The heat of vaporization for benzaldehyde is 48.8 kJ/mol, and its normal boiling point is 451.0 K. Use this information to determine benzaldehyde’s vapor pressure (in torr) at 53.5°C. Report your answer to three significant digits.

Answer:

ethyl acetate layer

Explanation:

This question tests your knowledge of the principle of solvent extraction.

In solvent extraction, there is always an organic layer and an aqueous layer. The ethyl acetate is the organic layer while the sodium bicarbonate is the aqueous layer.

A brominated aromatic compound will be extracted into the organic layer (ethyl acetate layer).

Answer:

Creativity can help scientists by leading them to ask more questions about the natural world.

Explanation:

Beacause they use creativity to make up questions about the natural world.

Answer:

4.5 × 10⁻⁹

Explanation:

Step 1: Write the reaction for the solution of CaCO₃

CaCO₃(s) ⇄ Ca²⁺(aq) + CO₃²⁻(aq)

Step 2: Convert the solubility of CaCO₃ from g/L to mol/L

We will use the following conversion factors:

[tex]\frac{0.00067 gCaCO_3}{100mLSol} \times \frac{1molCaCO_3}{100.09gCaCO_3} \times \frac{1000mLSol}{1LSol} = 6.7 \times 10^{-5} M[/tex]

Step 3: Calculate the solubility product constant (Ksp)

To relate Ksp and the molar solubility (S), we need to make an ICE chart.

        CaCO₃(s) ⇄ Ca²⁺(aq) + CO₃²⁻(aq)

I                               0                0

C                            +S               +S

E                              S                 S

The solubility product constant is:

Ksp = [Ca²⁺].[CO₃²⁻] = S² = (6.7 × 10⁻⁵)² = 4.5 × 10⁻⁹

Answer:

1) 97.6%

2) No the purity is not acceptable because the standard is 99.5% purity.

3) Yes I will repeat the titration experiment to confirm my result.

Explanation:

Equation of the reaction;

C7H6O2(aq) + NaOH(aq) ---------> C7H5ONa(aq) + H2O(aq)

From the information provided;

Number of moles of NaOH reacted = concentration × volume = 20.15/1000 × 0.500 = 0.01 moles

From the reaction equation;

1 mole of C7H6O2 reacts with 1 mole of NaOH

Hence 0.01 moles of C7H6O2 will react with 0.01 moles of NaOH

Mass of C7H6O2 reacted = number of moles of C7H6O2 × molar mass of C7H6O2

Molar mass of C7H6O2 = 122.12 g/mol

Mass of C7H6O2 reacted = 0.01 moles × 122.12 g/mol = 1.22 g

Percentage by mass of pure C7H6O2 in the impure sample = 1.22/1.250 × 100 = 97.6 %

Answer:

The wavelength of light (in nm) of the spectral line of Hydrogen where an electron falls from the 6th Bohr orbit to the 3rd Bohr orbit is 1090nm

Explanation:

We know that , the wavelength of the light is calculated by Rydberg's formula-

[tex]\frac{1}{\pi} =R^2(\frac{1}{n^2_1} -\frac{1}{n^2_2})[/tex]  [tex][n_2>n_1][/tex]

Here , R = Rydberg's constant [tex](1.097\times 10^7 m^-^1)[/tex]

          Z = atomic number (for hydrogen , Z= 1)

     [tex]n_2 =6 , n_1=3[/tex]

[tex]\pi =[/tex] wavelength of light

Now , putting the values in the Rydberg's formula ,

  [tex]\frac{1}{\pi} =1.097\times10^7m^-^1(\frac{1}{3^2} -\frac{1}{6^2} )[/tex]

     =[tex]1.097\times 10^7m^-^1 (\frac{4-1}{36} )[/tex]

    =[tex]1.097\times 10^7m^-^1(\frac{3}{36} )[/tex]

      =[tex]1.097\times 10^7m^-^1(\frac{1}{12} )[/tex]

  [tex]\frac{1}{\pi}[/tex]   = [tex]0.0914167\times 10^7m^-^1[/tex]

[tex]\pi=\frac{1}{0.0914167\times10^7m^-^1}[/tex]

[tex]\pi=10.9389\times10^-^7\\\pi=1093.89\times10^-^9m[/tex]

  =1090nm

Hence , the wavelength of the light is 1090nm,, that is option D is correct.

