The pKb values for the dibasic base B are pKb1=2.10 and pKb2=7.54. Calculate the pH at each of the points in the titration of 50.0 mL of a 0.60 M B(aq) solution with 0.60 M HCl(aq).

Answer:

Ionic bond, also called electrovalent bond, type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound. Such a bond forms when the valence (outermost) electrons of one atom are transferred permanently to another atom.

Explanation: i took the same test

Answer:

it forms where a metal element and a non metal element react together to form a now compound

Answer:

35.1% is percent yield

Explanation:

Full question: Assume no volume change.  If you formed 0.0910 atm of gas, what is the percent yield?

The reaction that is occurring is:

Ni + 3HBr → NiBr₃ + 3/2H₂(g)

First, we will determine moles of Ni and HBr to determine limiting reactant and theoretical yield

Using ideal gas law, we can determine the moles of hydrogen formed. Thus, we can find percent yield:

Moles Ni (Molar mass: 58.69g/mol):

1.02g * (1mol / 58.69g) = 0.01738moles Ni

Moles HBr:

0.750L * (0.112mol/L) = 0.084 moles of HBr.

For a complete reaction of the 0.084 moles of HBr you need:

0.084mol HBr * (1 mole Ni / 3 moles HBr) = 0.028 moles of Ni.

As there are just 0.01738 moles of Ni, the Ni is limiting reactant. Assuming a theoretical yield, moles of H₂ produced are:

0.01738moles Ni * (3/2 H₂ / 1 mol Ni) = 0.02607 moles H₂

Now, moles of H₂ produced are:

PV = nRT

PV/RT = n

Where P is pressure (0.0910atm)

V is volume (2.50L)

R is gas constant (0.082atmL/molK)

T is absolute temperature in Kelvin (30°C + 273.15 = 303.15K)

And n are moles

PV/RT = n

0.0910atm*2.50L/0.082atmL/molK*303.15K = n

0.00915 moles = n

And percent yield (Produced moles / Theoretical moles * 100) is:

0.00915 moles / 0.02607moles =

Answer:

acceleration = force/mass

                 = (68.6+mg)/7

                 = 19.6 m/s²

Explanation:

9.8 m/s² is the acceleration acting on 7 kg mass if force of 68.6 N  is used to move it towards earth.

Force is defined as a cause which is capable of changing the motion of an object. It can cause an object which has mass to change it's velocity. It is also simply a push or a pull . It has both magnitude as well as direction.Hence, it is a vector quantity.

It has SI units of Newton and is represented by'F'.Newton's second law states that force which acts on an object is equal to momentum which changes with time. If mass of object is constant, acceleration is directly proportional to net force acting on an object.

The concepts which related to force are thrust and torque .Thrust increases the velocity of an object and torque produces change in rotational speed of an object.

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Answer:

the answer to this question is c 140

Answer:

Heterogeneous mixture

Explanation:

Soil is composed of small pieces of a variety of materials, so it is a heterogeneous mixture.

Answer:

Explanation:

In order to find out the mass of KOH to be used we use the formula

where

m is the mass

c is the concentration in mol/dm³

M is the molar mass

v is the volume in dm³

From the question

c = 2.8 M

v = 700 mL = 0.7 dm³

Mr( K) = 39 , Mr(O) = 16 , Mr(H) = 1

we have

Molar mass of KOH = 39 + 16 + 1

= 56 g/mol

So we have

m = 2.8 × 56 × 0.7

We have the final answer as

Hope this helps you

Answer:

CaCl₂ (aq) + 2NaOH (aq) —> Ca(OH)₂ (s) + 2NaCl (aq)

Explanation:

The equation for the reaction is given below:

CaCl₂ (aq) + NaOH (aq) —> Ca(OH)₂ (s) + NaCl (aq)

The above equation can be balance by as follow:

CaCl₂ (aq) + NaOH (aq) —> Ca(OH)₂ (s) + NaCl (aq)

There are 2 atoms of Cl on the left side and 1 atom on the right side. It can be balance by putting 2 in front NaCl as shown below:

CaCl₂ (aq) + NaOH (aq) —> Ca(OH)₂ (s) + 2NaCl (aq)

There are 2 atoms of Na on the right side and 1 atom on the left side. It can be balance by putting 2 in front of NaOH as shown below:

CaCl₂ (aq) + 2NaOH (aq) —> Ca(OH)₂ (s) + 2NaCl (aq)

Now, the equation is balanced.

Answer:

Protons,electrons,and neutrons make up matter

Explanation:

i studied this so hope it helps

Answer:

Molecular Formula Fe2O12S3·5H2O

IUPAC Name iron(3+);tri sulfate;pentahydrate

Explanation:

Answer:

trees

Explanation:

we plant trees hindi sure kung tama to hihi

Answer:

1 Faraday

Explanation:

This question seeks to test proper understanding of Faraday's second law of electrolysis which states when the same quantity electricity passes through a solution of different electrolytes, the mass of the substance deposited is directly proportional to there chemical equivalence.

