MgF₂ = 62.3 g/mol

Using the molar mass we can find the number of moles that we have in 6.73 mg or 0.00673 g of MgF₂:

moles of MgF₂ = 0.00673 g/(62.3 g/mol)

moles of MgF₂ = 1.08 * 10^-4 moles

So the chemist added 1.08 * 10^-4 moles of MgF₂ in 0.250 L of solution. Then the molarity of the solution is:

Molarity = moles of solute/Volume of solution in L

Molarity = 1.08 * 10^-4 moles/0.250 L

Molarity = 4.32 * 10^-4 M

So the answer to our problem is 4.32 * 10^-4 M

A quasar is a star that emits intense radio and light energy.

A quasar is an extremely bright radio source. It is called a quasi-stellar radio source. It appears to be like a star but is not a star. These quasars are young galaxies that are located far away from us and are highly luminous. The luminosity of a quasar is 1000 times greater than the luminosity of a milky way galaxy.

A quasar is powered by a supermassive black hole with its mass ranging from millions to tens of billions of solar masses, surrounded by a gaseous accretion disc.

The quasars were first discovered in the 1950s using the Hubble space telescope and were found to be a massive bright source emitting radio waves of unknown origin. But now, millions of quasars were discovered.

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The sum of coefficients when the above-mentioned equation is balanced is 12.

A chemical equation is a symbolic representation of a chemical reaction where reactants are represented on the left, and products on the right.

A chemical equation is said to be balanced when the number of atoms of each element on both sides of the equation is the same.

According to this question, calcium hydroxide reacts with phosphoric acid as follows:

3Ca(OH)₂ + 2H₃PO4 → Ca₃(PO4)₂ + 6H₂O

The sum of the coefficients of the above balanced chemical equation is 3 + 2 + 1 + 6 = 12.

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Of the options given, the correct one for the Lewis structure of CO₂ is option A.  

In the covalent structure of CO₂, each atom will tend to have 8 electrons on its side, in order to comply with the octet rule. In this rule, an atom that has 8 electrons in its valence shell, will gain stability for having a noble gas electronic configuration.      

Hence, the correct lewis structure for CO₂ is option A. In this configuration, each atom has 8 electrons on its side and all of them are neutral (the total charge of the molecule is zero). They all achieve the octet rule.    

Although in option B all the atoms have 8 electrons (thus complying with the octet rule), in this configuration the oxygen atom on the left has a negative charge (-1) and the oxygen on the right side has a positive charge (+1). The total charge on the molecule is zero (it is neutral). In fact, this is a resonance structure of configuration A.    

In option C, the total charge of the molecule is -2, so this is not a stable configuration. The number of electrons on carbon is wrong.  

Finally, in option D the oxygen on the right side does not achieve the octet rule (it only has 6 electrons shared), and also the carbon atom has a charge of -2, and the oxygens have charges of -1 (left) and +3 (right), so this is not a stable configuration.  

Therefore, the correct lewis structure for CO₂ is option A.

The final pressure of the gas when the sample gas is administered to a new volume of 10.0 L at 20.2℃ would be 0.245 atm.

The problem here has to do with the combined gas law. The law is mathematically expressed as:

[tex]p_1v_1/t_1[/tex] =[tex]p_2v_2/t_2[/tex]

Where [tex]p_1[/tex] = initial pressure, [tex]v_1[/tex] = initial volume, [tex]t_1[/tex] = initial temperature, [tex]p_2[/tex] = final pressure, [tex]v_2[/tex] = final volume, and [tex]t_2[/tex] = final temperature.

In this case,

Rearranging the combined gas equation:

[tex]p_2[/tex] = [tex]p_1v_1t_2/t_1v_2[/tex]

Substituting the different variables:

[tex]p_2[/tex] = 1.2 x 6.02 x 20.2/59.5 x 10.0

      = 145.9248/595

      = 0.245 atm

Thus, the final pressure of the sample gas will be 0.245 atm.

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Answer

The pressure of the sample is 1.47 atm

Explanation

Given:

Moles, n = 1.31 mol

Volume, V = 24.6 L

Temperature, T = 336 K

The ideal gas constant, R = 0.0821 L*atm/mol*K

What to find:

Pressure, P of the sample.

Step-by-step solution:

Pressure, P of the sample can be calculated using the ideal gas equation.

Put the values of the parameters into the formula, we have;

The pressure of the sample is 1.47 atm

Answer:

All atoms of a specific element are identical in mass, size, and other properties. However, atoms of different element exhibit different properties and vary in mass and size. Atoms can neither be created nor destroyed. Furthermore, atoms cannot be divided into smaller particles.

Explanation:

We form a supersaturated solution. At 45 °C the solution has more potassium nitrate that can be dissolved. The recrystallization of the excess dissolved solute can be started inserting a crystal that is called seed crystal.

Answer: seed

PO₄ appears in two different places in this chemical equation. PO₃⁻⁴ is a polyatomic ion called phosphate. 2 should be placed in front of Na₃PO₄ to give the same total number of phosphate ions on each side of the equation.

For the reaction -

? Na₃PO₄ + MgCl₂  →  Mg₃(PO₄)₂ + NaCl

There are 2 phosphate ions present on the product side, therefore, 2 phosphate atoms should be present on the reactant side to maintain the equilibrium.

On product side, number of ions of magnesium is 3, so to attain the equilibrium and balance the equation there 3 ions of magnesium should be on the reactant side.

In order to balance the number of ions of phosphate and magnesium in the reaction which is given -

On the reactant side, 6 atoms of chlorine and sodium are formed, in order to balance these 6 atoms of chlorine and sodium, 6 atoms of each should be present on the product side.

Therefore, the balanced chemical equation is -

2 Na₃PO₄ + 3 MgCl₂  →  Mg₃(PO₄)₂ + 6 NaCl

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Answer:

c

Explanation:

V atery few members of the public have heard of a case dealing with forensics. The use of forensics is more popular with the public and law enforcement. Colleges have stopped offering courses and majors in forensic science.

In order to solve this question we need to set up the properly balanced equation first:

CaCO3 + 2 HCl -> CaCl2 + H2O + CO2

Now that our reaction is properly balanced, we have to find the limiting reactant in order to find how much mass of CaCl2 will be produced

We have:

10.0 g of CaCO3, molar mass = 100.086 g/mol

15.0 g of HCl, molar mass = 36.46 g/mol

Now we need to find the number of moles of the reactants, and see if the amount available of the other reactant is the one needed to react.

CaCO3:

100.086g = 1 mol

10g = x moles

x = 0.099 moles of CaCO3

According to the molar ratio, the CaCO3 and HCl will have a relationship in which we will always need 2 times more HCl than CaCO3, therefore if we have 0.099 moles of CaCO3, we will need 0.198 moles of HCl in order to proceed with the reaction, but we don't know if that is the right amount, let's check:

HCl:

36.46g = 1 mol

15.0g = x moles

x = 0.411 moles of HCl, this means that we have an excess of HCl, since we only need 0.198 moles in order to react with CaCO3. Therefore Calcium carbonate is the limiting reactant.

Now that we know which one is the limiting reactant, we can find the mass produced of CaCl2.

Again the molar ratio is important here, but know, we will always have the same number of moles for CaCO3 and CaCl2, 1:1 will be the molar ratio, therefore if we have 0.099 moles of CaCO3, we will also have 0.099 moles of CaCl2, using its molar mass, 110.978g/mol, we can find the final mass

CaCl2:

110.978g = 1 mol

x grams = 0.099 moles

x = 11.0 grams (it is actually 10.986 grams, but I have rounded up to 11 grams)