Answer:

I want to say option C: four atoms of oxygen. Sorry if I'm wrong

Answer:

Explanation:

Al(s) + 3/2 Br₂(l) = AlBr₃(s)

K = [  AlBr₃] / [ Al] [  Br₂]³/²

K² =  [  AlBr₃]² / [  Al ] ² [ Br₂]³

2 AlBr₃ = 2 Al(s) + 3 Br₂(l) =

K₁ =  [  Al ] ² [ Br₂]³ /  [  AlBr₃]²

K₁ =  ( 1 / K² ) = K⁻²

2 ) 2 Al(s) + 3 Br₂(l) = 2 AlBr₃(s)

K₂ = [ AlBr₃ ]² / [  Al ]² [  Br₂ ]³

K₂ = K²

3 )

AlBr₃(s) =   Al(s) + 3/2 Br₂(l)

K₃  = [ Al ] [ Br₂ ] ³/² / [ AlBr₃ ]

=  ( 1 / K ) = K⁻¹

Answer:

–23000 Calories.

NOTE : The negative sign indicates that heat has been loss to the student back.

Explanation:

The following data were obtained from the question:

Mass (M) of water = 575 g

Initial temperature (T1) = 80 °C

Final temperature (T2) = 40 °C

Heat (Q) transferred =.?

Next, we shall determine the change in temperature (ΔT).

This is illustrated below:

Initial temperature (T1) = 80 °C

Final temperature (T2) = 40 °C

Change in temperature (ΔT) =?

Change in temperature (ΔT) = T2 – T1

Change in temperature (ΔT) = 40 – 80

Change in temperature (ΔT) = –40°C

Finally, we shall determine the heat transferred. This can be obtained as follow:

Mass (M) of water = 575 g

Change in temperature (ΔT) = –40°C

Specific heat capacity (C) of water = 1 Cal/g°C

Heat (Q) transferred =.?

Q = MCΔT

Q = 575 × 1 × –40

Q = –23000 Calories

NOTE : The negative sign indicates that heat has been loss to the student back.

Answer:

Oxygen is used up

Explanation:

Have an amazing day! And here is the attachment If you don't believe me. Brainliest would be nice.

Answer:

[H+] = 7.576x10⁻⁴M

pH = 3.12

Explanation:

Based on the equilibrium of the nicotinic acid in water:

HC6H4NO2(aq) + H2O(l) ⇄ C6H4NO2-(aq) + H3O+(aq)

Ka = [C6H4NO2-] [H3O+] / [HC6H4NO2]

As both C6H4NO2-(aq) and H3O+(aq) comes from the same equilibrium, we can approximate their concentration as X and replace:

Ka = [C6H4NO2-] [H3O+] / [HC6H4NO2]

1.4x10⁻⁵ = [X] [X] / [0.041M]

5.47x10⁻⁷ = X²

And as pH is defined as -log [H⁺]

Answer:

1.23 g

Explanation:

Given that the mass of barium phosphate formed= 3.54 g

Molar mass of Ba3 (PO4)2 = 602 g/moles

Number of moles of Ba3 (PO4)2= 3.54g/602 g/moles = 0.0059 moles

Since 1 mole of BaCl2 forms 1 mole of Ba3 (PO4)2

Hence, 0.0059 moles of BaCl2 yields 0.0059 moles of Ba3 (PO4)2

Hence mass of BaCl2 reacted= mass × molar mass= 1.23 g

Calcium (Ca) is in group 2 and period 4 on the periodic table be because Calcium has 2 valence electrons and 4 electron shell. Thus, calcium is a metal like all other group 2 element.

