A 3.52g sample of chromium metal reacts with fluorine to produce 7.38g of metal fluoride. What is the mass % of Cr in the metal fluoride?

Answer:

Amount of ethyl butyrate formed = 11.3 g

Explanation:

The reaction between butanoic acid (C3H7COOH) and excess ethanol (C2H5OH) is:

[tex]C3H7COOH + C2H5OH \rightarrow C3H7COOC2H5 + H2O[/tex]

Since ethanol is the excess reagent, the formation of the product i.e. ethyl butyrate is influenced by the amount of butanoic acid present

Based on the reaction stoichiometry:

1 mole of butanoic acid produces 1 mole of ethyl butyrate

Mass of butanoic acid = 8.50 g

Molar mass of butanoic acid = 88 g/mol

[tex]Moles\ of \ butanoic\  acid = \frac{Mass}{Molar\ mass} =\frac{8.50g}{88g/mol}=0.097 moles[/tex]

Moles of ethyl butyrate = 0.097

Molar mass of ethyl butyrate= 116 g/mol

[tex]Mass\ of\ ethyl\  butyrate= 0.097*116 = 11.3 g[/tex]

Answer:

If we have 29 quibs of skvarnick they will be equal to 11.6 sleps.

Explanation:

Mass of a substance called skvarnick = 29 quibs

10 quibs is equal to 4 sleps. This means that 1 quibs is equal to 0.4 sleps.

10 quibs = 4 sleps

1 quibs = [tex]\frac{4}{10} sleps = 0.4 sleps[/tex]

Then 29 quibs will be:

[tex]29 quibs=29\times 0.4 sleps =11.6 sleps[/tex]

If we have 29 quibs of skvarnick they will be equal to 11.6 sleps.

The two Lewis structure for a compound with the formula [tex]\rm C_4H_{10}[/tex] are shown below in the attached image.

In a Lewis structure, an element's chemical symbol shows its nucleus and inner electrons, while dots or lines represent valence electrons. Valence electrons are the atom's outermost electrons and are important in chemical bonding.

Therefore, the two structure of [tex]\rm C_4H_{10}[/tex] are isomers of each other (refer to the attached image).

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The answer is: mass of the snack mix can you consume and still be within the FDA limit is 491 grams.

ω(Na) = m(Na) ÷ m(salt).

ω(Na) = 39.33 g ÷ 100 g.

ω(Na) = 0.3933; mass percentage of sodium in salt.

m(salt) = 2.4 g ÷ 0.3933.

m(salt) = 6.10 g; mass of salt recommended for consumation.

Make proportion: 1.24 g : 100 g = 6.10 g ÷ m(mix).

m(mix) = 491.93 g; mass of the snack mix.

Explanation:

According to the mole concept, there are [tex]6.022 \times 10^{22}[/tex] atoms present.

It is given that mass is 0.250 g. And, number of moles are equal to mass divided by molar mass.

Mathematically,       No. of moles = [tex]\frac{mass}{\text{molar mass}}[/tex]

As molar mass of [tex]P_{2}O_{5}[/tex] is 283.88 g/mol. Therefore, putting given values into the above formula as follows.

                 No. of moles = [tex]\frac{mass}{\text{molar mass}}[/tex]

                                       = [tex]\frac{0.250 g}{283.88 g/mol}[/tex]

                                       = 0.0008 mol

Hence, number of atoms present in 0.0008 mol are as follows.

                      [tex]0.0008 mol \times 6.022 \times 10^{22} atoms/mol[/tex]

                     = 0.0048 atoms

Thus, we can conclude that there are 0.0048 atoms in 0.250 g of [tex]P_{2}O_{5}[/tex].

n = 6 to n = 2

From several sources, we have prepared the following answer choices:

A. n = 2 to n = 5  

B. n = 6 to n = 4  

C. n = 3 to n = 2  

D. n = 6 to n = 2  

We will determine which electron transition would correspond to the shortest wavelength line in the visible emission spectra for hydrogen.  

The amount of energy released or absorbed by electrons when moving from n₁ level to n₂ level is equal to  

[tex]\boxed{ \ \Delta E = -13.6 \Big( \frac{1}{n_2^2} - \frac{1}{n_1^2} \Big) \ }[/tex]  in eV.

This energy difference is equal to [tex]\boxed{ \ hf = \frac{hc}{\lambda} \ }[/tex], where f and λ are the frequency and wavelength of the radiation emitted or absorbed.

Thus, the wavelength is inversely proportional to the energy difference from the electron transition. To get the shortest wavelength, it is determined by the largest ΔE.  

