Find the pH of the solution obtained when 0.027 L of 0.063 M benzylamine, C7H7NH2, is titrated to the equivalence point with 0.048 M hydrochloric acid. Kb for benzylamine is 4.7×10-10.

Answer:

5.61 e⁻³

Explanation:

Given that:

The barrier length = 0.681 nm = 6.81 × 10⁻¹⁰

The difference between the height of the barrier & the energy of the electron is;

[tex]V - E = 0.554 \ eV (1.6 \times 10^{-19} )[/tex]

= 8.864 × 10⁻²⁰ V

where;

m = 9.1 × 10⁻³¹ kg

The probability[tex]P = e^{-2 \ kd}[/tex]

[tex]k = 2 \pi \sqrt{\dfrac{2m (V-E)}{h^2} }[/tex]

[tex]k = 2 \pi \times \dfrac{\sqrt{2 \times 9.1 \times 10^{-31} \times 8.864 \times 10^{-20}}}{6.63 \times 10^{-34}}[/tex]

k = 3.806 × 10⁹

[tex]P = e^{-2 \ kd}[/tex]

[tex]P = e^{2 \times 3.806 \times 10^9 \times 6.81 \times 10^{-10}}[/tex]

P = 0.005606

P = 5.61 × 10⁻³

P = 5.61 e⁻³

Answer:

bottom right corner with arrows going up

Answer:

3.69 g

Explanation:

Given that:

The mass m = 325 g

The change in temperature ΔT = ( 1540 - 165)° C

= 1375 ° C

Heat capacity [tex]c_p[/tex] = 0.490 J/g°C

The amount of heat required:

q = mcΔT

q =  325 × 0.490 × 1375

q = 218968.75 J

q = 218.97 kJ

The equation for the reaction is expressed as:

[tex]C_2H_{2(g)} + 5O_{2(g)} \to 2CO_{2(g)} + H_2O_{(g)} \ \ \ \ \ \Delta H^o_{reaction} = -1544 \ kJ[/tex]

Then,

1 mole of the ethyne is equal to 26 g of ethyne required for 1544 kJ heat.

Thus, for 218.97 kJ, the amount of ethyne gas required will be:

[tex]= \dfrac{26 \ g}{1544 \ kJ} \times 218.97 \ kJ[/tex]

= 3.69 g

Explanation:

₇N = 1s² 2s² 2p³

Therefore,

Option C is correct ✔

Explanation:

Because of this, DNA and RNA can easily dissolve in water. ... Adding ethanol helps the Na+ and PO3- ions come together, because ions travel easier in ethanol than water. The supernate is removed and new ethanol is added in the second washing. This removes any residual salt that remained on the pelleted DNA.

Answer:

DNA is polar due to its highly charged phosphate backbone. Its polarity makes it water-soluble (water is polar) according to the principle "like dissolves like". ... This fact makes water a very good solvent for charged compounds like salts.

Your DNA's sugar phosphate backbone is charged. By adding salt, we help neutralize the DNA charge and make the molecule less hydrophilic, meaning it becomes less soluble in water. The salt also helps to remove proteins that are bound to the DNA and to keep the proteins dissolved in the water.

It is well known that Ethanol has a lower dielectric constant than water, making it to promote ionic bond formations between the Na+ (from the salt) and the PO3- (from the DNA backbone), further, causing the DNA to precipitate.

Explanation:

Ideally DNA needs to be precipitated with pellet and should not remain in supernatant. DNA is acidic in nature and therefore, needs optimum salt concentration in the buffer to be pelleted from a solution. At very low salt concentration or without salt DNA would remain in supernatant.

Answer: Cul2 + Br2 ->

Explanation:

Answer:

i believe the answer is a

Explanation:

Answer:

See the answers below

Explanation:

13.5 g of NH4Cl was dissolved in 315 mL of water.

Moles of NH4Cl present in the solution = mass/molar mass

Molar mass of NH4Cl = 54.49 g/mol

a) Moles of NH4Cl = 13.5/54.49

            = 0.25 mole

b) Molarity of solution = moles of solute/volume of solution

moles of NH4Cl = 0.25

volume of solution = 315 mL = 0.315 L

molarity = 0.25/0.315

             = 0.79 M

c) moles required = 0.0500 mole

molarity = 0.79 M

molarity = moles x volume

volume = molarity/moles

         = 0.79/0.0500

         = 15.8 L = 15,800 mL

One major characteristic they have in common is they are metals.

Answer:

protons = 26; neutrons = 30

Explanation:

protons = atomic number; neutrons = atomic mass – # of protons.

Answer:

0.0457 M

Explanation:

The reaction that takes place is:

First we calculate how many moles of acid reacted, using the HBr solution's concentration and volume:

Now we convert HBr moles to Ca(OH)₂ moles, using the stoichiometric ratio:

Finally we calculate the molarity of the Ca(OH)₂ solution, using the given volume and calculated moles:

Answer:

D. Upper right

Explanation:

The position the student should look for such element is in the upper right corner before the noble gases.