The correct answer to the question is Option C. Calcium, like all group 2 elements, is reactive and a solid at room temperature.

Calcium is a group 2 element majorly because it has 2 valence electrons. It is also in period 4 because it has 4 electron shells.

Being a group 2 element, calcium is a solid at room temperature and also reactive. All elements in the group 2 are metals.

There are other elements in period 4 which are not solid. For example krypton is an element in period 4 and it is a gas and not reactive.

From the above information, we can conclude that the correct answer to the question is:

Option C. Calcium, like all group 2 elements, is reactive and a solid at room temperature.

See attached image

Learn more: https://brainly.com/question/5979466

Answer:

valence electrons

Explanation:

it is outermost shell of electrons

The three dots in the Lewis dot diagram for boron indicates that it has three valence electrons.

The three dots in the Lewis dot diagram for boron indicates that it

The three dots in the Lewis dot diagram for boron indicates that it has three valence electrons.

You can learn more about the Lewis dot structure here: https://brainly.com/question/20300458

Answer:

57.9 grams .

Explanation:

Ca₃(PO₄)₂ + 3H₂SO₄   → 3CaSO₄ + 2H₃PO₄

1 mole         3 moles                              2 moles

149 g of Ca₃(PO₄)₂ = 149 / 310 = .48 moles

86.9 g of H₂SO₄ = 86.9 / 98 = .8867 moles

Here H₂SO₄  is the limiting reagent .

.8867 / 3 = .2955

.2955 moles of Ca₃(PO₄)₂ reacts with  .8867 mole of H₂SO₄  to give

2 x .2955 moles of H₃PO₄

H₃PO₄ produced = 2 x .2955 moles

= .591 moles

= .591 x 98 = 57.9 grams .

Answer:

Endothermic reaction

Explanation:

Endothermic reactions are defined as the type of chemical reaction in which the system absorbs the energy from the surroundings and the temperature of the surrounding decreases while in Exothermic reactions, heat is released by the system to the surroundings and it makes the surrounding warm.

The given example is an "endothermic reaction" because the reaction between NH4Cl and water is making the surrounding cool (cold pack) due to the release of heat.

Hence, the correct answer is "endothermic reaction".

Order, sensitivity or response to the environment, reproduction, growth and development, regulation, homeostasis, and energy processing.

Answer:

Cell wall, chloroplast, and vacuoles

Explanation:

Answer:

[tex]m_{Ag}=2,265.9g[/tex]

Explanation:

Hello!

In this case, since the definition of entropy in a random mixture is:

[tex]\Delta S=-n_TR\Sigma[x_i*ln(x_i)][/tex]

For this silver-gold mixture we write:

[tex]\Delta S=-(n_{Au}+n_{Ag})R\Sigma[\frac{n_{Au}}{n_{Au}+n_{Ag}} *ln(\frac{n_{Au}}{n_{Au}+n_{Ag}} )+\frac{n_{Ag}}{n_{Au}+n_{Ag}} *ln(\frac{n_{Ag}}{n_{Au}+n_{Ag}} )][/tex]

By knowing the moles of gold:

[tex]n_{Au}=100g*\frac{1mol}{197g} =0.508mol[/tex]

It is possible to write the aforementioned formula in terms of the variable [tex]x[/tex] representing the moles of silver:

[tex]20\frac{J}{mol}=-(0.508+x)8.314\frac{J}{mol*K} \Sigma[\frac{0.508}{0.508+x} *ln(\frac{0.508}{0.508+x} )+\frac{x}{0.508+x} *ln(\frac{x}{0.508+x} )][/tex]

Which can be solved via Newton-Raphson or a solver software, in this case, I will provide you the answer:

[tex]x=n_{Ag}=21.0molAg[/tex]

So the mass is:

[tex]m_{Ag}=21.0mol*\frac{107.9g}{1mol}\\ \\m_{Ag}=2,265.9g[/tex]

Best regards!

