A cylinder contains 27.0 L of oxygen gas at a pressure of 1.7 atm and a temperature of 285 K . Part A How much gas (in moles) is in the cylinder? Express your answer using two significant figures.

Answer:

Wavelength, λ  = 6.7 x 10^-11 m

Explanation:

Frequency and wavelength are inversely proportional to each other.

In this problem;

f =  4.5 x 10^18 Hz

wavelength, λ = ?

Speed of light, c = 3 x 108 m/s.

These variables are related by the following equation;

c = λ * f

Making λ subject of focus, we have;

λ = c / f

λ = 3 x 10^8 / 4.5 x 10^18

λ  = 0.67 x 10^-10

λ  = 6.7 x 10^-11 m

Answer:

B) It must be a weak acid.

Explanation:

If HA is a strong acid

[tex]HA\rightleftharpoons H^++A^-[/tex]

Now the pH value can be written as follows

[tex]pH=-log[H^+]\\pH=-log(5\times 10^{-2})\\pH=2\times log5\\pH=1.4[/tex]

But given that acid HA has 2.3 pH value.

Therefore we can say that HA is weak acid.

Thus the answer will be option (B).

B) It must be a weak acid.

Answer:

1.30atm

Explanation:

P1/T1 = P2/T2

1.07/393 = P2/478

Answer: the first one is correct

Explanation:

jhkfjfjgjgjjggj

Answer: 1 mole per L

Explanation:

(2M)(500mL)=(M)(1000mL)

1000=(M)(1000mL)

M=1

Taking into account the definition of dilution, if 500 mL of 2.0 M HCl is diluted with water to a volume of 1 liter, the molarity of the new solution is 1 M.

When it is desired to prepare a less concentrated solution from a more concentrated one, it is called dilution.

Dilution is the process of reducing the concentration of solute in solution, which is accomplished by simply adding more solvent to the solution at the same amount of solute.

In a dilution the amount of solute does not change, but as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.

A dilution is mathematically expressed as:

where

In this case, you know:

Replacing in the definition of dilution:

2.0 M× 500 mL= Cf× 1000 mL

Solving:

(2.0 M× 500 mL)÷ 1000 mL= Cf

1 M= Cf

In summary, if 500 mL of 2.0 M HCl is diluted with water to a volume of 1 liter, the molarity of the new solution is 1 M.

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A. Dalton's theory that atoms could not be divided was incorrect

Answer: A

Explanation:

Explanation:

[tex]8.01 \times {10}^{22} \times \frac{1}{6.02 \times {10}^{23} } \times \frac{22.4}{1} = 2.9804[/tex]

Answer:

First convert volume given into same unit.

Therefore 1000 mL =1L

1000mL=1L

25.0mL=?

(25.0×1)÷1000=0.025L

but using the equation;M1×V1=M2×V2

M1=14.2M

V1=0.025L

M2=?

V2=0.5L

Therefore;. 14.2×0.025=M2×0.5

M2=(14.2×0.025)÷0.5

M2=0.71M.

A stock solution of HNO3 is prepared and found to contain 14.2 M of HNO3. If 25.0 mL of the stock solution is diluted to a final volume of 0.500 L, the concentration of the diluted solution is 0.71M.

To make a stock solution, weigh out the proper amount of a pure solid or measure out the proper amount of a pure liquid, put it in the right flask, and then dilute it to the desired volume. Depending on the intended concentration unit, many methods can be used to measure the reagent.

First we convert volume

Then 1000 mL = 1L

1000mL= 1L

25.0mL = ?

( 25.0 × 1 ) / 1000

= 0.025L

by using the equation;

M1 × V1 = M2 × V2

M1 = 14.2M

V1 = 0.025L

M2 = ?

V2 = 0.5L

14.2 × 0.025 = M2 × 0.5

M2 = (14.2 × 0.025 ) ÷ 0.5

M2 = 0.71M.

Thus, A stock solution of HNO3 is prepared and found to contain 14.2 M of HNO3. If 25.0 mL of the stock solution is diluted to a final volume of 0.500 L, the concentration of the diluted solution is 0.71M.

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Answer:

If gold has a rare, high density then it would sink quickly. If mixed substances that are less-valued, are added to the gold crown (remember that gold is rare and very dense which makes it special) then we can assume the cheap substances are less dense, thus making the crown FLOAT more rather than sink (I say more, because unless the crown was extremely mixed with cheap material then it could possibly float but it depends on how much is in the crown). Summary: The crown would either be lighter and float, or barely be sunken due to the less-dense substance.