From the formula above, we practically only need to calculate part [tex]\boxed{ \ \Big( \frac{1}{n_2^2} - \frac{1}{n_1^2} \Big) \ }[/tex] which is directly proportional to ΔE.  Then from the results of the calculation of this section, we will get the shortest wavelength from the largest result..

A. n₁ = 2 to n₂ = 5  

[tex]\boxed{ \ \Big( \frac{1}{5^2} - \frac{1}{2^2} \Big) \ }[/tex]  

[tex]\boxed{ \ -\frac{21}{100} \ }[/tex]

By taking the absolute value, we get [tex]\boxed{ \ 0.210 \ }[/tex]

B. n₁ = 6 to n₂ = 4  

[tex]\boxed{ \ \Big( \frac{1}{4^2} - \frac{1}{6^2} \Big) \ }[/tex]  

[tex]\boxed{ \ \frac{5}{144} \ }[/tex]

We get [tex]\boxed{ \ 0.0347 \ }[/tex]

C. n₁ = 3 to n₂ = 2  

[tex]\boxed{ \ \Big( \frac{1}{2^2} - \frac{1}{3^2} \Big) \ }[/tex]  

[tex]\boxed{ \ \frac{5}{36} \ }[/tex]

We get [tex]\boxed{ \ 0.1389 \ }[/tex]

D. n₁ = 6 to n₂ = 2  

[tex]\boxed{ \ \Big( \frac{1}{2^2} - \frac{1}{6^2} \Big) \ }[/tex]  

[tex]\boxed{ \ \frac{2}{9} \ }[/tex]

We get [tex]\boxed{ \ 0.222 \ }[/tex]

The last calculation above shows the greatest results so that the shortest wavelength is undoubtedly gained from the electron transition n = 6 to n = 2.

Keywords: according to the Bohr model of the atom, which electron transition would correspond, to the shortest wavelength, the visible emission spectra for hydrogen, energy, inversely proportional

The electronic transition from [tex]\boxed{{\text{D}}{\text{. n}} = {\text{6 to n}} = {\text{2}}}[/tex] corresponds to the shortest wavelength.

Further explanation:

Rydberg equation describes the relation of wavelength of spectral line with the transition values. The expression for Rydberg equation is as follows:

[tex]\dfrac{1}{\lambda } = \left( {{{\text{R}}_{\text{H}}}} \right)\left( {\dfrac{1}{{{{\left( {{{\text{n}}_{\text{1}}}} \right)}^2}}} - \dfrac{1}{{{{\left( {{{\text{n}}_{\text{2}}}} \right)}^2}}}} \right)[/tex]  …… (1)                                                  

Here,

[tex]\lambda[/tex] is the wavelength of spectral line

[tex]{{\text{R}}_{\text{H}}}[/tex] is Rydberg constant that has the value  

[tex]{{\text{n}}_{\text{1}}}[/tex] and [tex]{{\text{n}}_{\text{2}}}[/tex] are the two positive integers, where  .

Rearrange equation (1) to calculate  .

[tex]\lambda = \dfrac{1}{{\left( {1.097 \times {{10}^7}{\text{ }}{{\text{m}}^{ - 1}}} \right)\left( {\dfrac{1}{{{{\left( {{{\text{n}}_1}} \right)}^2}}} - \dfrac{1}{{{{\left( {{{\text{n}}_{\text{2}}}} \right)}^2}}}} \right)}}[/tex]                                        …… (2)

A. n = 2 to n = 5

Substitute 2 for [tex]{{\text{n}}_{\text{1}}}[/tex] and 5 for [tex]{{\text{n}}_{\text{2}}}[/tex] in equation (2).

 [tex]\begin{aligned}\lambda&= \frac{1}{{\left( {1.097 \times {{10}^7}{\text{ }}{{\text{m}}^{ - 1}}} \right)\left( {\frac{1}{{{{\left( 2 \right)}^2}}} - \frac{1}{{{{\left( 5 \right)}^2}}}} \right)}} \\&= 4.34 \times {10^{ - 7}}{\text{ m}}\\\end{aligned}[/tex]

B. n = 6 to n = 4

Substitute 4 for [tex]{{\text{n}}_{\text{1}}}[/tex] and 6 for [tex]{{\text{n}}_{\text{2}}}[/tex] in equation (2).

 [tex]\begin{aligned}\lambda&= \frac{1}{{\left( {1.097 \times {{10}^7}{\text{ }}{{\text{m}}^{ - 1}}} \right)\left( {\frac{1}{{{{\left( 4 \right)}^2}}} - \frac{1}{{{{\left( 6 \right)}^2}}}} \right)}}\\&= 2.63 \times {10^{ - 6}}{\text{ m}}\\\end{aligned}[/tex]

C. n = 3 to n = 2

Substitute 2 for [tex]{{\text{n}}_{\text{1}}}[/tex] and 3 for [tex]{{\text{n}}_{\text{2}}}[/tex] in equation (2).