Answer:

30 neutrons

Explanation:

Since the mass of the iron nuclide is 56 , there must be 56−26=30 neutrons, 30 massive, neutral particles in this iron nucleus.

Answer:

C

Explanation:

It will be the same. That's what moving down a column means. The properties are going to be quite similar.

Answer:

A

Explanation:

B- is dna related

C i dunno

and d is about protein so that leaves A

Answer:

C, Movement

Explanation:

Answer:

One mole of Al weighs 27g.

2.5 moles of Al weigh 67.5g.

Answer:

1.52g NaHCO3 were in the original mixture.

Mass percent: 64.1%

Explanation:

When NaHCO3 heats it descomposition occurs as follows:

2 NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g).

The loss in mass is because of the evaporization of CO2 and H2O. As both are in the same porportion, its molar mass is the sum of both compounds (44g/mol + 18g/mol = 62g/mol)

Loss in mass: 74.80g - 74.24g = 0.56g.

In moles:

0.56g * (1mol / 62g) = 0.00903 moles of gas.

As 1 mole of the gases comes from 2 moles of NaHCO3:

Moles NaHCO3:

0.00903 moles of gas * (2 moles NaHCO3 / 1 mole gas) = 0.018 moles NaHCO3.

In grams (Molar mass NaHCO3: 84g/mol):

0.018 moles NaHCO3 * (84g / mol) = 1.52g NaHCO3 were in the original mixture.

The mass of the mixture was:

74.80g - 72.428g = 2.372g

That means mass percent of NaHCO3 is:

(1.52g /  2.372g) * 100 =  64.1%

Answer:

The desert should be divided into different types based on its properties. The organisms living in specific type of desert should be named accordingly.

Explanation:

There are usually five major types of desert in the world. Tropical, rainy, semi arid desert, coastal desert and dry desert. There are many different types of organisms living in these deserts. The biodiversity has made it difficult for the humans to analyse and identify the millions of different types. The best way is to organize and name the organisms that live in specific types of deserts.

The question is incomplete, the complete question is:

This is the chemical formula for cassiterite (tin ore): SnO2 A geochemist has determined by measurements that there are 13. moles of tin in a sample of cassiterite. How many moles of oxygen are in the sample? Round your answer to 2 significant digits.

Answer:

Explanation:

In SnO2, there are two moles of oxygen for each mole of tin.

Hence, if there are 13 moles of tin, then we should have 13 * 2 moles of oxygen. This gives us 26 moles of oxygen.

Hence there are 26 moles of oxygen.

Answer:

The mass of Ca²⁺ present in the water sample =  13.23 mg/L.

The mass for the Mg²⁺ in the water sample =  25.06 mg/L.

Explanation:

We are given the following set of values which are going to aid in solving this particular question/problem. Thus, the parameters or data or information is given below:

First part:

Total volume of the water sample =  100.00-mL water sample, volume of the EDTA solution = 10.87 mL, the concentration of the EDTA solution = 0.0125 M, the adjusted pH of the water sample with  = 10.

Second part:

Total volume of the water sample =  100.00-mL water sample, volume of the EDTA solution = 2.63 mL and the adjusted pH of the water sample with  = 12.

Thus, the first thing to do now is to determine the number of moles of the EDTA solution in Ca²⁺ titration which is; 0.0125 x 0.00263 = 3.30 x 10⁻⁵ moles.

The mass of Ca²⁺ present in the water sample = [3.30 x 10⁻⁵ moles × 40.08 ] ÷ 100 mL. =  13.23 mg/L

In 100mL, the number of moles of Mg²⁺ = (total number of moles of EDTA solution used ) - ( number of moles of the EDTA solution in Ca²⁺ titration).

Also, The number of moles of Mg²⁺ = ( 0.0125  x 0.01087) - (3.30 x 10⁻⁵ moles.) =  1.031 x 10⁻⁴ moles.

The mass for the Mg²⁺ in the water sample =  1.031 x 10⁻⁴ moles  x  24.305/0.1 = 25.06 mg/L.