*Hint to think about: People consider cheaper things lighter such as plastic ring/less dense  for example, compared to a silver ring which is heavier/more dense (btw heavy does not always mean high density, it depends on the liquid density )

Hope this actually helps!

Explanation:

High-Desnity=Sink

Low Density=Float

Answer:

Number of moles = 0.1058 mol

Explanation:

Density = 1.08 g/mL

Volume = 10ml

Density = Mass / Volume

Mass = Density * Volume

Mass = 1.08 * 10 = 10.8g

The molar mass of acetic anhydride = 102.09 g/mol

Molar mass = Mass / Moles

Upon solving for moles;

Moles = Mass / Molar mass

Moles = 10.8 / 102.09 = 0.1058 mol

The moles of acetic acid used in the experiment has been 0.1058 mol.

Density has been defined as mass of a substance per unit volume. The density has been expressed as:

[tex]\rm Density=\dfrac{Mass}{Volume} [/tex]

The moles have been the mass of the substance with respect to the molar mass. The moles of a substance has been given as:

[tex]\rm Moles=\dfrac{Mass}{Molar\;mass} [/tex]

The given sample of acetic acid has density = 1.08 g/ml

The volume of the sample used in the experiment has been 10 ml.

Substituting the values for the mass of acetic acid:

[tex]\rm 1.08=\dfrac{Mass}{10}\\ Mass=1.08\;\times\;10\;g\\ Mass=10.8\;g[/tex]

The mass of the acetic acid used has been 10.8 g.

The molar mass of acetic acid has been 102.09 g/mol.

Substituting the values for the moles of acetic acid:

[tex]\rm Moles=\dfrac{10.8}{102.09} \\ Moles=0.1058\;mol[/tex]

The moles of acetic acid used in the experiment has been 0.1058 mol.

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Answer: The [tex][OH^-][/tex] of a solution is [tex]10^{-12}[/tex] M

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]

where,

n = moles of solute

[tex]V_s[/tex] = volume of solution in ml

moles of [tex]HCl[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{0.0912g}{36.5g/mol}=0.0025mol[/tex]

Now put all the given values in the formula of molality, we get

[tex]Molarity=\frac{0.0025\times 1000}{250}=0.01[/tex]

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

[tex]HCl\rightarrow H^++Cl^{-}[/tex]

According to stoichiometry,

1 mole of [tex]HCl[/tex] gives 1 mole of [tex]H^+[/tex]

Thus [tex]0.01[/tex] moles of [tex]HCl[/tex] gives =[tex]\frac{1}{1}\times 0.01=0.01[/tex] moles of [tex]H^+[/tex]

Putting in the values:

[tex][H^+][OH^-]=10^{-14}[/tex]

[tex][0.01][OH^-]=10^{-14}[/tex]

[tex][OH^-]=10^{-12}[/tex]

Thus the [tex][OH^-][/tex] of a solution prepared by dissolving 0.0912 g of hydrogen chloride in sufficient pure water to prepare 250.0 ml of solution is [tex]10^{-12}[/tex] M

The  [OH-] of a solution is [tex]10^{12}[/tex] M.

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

M = n/ V..................(1)

where,

n = moles of solute

V = volume of solution in ml

Calculation for number of moles:

Moles of HCl =  0.0912 g/ 36.5 g/mol = 0.0025 mol

On substituting the values in equation 1:

M = n/ V

M= 0.0025*1000 / 250

M=0.01 M

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

[tex]HCl---- > H^++Cl^-[/tex]

According to stoichiometry,

1 mole of HCl  gives 1 mole of [tex]H^+[/tex]

Thus, 0.01 moles of HCl gives =  1 / 1 *0.01 = 0.01 mole of [tex]H^+[/tex]

On adding the values:

[tex][H^+][OH^-]=10^{14}\\\\(0.01)[OH^-]=10^{-14}\\\\OH^-=10^{-12}[/tex]

Thus, the [OH-]  of a solution prepared by dissolving 0.0912 g of hydrogen chloride in sufficient pure water to prepare 250.0 ml of solution is [tex]10^{-12}[/tex]  M.

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Answer:

0.623 M

Explanation:

Step 1: Given data

Step 2: Calculate the percent by volume (%m/v)

We will use the following expression.