Specifically, the group of halogens will react vigorously with lithium.

Answer:

D. Upper right

Explanation:

I had the exact same question

Answer:

Heat the molecule

Explanation:

Since most bonds require energy to form, they also give off energy when they are broken. But before most bonds break, the molecule has to be heated. Then the atoms start to move, and when they move too much, the bond breaks. Molecules that require less energy to break than they give off when broken are called fuels.

Answer: Density means the compactness of an object

I hope this helps, and Happy Holidays! :)

Answer:

YOURE AMAZING THANK YOU THANK YOU THANK YOU

Explanation:

Answer:

87.5 %

Explanation:

Step 1: Given data

Step 2: Calculate the percent yield

When working with chemical reactions, we can determine the efficience in obtaining a product measuring the percent yield. The theoretical yield is the maximum amount of product that we could obtain according to the stoichiometry, whereas the real yield is the amount of product that we actually obtain when we carry out the process. We can calculate the percent yield usign the following expression.

%yield = real yield / theoretical yield × 100%

%yield = 105 kg / 120 kg × 100%

%yield = 87.5 %

Answer:

A) 0.801

Explanation:

The reaction that takes place is:

First we calculate the H₂SO₄ moles that reacted:

Now we convert H₂SO₄ moles to NaOH moles:

Finally we calculate the molarity of the NaOH solution:

So the answer is option A.

The molarity of the NaOH solution used in the neutralization reaction has been 0.801 [tex]\rm \times\;10^-^3[/tex] M. Thus, option A is correct.

The neutralization reaction has resulted in the formation of the salt and water on reacting an acid with a base. In the neutralization reaction, the strength of acid and base can be given as:

[tex]\rm 2\;NaOH\;+\;H_2SO_4\;\rightarrow\;Na_2SO_4\;+\;H_2O[/tex]

For the neutralization of 1 mole of sulfuric acid, 2 moles of NaOH has been required.

The moles of sulfuric acid can be given as:

Moles = Molarity × Volume

Given, the molarity of acid ([tex]\rm H_2SO_4[/tex]) = 0.355 M

Volume of acid = 28.2 ml = 0.0282 L

Volume of base (NaOH) = 25 ml = 0.025 L

Moles of [tex]\rm H_2SO_4[/tex] = 0.355 × 0.0282 mol

Moles of [tex]\rm H_2SO_4[/tex] = 10.011  mol.

Since, 1 mole [tex]\rm H_2SO_4[/tex] = 2 moles NaOH

10.011 moles [tex]\rm H_2SO_4[/tex] = 10.011 × 2 moles NaOH

10.011 moles [tex]\rm H_2SO_4[/tex] = 20.022 moles NaOH.

The neutralization of 0.355 M [tex]\rm H_2SO_4[/tex] requires 20.022 moles NaOH. The strength of the NaOH solution will be:

Molarity = [tex]\rm \dfrac{Moles}{Volume\;(L)}[/tex]

Molarity of NaOH = [tex]\rm \dfrac{20.022}{0.025}[/tex]

Molarity of NaOH = 0.801 [tex]\rm \times\;10^-^3[/tex] M.

The molarity of the NaOH solution used in the neutralization reaction has been 0.801 [tex]\rm \times\;10^-^3[/tex] M. Thus, option A is correct.

For more information about the neutralization reaction, refer to the link:

https://brainly.com/question/4612545

Answer:

The ability of an atom to accept an electron.

Explanation:

Electron affinity is measured by observing the energy change of a substance when an electron is added to it in its neutral gas form. For example, elements that are on the far right of the periodic table (excluding noble gases) are more likely to accept electrons rather than give them up. This is why Fluorine has the highest electron affinity of all atoms on the periodic table.

Answer:

Balanced Chemical Equation

CH4 + 4Cl2 → CCl4 + 4HCl

Explanation:

Brainliest please?

The observations of the tree's characteristics would be useful in determining its identity with a dichotomous key is its leaves are long and narrow. The correct option is B.

Observation is a process of recognizing and recording an event or fact that frequently involves measuring it with tools. Recognizing and recording an event, or fact frequently involves measuring with tools. Field notes are written observations made while participating in field observations or immediately afterward.

They are crucial for understanding phenomena that have been seen in the field. Field notes frequently take the form of scratch notes, diaries, and notebooks. In the scientific field, observation is a crucial step.

Therefore, the correct option is B. Its leaves are long and narrow.

To learn more about observation, refer to the link:

https://brainly.com/question/13196625

#SPJ6

Answer:

212 degrees Fahrenheit

Explanation:

When liquid water reaches a low enough temperature, it freezes and becomes a solid—ice. When solid water is exposed to enough heat, it will melt and return to a liquid. As that liquid water is further heated, it evaporates and becomes a gas—water vapor.