 [tex]\begin{aligned}\lambda  &= \frac{1}{{\left( {1.097 \times {{10}^7}{\text{ }}{{\text{m}}^{ - 1}}}\right)\left( {\frac{1}{{{{\left( 2 \right)}^2}}} - \frac{1}{{{{\left( 3 \right)}^2}}}} \right)}} \\ &= 6.56 \times {10^{ - 7}}{\text{ m}}\\\end{aligned}[/tex]

D. n = 6 to n = 2

Substitute 2 for [tex]{{\text{n}}_{\text{1}}}[/tex] and 6 for [tex]{{\text{n}}_{\text{2}}}[/tex] in equation (2).

 [tex]\begin{aligned}\lambda&= \frac{1}{{\left( {1.097 \times {{10}^7}{\text{ }}{{\text{m}}^{ - 1}}} \right)\left({\frac{1}{{{{\left( 2 \right)}^2}}} - \frac{1}{{{{\left( 6 \right)}^2}}}}\right)}} \\&= 4.10 \times {10^{ - 7}}{\text{ m}}\\\end{aligned}[/tex]

The value of [tex]\lambda[/tex] for transition from n = 6 to n = 2 is the least and therefore this transition corresponds to the shortest wavelength.

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Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Atomic structure

Keywords: Rydberg constant, wavelength, n1, n2, positive integers, transition, 2, 6, 3, 5, transition, Rh, spectral line, shortest wavelength.

Answer: The balanced chemical equation is written below.

Explanation:

Balanced chemical equation is defined as the equation in which total number of individual atoms on the reactant side will be equal to the total number of individual atoms on the product side. These equations follow law of conservation of mass.

The chemical equation for the reaction of lead (II) nitrate and potassium phosphate follows:

[tex]3Pb(NO_3)_2(aq.)+2K_3PO_4(aq.)\rightarrow Pb_3(PO_4)_2(s)+6KNO_3(aq.)[/tex]

By Stoichiometry of the reaction:

3 moles of aqueous lead (II) nitrate reacts with 2 moles of aqueous solution of potassium phosphate to produce 1 mole of solid lead (II) phosphate and 6 moles of aqueous solution of potassium nitrate.

Hence, the balanced chemical equation is written above.

The density of some unknown solid whose weight is 84.0 grams and volume is 30.0 cm3 is 2.8 g/mL.

Density may be defined as a type of physical property that significantly deals with the description of how much space an object or substance takes up with respect to the amount of matter in that object or substance.

In a more simple sense, it is characterized as the measurement of quantity or mass per unit of volume in a particular substance.

According to the question,

The mass of the unknown solid =  84.0 grams.

The volume of the unknown solid = 30.0 cm3.

Now, the formula for calculating the density is as follows:

                     = 84.0 g / 30.0 mL (1 cubic centimeter = 1 mL).

                     = 2.8 g/mL.

Therefore, the density of some unknown solid whose weight is 84.0 grams and volume is 30.0 cm3 is 2.8 g/mL.

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Answer:

The degree of rotation of racemic mixture will equal 0° 

Explanation:

Hello,

(-) isomer is in other words the Enantiomer of (+) isomer and as long as the statement indicates that (+)-isomer optical rotation is + 13.5°, the optical rotation of (-)-isomer will be the same value and degree but with the inverse sign which is -13.5°.

In such a way, the degree of rotation of the taken into account racemic mixture will equal 0° 

This is in this way due to the fact that the racemic mixture has equal amount of both enantiomers.

Best regards.

Final answer:

The atomic mass closest to carbon without calculations is 12.00 amu since carbon's average atomic mass is listed as 12.011 amu on the periodic table, and it mostly consists of carbon-12.

Explanation:

The atomic mass of an element like carbon is the weighted average of the masses of its naturally occurring isotopes. Carbon is predominantly composed of carbon-12, which has an atomic mass of exactly 12 amu (atomic mass units), as this isotope makes up about 98.90% of naturally occurring carbon. Because of this, the average atomic mass of carbon is close to 12 amu, but slightly higher due to the presence of the carbon-13 isotope. The periodic table lists carbon's atomic mass as 12.011 amu, making 12.00 amu the mass closest to carbon's atomic mass without doing any calculations.

The first step to answering this item, is to balance first the chemical reaction. This is shown below.

      Mg(s) + 2HCl (aq) --> MgCl₂(aq) + H₂(g)

HCl is multiplied by 2 to equalize the number of the hydrogen and chlorine.