[tex]\%m/v = \%m/m \times \rho = 7.00\% \times 1.071g/mL = 7.50g\%mL[/tex]

Step 3: Calculate the molarity

7.50 g of magnesium sulfate are dissolved in 100 mL of the solution. The molarity is:

[tex]M = \frac{7.50g}{120.37g/mol \times 0.100L } = 0.623 M[/tex]

Answer:

[tex]Pb(CO_{3})_{2} \\Pb(NO_{3})_{4} \\FeCO_{3}\\Fe(NO_{3})_{2}[/tex]

Explanation:

[tex]Pb^{4+}(CO_{3}^{2-})_{2} --->Pb(CO_{3})_{2} \\Pb^{4+} (NO_{3}^{-})_{4} --->Pb(NO_{3})_{4} \\Fe^{2+} CO_{3}^{2-} --->FeCO_{3}\\Fe^{2+} (NO_{3}^{-})_{2}--->Fe(NO_{3})_{2}[/tex]

Explanation:

[tex]=\dfrac{1.0505\times 10^{23}}{6.022\times 10^{23}}\times 44\\\\=7.675\ \text{grams}[/tex]

Answer:

[Ni(CN)4]2- square planar

[NiCl4]2- tetrahedral

Explanation:

For a four coordinate complex such as [Ni(CN)4]2- and [NiCl4]2-, we can decide its geometry by closely considering its magnetic properties. Both of the complexes are d8 complexes which could be found either in the tetrahedral or square planar crystal field depending on the nature of the ligand.

CN^- being a strong field ligand leads to the formation of a square planar diamagnetic d8 complex of Ni^2+. Similarly, Cl^- being a weak field ligand leads to the formation a a tetrahedral paramagnetic d8 complex of Ni^+ hence the answer given above.

Answer:

The correct answer is 1.17 moles

Explanation:

The ideal gas equation combines the pressure (P), volume (V), temperature (T) and number of moles of a gas (n):

PV= nRT

R is the gas constant (0.082 L.atm/K.mol)

In this case, we have:

V= 7.2 L

P= 4.0 atm

T= 27ºC + 273 = 300 K

We calculate the number of moles (n) of gas as follows:

n= (PV)/(RT)= (4.0 atm x 7.2 L)/(0.082 L.atm/K.mol x 300 K) = 1.17 mol

Answer:

The metal with the lowest specific heat capacity

Explanation:

Hello, this question can be solved when we compare their specific heat capacities.

Specific heat capacity of a metal /substance is the heat required to raise it's temperature by one degree Celsius.

Mathematically,

Q = mc∇θ

Q = heat energy applied

M = mass of the metal

C = specific heat capacity of the metal

∇θ = (θ₂ - θ₁) which corresponds to the change in temperature of the metal.

In a given experiment of different metals with different specific heat capacities, assuming they're of equal mass and same amount of energy is applied with the same amount of initial temperature, the metal with the lowest specific heat capacity would have the highest final temperature likewise the metal with the highest specific heat capacity would have the lowest final temperature.

The is due to the energy required to raise the temperature of the metal by 1°C

Answer:

A, B and C are compounds

Explanation:

First of all, I need to establish that when carbon is burnt in excess oxygen, carbon dioxide is obtained as shown by this equation; C(s) + O2(g) ----> CO2(g).

Looking at the presentation in the question, A was said to be heated strongly and it decomposed to B and C. Only a compound can decompose when heated. Elements can not decompose on heating. Secondly, compounds usually decompose to give the same compounds that combined to form them. Compounds hardly decompose into their constituent elements.

Again from the information provided, the compound A is a white solid. This is likely to be CaCO3. It decomposes to give another white solid. This may be CaO and the gas was identified as CO2.

Hence;

CaCO3(s)--------> CaO(s) + CO2(g)

Answer:

[tex]T=1235K=962\°C[/tex]

Explanation:

Hello,

In this case, from thermodynamics, it is widely known that the entropy of fusion is defined in terms of the enthalpy of fusion at the fusion temperature (melting point) as shown below:

[tex]\Delta _fS=\frac{\Delta _fH}{T}[/tex]

Thus, solving for the melting point:

[tex]T=\frac{\Delta _fH}{\Delta _fS}[/tex]

Hence, for silver:

[tex]T=\frac{11.30kJ/(mol)*\frac{1000J}{1kJ} }{9.150J/(mol*K)} \\\\T=1235K=962\°C[/tex]

Which is a typical high temperature for a metal such as silver.

Best regards.

Answer:

Heating the mixture to a temperature above the boiling point of acetic acid, but below 100°C (the boiling point of water). The vapours from the acetic acid rise, and go into a tube. They are then condensed within the tube, and run off into a separate storage area. Because water can exist as a gas at pretty much any temperature above 0°C, it will result in an impure mixture, but repeatedly doing this will get the acetic acid to the desired purity.