Answer:

The boiling point of gallium would be most similar to aluminum, and the boiling point of oxygen would be least similar to aluminum.

Explanation:

The atomic number of aluminum is 13, in the periodic table, magnesium lies in a similar period as Aluminum and Gallium is also present in a similar group. Thus, it can be expected that both magnesium and gallium exhibits similar boiling points with aluminum. However, gallium is a poor non-metal just like aluminum, while magnesium is a metal. Thus, it can be said that the boiling point of aluminum is more similar to gallium.

Now of the given elements, oxygen is a gas, thus, the boiling point of oxygen would be least similar to aluminum.

Answer:

Average atomic mass  = 57.79 amu

Percent contribution of Ni-60 = 26.45%

Percent contribution of Ni-5 =  73.55%

Explanation:

Given data:

Number of atoms of Ni-60 = 32

Number of atoms of Ni-57 = 89

Percent distribution of both isotopes = ?

Average atomic mass of sample = ?

Solution:

Percent contribution:

Total number of atoms = Ni-60 + Ni-57

Total number of atoms = 32 +89 = 121

Percent contribution of Ni-60 = 32/121×100

                                             =   26.45%

Percent contribution of Ni-57 = 89/121×100

                                             =  73.55%

Average atomic mass:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

Average atomic mass  = (26.45×60)+(73.55×57) /100

Average atomic mass =  1587 + 4192.35 / 100

Average atomic mass  = 5779.35 / 100

Average atomic mass  = 57.79 amu.

Answer:

Beta particles

Explanation:

A beta emission is said to occur when a neutron is converted into a proton. When a beta emission takes place, the daughter nucleus increases it's atomic number by 1. A neutrino is also produced.

Since the mass number remain the same but the daughter nucleus has it's atomic number increased by 1, then the particle is a beta particle.

Answer: D

Explanation: because the earth is slanted and at the north and south pole do not get that much sunlight so that makes it colder than most places on earth

The frequency of photon=6.03 x 10³³ /s

Radiation energy is absorbed by photons

The energy in one photon can be formulated as

[tex]\large{\boxed{\bold{E\:=\:h\:.\:f}}}[/tex]

Where

h = Planck's constant (6,626.10⁻³⁴ Js)

f = Frequency of electromagnetic waves

Energy of photon = 4 J

So the frequency :

[tex]\tt f=\dfrac{E}{h}\\\\f=\dfrac{4}{6.626.10^{-34}}\\\\f=6.03.10^{33}/s[/tex]

The density of metal = 4.5 g/ml, and the metal = Titanium

Density is a quantity derived from the mass and volume  

Density is the ratio of mass per unit volume  

Density formula:  

[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]

ρ = density  

m = mass  

v = volume  

mass of metal=27 g

volume = 6 ml

The density :

[tex]\tt \rho=\dfrac{27}{6}\\\\\rho=4.5~g/ml[/tex]

The metal with a density of 4.5 g/ml is Titanium

Answer:

A) Cl2 + 2NaI = 2NaCl + I2

Answer: The half life of the sample of silver-112 is 3.303 hours.

Explanation:

All radioactive decay processes undergoes first order reaction.

To calculate the rate constant for first order reaction, we use the integrated rate law equation for first order, which is:

[tex]k=\frac{2.303}{t}\log \frac{[A_o]}{[A]}[/tex]

where,

k = rate constant = ?

t = time taken = 1.52 hrs

[tex][A_o][/tex] = Initial concentration of reactant = 100 g

[A] = Concentration of reactant left after time 't' = [100 - 27.3] = 72.7 g

Putting values in above equation, we get:

[tex]k=\frac{2.303}{1.52hrs}\log \frac{100}{72.7}\\\\k= 0.2098hr^{-1}[/tex]

To calculate the half life period of first order reaction, we use the equation:

[tex]t_{1/2}=\frac{0.693}{k}[/tex]

where,

[tex]t_{1/2}[/tex] = half life period of first order reaction = ?

k = rate constant = [tex]0.2098hr^{-1}[/tex]

Putting values in above equation, we get:

[tex]t_{1/2}=\frac{0.693}{0.2098hr^{-1}}\\\\t_{1/2}=3.303hrs[/tex]

Hence, the half life of the sample of silver-112 is 3.303 hours.

Answer:

153.56g

Explanation:

Number of moles = mass/molar mass

To get the number of moles of the molecule, we divide the number of molecules contained by Avagadro's number, which is 6.02 × 10^23 molecules.

moles = 4.12 × 10^24 ÷ 6.02 × 10^23

number of moles = 0.684 × 10^(24-23)

number of moles = 0.684 × 10^(1)

number of moles = 6.84mol

If the molar mass of the molecule is 22.45 g/mol, the mass of the molecule can be calculated thus:

mass = moles × molar mass (MM)

mass = 6.84 × 22.45

mass = 153.558

mass = 153.56g