The molar masses of magnesium and hydrogen gas are 24.3 g and 2 g, respectively. Using dimensional analysis and conversions, mass of hydrogen is calculated through the equation,

 Mass of H₂ =    (0.373 g Mg)(1 mol Mg/24.3 g Mg)(1 mol H₂/ 1 mol Mg)(2 g H₂/1 mol H₂)

             Mass of hydrogen = 0.031 g of hydrogen

Answer:

2,2,3-trimethyl-butane

Explanation:

Hello,

On the attached picture, you will find one isomer with chemical formula C₇H₁₆ which is 2,2,3-trimethyl-butane as it has the required three methyl brances on the parent chain, therefore, they must be arranged in the inner carbons otherwise, they will be considered as part of the parent chain.

Best regards.

Final answer:

The structure of the 1 isomer of C7H16 with three methyl branches on the parent chain can be represented as 2,2,3-trimethylbutane, which has a butane backbone with two methyl groups on the second carbon and one on the third.

Explanation:

The student asked to draw the structure of the 1 isomer of C7H16 that contains 3 methyl branches on the parent chain. For heptane (C7H16), one possible isomer with three methyl branches on the parent chain could be 2,2,3-trimethylbutane. In this structure, we have a four-carbon (butane) chain as the parent, with methyl groups attached to the second and third carbons (two on the second and one on the third).

Here's how you could write it out in steps:

To take the percent by mass of this element, we use the formula:

% mass = (mass of element / mass of ore) * 100%

% mass = (47.5 g / (660 kg * 1000 g / kg)) * 100*

% mass = 7.20 x 10^-3 %

Answer: The mass percent of element in the ore is 0.0072 %

Explanation:

To calculate the mass percentage of element in ore, we use the equation:

[tex]\text{Mass percent of element}=\frac{\text{Mass of element}}{\text{Mass of ore}}\times 100[/tex]

Mass of element = 47.5 g

Mass of ore = 660 kg = 660000 g    (Conversion factor:  1 kg = 1000 g)

Putting values in above equation, we get:

[tex]\text{Mass percent of element}=\frac{47.5g}{660000g}\times 100=0.0072\%[/tex]

Hence, the mass percent of element in the ore is 0.0072 %

Final answer:

To find out how many 0.05 mL drops of blood are in a 2 mL blood collection tube, divide the total volume by the volume of one drop. The calculation shows that there are 40 drops in a 2 mL tube.

Explanation:

To determine how many drops of blood are in a blood collection tube that holds 2 mL, we need to understand the relationship between the volume of the drops and the total volume that the tube can hold. Given that each drop of blood is 0.05 mL, we can calculate the number of drops in 2 mL by dividing the total volume by the volume of a single drop.

Here is the step-by-step calculation:

Determine the volume of one drop: 0.05 mL.

Determine the total volume of the collection tube: 2 mL.

Divide the total volume by the volume of one drop: 2 mL / 0.05 mL per drop.

Calculate the number of drops: 40 drops.

Answer:

6 electrons are in the third level if the atom.

The density of a metal given a mass of 5.23 g and a volume of 0.27 mL is calculated using the formula density = mass / volume, resulting in a density of 19.37 g/mL, with the final answer limited to four significant figures.

To identify the density of a metal given its mass and volume, you can use the formula for density, which is density = mass / volume. Given a 5.23 g sample of metal that occupies 0.27 mL, you first ensure the units are correct for density in g/mL. You then simply divide the mass by the volume.

So, density = 5.23 g / 0.27 mL = 19.37 g/mL.

This calculation gives us the density of the metal. Remember, when calculating density, it's important to ensure that your units are consistent, and for density, g/mL is a common unit. Additionally, when expressing your final answer, it matches the number of significant figures from the given data, in this case, being limited to four significant figures due to the precision of the volume measurement.

Answer : The correct option is, (d) He and Be

Explanation :

First we have to determine the electronic configuration of the following elements.

The electronic configuration of hydrogen (H) is:

[tex]1s^1[/tex]

The electronic configuration of carbon (C) is:

[tex]1s^22s^22p^2[/tex]

The electronic configuration of lithium (Li) is:

[tex]1s^22s^1[/tex]

The electronic configuration of helium (He) is:

[tex]1s^2[/tex]

The electronic configuration of beryllium (Be) is:

[tex]1s^22s^2[/tex]

From the electronic configuration of the elements we conclude that, the hydrogen element has '1' valence electron, carbon element has '4' valence electrons, lithium element has '1' valence electron, helium element has '2' valence electrons and beryllium element has '2' valence electrons.

Thus, the helium and beryllium are the elements that holds up to two electrons in their outermost shell.

Hence, the correct option is, (d) He and Be