Answer:

193.07 g / mol

Explanation:

Molar mass of (NH₄)₃ = 3 * (14.01 + 4 * 1.01) = 54.15

As = 74.92 and O₄ = 4 * 16 = 64

Answer is 54.15 + 74.92 + 64 = 193.07

Answer:

(a).molar mass=(12×9)+(1×8)+(16×4)

=180.0g

(b).moles of Aspirin

moles=mass(g)÷molar mass

=360.4÷180.0

=2.002moles

(c). molecules of Aspirin

To get molecules just multiply moles of Aspirin by Avocado number.

=2.002×6.022×10^23

=1.206×10^24 molecules

(d) number of carbon atoms

=12×9

=108 carbon

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, the mole of aspirin is 2.002moles.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

Mathematically,

molar mass=(mass of carbon atom×9)+(mass of hydrogen atom1×8)+(mass of oxygen atom×4)

                 =(12×9)+(1×8)+(16×4)

                  =180.0g/mol

moles=mass ÷molar mass

          =360.4÷180.0

           =2.002moles

molecules of Aspirin=moles×6.022×10²³

                                  =2.002×6.022×10²³

                                 =1.206×10²⁴ molecules

number of carbon atoms=12×9

                                       =108 carbon

Therefore, the mole of aspirin is 2.002moles.

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Answer:

88.9%

Explanation:

Step 1:

The balanced equation for the reaction. This is given below:

2AlCl3(aq) + 3H2SO4(aq) —> Al2(SO4)3(aq) + 6HCl(aq)

Step 2:

Determination of the masses of AlCl3 and H2SO4 that reacted and the mass of Al2(SO4)3 produced from the balanced equation.

Molar mass of AlCl3 = 27 + (35.5x3) = 133.5g/mol

Mass of AlCl3 from the balanced equation = 2 x 133.5 = 267g

Molar mass of H2SO4 = (2x1) + 32 + (16x4) = 98g/mol

Mass of H2SO4 from the balanced equation = 3 x 98 = 294g

Molar mass of Al2(SO4)3 = (27x2) + 3[32 + (16x4)]

= 54 + 3[32 + 64]

= 54 + 3[96] = 342g/mol

Mass of Al2(SO4)3 from the balanced equation = 1 x 342 = 342g

Summary:

From the balanced equation above,

267g of AlCl3 reacted with 294g of H2SO4 to produce 342g of Al2(SO4)3.

Step 3:

Determination of the limiting reactant. This is illustrated below:

From the balanced equation above,

267g of AlCl3 reacted with 294g of H2SO4.

Therefore, 25g of AlCl3 will react with = (25 x 294)/267 = 27.53g of H2SO4.

From the calculations made above, we see that only 27.53g out 30g of H2SO4 given were needed to react completely with 25g of AlCl3.

Therefore, AlCl3 is the limiting reactant and H2SO4 is the excess.

Step 4:

Determination of the theoretical yield of Al2(SO4)3.

In this case we shall be using the limiting reactant because it will produce the maximum yield of Al2(SO4)3 since all of it is used up in the reaction.

The limiting reactant is AlCl3 and the theoretical yield of Al2(SO4)3 can be obtained as follow:

From the balanced equation above,

267g of AlCl3 reacted to produce 342g of Al2(SO4)3.

Therefore, 25g of AlCl3 will react to produce = (25 x 342) /267 = 32.02g of Al2(SO4)3.

Therefore, the theoretical yield of Al2(SO4)3 is 32.02g

Step 5:

Determination of the percentage yield of Al2(SO4)3.

This can be obtained as follow:

Actual yield of Al2(SO4)3 = 28.46g

Theoretical yield of Al2(SO4)3 = 32.02g

Percentage yield of Al2(SO4)3 =..?

Percentage yield = Actual yield /Theoretical yield x 100

Percentage yield = 28.46/32.02 x 100

Percentage yield = 88.9%

Therefore, the percentage yield of Al2(SO4)3 is 88.9%

Answer:

a lower temperature to liquefy

Explanation:

Answer:

[tex]C_4H_{10}O[/tex]

Explanation:

Hello,

In this case, the first step is to compute the moles of carbon in the sample that are contained in CO2 only at the products as shown below:

[tex]n_C=8.612gCO_2*\frac{1molCO_2}{44gCO_2} *\frac{1molC}{1molCO_2} =0.196molC[/tex]

Next the moles of hydrogen contained in the H2O only:

[tex]n_H=4.406gH_2O*\frac{1molH_2O}{18gH_2O} *\frac{2molH}{1molH_2O} =0.490molH[/tex]

Now, we compute the mass of oxygen in the sample, by subtracting mass of both carbon and hydrogen from the 3.626 g of sample:

[tex]m_O=3.626g-0.196molC*\frac{12gC}{1molC}-0.490molH*\frac{1gH}{1molH} =0.784gO[/tex]

And the moles:

[tex]n_O=0.784gO*\frac{1molO}{16gO} =0.049molO[/tex]

Now, the mole ratios by considering the moles of oxygen as the smallest:

[tex]C=\frac{0.196mol}{0.049mol}= 4\\\\H=\frac{0.49mol}{0.049mol}=10\\\\O=\frac{0.049mol}{0.049mol}=1[/tex]

Thus, empirical formula is:

[tex]C_4H_{10}O[/tex]

Regards.

Combining quantum theory with wave motion of atomic particles is: Wave Mechanics

Answer:

I would put A

Explanation:

A new substance is produced as a result of a chemical reaction in which bonds between the molecules of the reactant and product are broken and new bonds are formed. Here the products are Al₂O₃ and Fe. The correct option is A.

Chemical reactions are interactions between two or more molecules that result in the production of new products. Products, as opposed to reactants, are compounds that result from an interaction between two other substances.

The reactants are on the left, while the products that are created are on the right. A one-headed or two-headed arrow connects the reactants and products.

Thus the correct option is A.

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Answer:

d

Explanation:

Answer:

Option D is correct.

n = 6 to n = 2

Explanation:

Like all waves emitted from the movement of electrons from one energy level to another, the wavelength (λ) is given by the equation involving Rydberg's constant

(1/λ) = Rₕ [(1/n₂²) - (1/n₁²)]

where Rₕ = 10973731.57 m⁻¹ = (1.0974 × 10⁷) m⁻¹

n₂ = principal quantum number corresponding to the final energy level of the electron = 2 (For Balmer Series)

n₁ = principal quantum number corresponding to the final energy level of the electron = ?

λ = 410 nm = (410 × 10⁻⁹) m

(1/λ) = (2.439 × 10⁶) m⁻¹

2.439 × 10⁶ = (1.0974 × 10⁷) [(1/2²) - (1/n₁²)]

0.25 - (1/n₁²) = (2.439 × 10⁶) ÷ (1.0974 × 10⁷) = 0.2222602562

(1/n₁²) = 0.25 - 0.2222602562 = 0.0277397438

n₁² = (1/0.0277397438) = 36.05

n₁ = 6

Hope this Helps!!!

Answer:

33.3% of Sn in the sample

Explanation:

The addition of SO₄⁻ ions produce the selective precipitation of Pb²⁺ to produce PbSO₄.

Moles of PbSO₄ (molar mass 303.26g/mol) in 2.93g are:

2.93g ₓ (1mol / 303.26) = 9.66x10⁻³ moles PbSO₄ = Moles Pb²⁺.

As molar mass of Pb is 207.2g/mol, mass in 9.66x10⁻³ moles of Pb²⁺ is:

9.66x10⁻³ moles of Pb²⁺ ₓ (207.2g / mol) = 2.00g of Pb²⁺

As mass of the sample is 3.00g, mass of Sn²⁺ is 3.00g - 2.00g = 1.00g

And the percentage of Sn in the sample is:

1.00g / 3.00g ₓ 100 =

Answer:

"The active site of the enzyme has a complementary rigid structure" belongs to the key and lock system

"The conformation of the enzyme changes when it binds to the substrate so that the active site conforms to the substrate." belongs to the induced fit system.

"The substrate binds to the enzyme at the active site, forming an enzyme-substrate complex" belongs to both, that is, the key and lock system and the induced fit system.

"The substrate binds to the enzyme through non-covalent interactions" can belong to both enzyme systems.

Explanation:

Enzymatic key and lock systems bear this name because the enzyme at its site of union with the substrate has an ideal shape so that its fit is perfect, similar to a headbreaker, so once they are joined they are not It can bind another substrate to the enzyme, since they are generally associated with strong chemical bonds.

The shape of the enzyme's active site is a negative of what the shape of the substrate would be.

On the other hand, in the mechanism or enzyme system of induced adjustment, the enzyme has an active site that is where it binds with the substrate and another site where another chemical component binds, which when this chemical component binds this enzyme changes its morphology and becomes "active" to bond with your substrate.

This happens a lot in the inactive enzymes that are usually activated in digestive processes since the fact that these enzymes are constantly active would be dangerous, therefore the body takes the induced enzyme system as a control mechanism, where a molecule or chemical compound induces change morphological of an enzyme by means of the allosteric union so that it joins its substrate and catalyzes or analyzes it, depending on the enzymatic character of the enzyme.