This law hints at the charges of ions being the chemical equivalence and also been represented as the unit for the quantity of electricity in faraday, F. Hence, a metal with the charge of 1+ can be displaced by 1F (which is equal to 96, 500 coloumbs). This charge also represents one molecule of electron, thus 1 faraday corresponds to one mole of electrons.

NOTE: It should be noted that a metal with the charge of 2+ can be displaced by 2F and so on.

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

volume = final volume of water - initial volume of water

volume = 60 - 25 = 35 mL

From the question we have

[tex]density = \frac{140}{35} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

7.5%

Explanation:

I just know it's that

Answer:

Proton or electron. I think, not sure.

Explanation:

A proton and an electron have an equal amount but an opposite type of charge. Thus, if an atom contains equal numbers of protons and electrons, the atom is described as being electrically neutral.

eletrons I'm pretty sure

Answer:

Metamorphism is the change of minerals or geologic texture (distinct arrangement of minerals) in pre-existing rocks (protoliths), without the protolith melting into liquid magma (a solid-state change). The change occurs primarily due to heat, pressure, and the introduction of chemically active fluids.

Explanation:

i hope this helps :)

The average atomic mass is given by the individual atomic masses of the isotope of the element and its percentage. The average atomic mass of the isotopic mixture is 159.8 g/mole.

Isotopes are atoms of the same element that have the same number of protons in their nucleus but have a different number of neutrons that alters their atomic masses. The relative abundance of the isotope of the element affects the average atomic mass of the mixture.

The formula for average atomic mass for the mixture of isotopes is given as:

Average atomic mass = ∑ (mass × abundance)

Given,

Abundance of isotope 1 = 22.00 %

Mass of isotope 1 = 159.3 g/mole

Abundance of isotope 2 = 78.00 %

Mass of isotope 2 = 161.2g/mole

Substituting values in the formula of average atomic mass as:

Average atomic mass = isotope 1 (mass × abundance) + isotope 2 (mass × abundance)

= (0.22) × (159.3) + (0.78) × (161.2)

= 34.046 + 125.736

= 159.8 g/mole

Therefore, the average atomic mass of the mixture of the two isotopes is 159.8 g/mole.

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Answer:

ΔG° = -1.45 × 10⁵ J

Explanation:

Step 1: Given data

Step 2: Calculate the standard Gibbs free energy change (ΔG°)

We will use the following expression.

ΔG° = -n × F × E°cell

ΔG° = -1 mol e⁻ × 96,485 C/mol e⁻ × 1.50 V

ΔG° = -1.45 × 10⁵ J

By apply Gibbs's free energy, the value of delta G is equal to -144727.5 Joules.

Given the following data:

To determine the value of delta G, we would apply Gibbs's free energy:

Mathematically, Gibbs's free energy is given by the formula:

[tex]\Delta G^\circ = -nFE^{ \circ}_{cell}[/tex]

Where:

Substituting the given parameters into the formula, we have;

[tex]\Delta G^\circ = -1 \times 96485 \times 1.50[/tex]

[tex]\Delta G^\circ = -144727.5[/tex]

Delta G = -144727.5 Joules

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Answer:

u measure how much power it has

Explanation:

for example u can power a light bulb woth it if u can it was 100eg energy

Answer:

SBr2

Electron geometry-tetrahedral; molecular geometry-trigonal pyramidal

PI4+

Electron geometry-tetrahedral; moleculargeometry-tetrahedralr

IBr2

Electron geometry - tetrahedral ; molecular shape - bent

Explanation:

We have to carefully consider the issues in question 2.

First of all, the compound SiF4 is an AX4 molecule so both it's electron domain geometry and molecular geometry are tetrahedral. The molecule has no lone pairs.

For SeF4, the compound is a molecule of the type AX4E, its molecular geometry is trigonal bipyramid but its molecular geometry is see-saw because of the presence of a lone pair of electrons on the central atom, selenium.

For XeF4, the electron domain geometry is octahedral but its molecular geometry is square planar. The molecule is of the type AX4E2 and the two lone pairs are positioned above and below the plane of the square.

Answer:

It's called Evaporation.

Answer:

Long term condition of the atmosphere

Explanation:

I think this is right.

I hope this helps! (✿◕‿◕✿)

Answer:

Pb, Cr, Fe

Explanation:

The metals that can react with hydrochloric acid are; Sn, Cr and Ni.

The electrochemical series shows the reactivity of elements. An element can only replace another element in solution when that element is higher in the electrochemical series.

The metals that can replace hydrogen in a solution of hydrochloric acid must be metals that are above hydrogen in the electrochemical series. These metals are; Sn, Cr and Ni. Hg is a noble metal hence it does not replace hydrogen in an acid solution.

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Answer:

[tex]T_f=25.0\°C[/tex]

Explanation:

Hello.

In this case, considering that the sample of hot copper is submerged into the water and the container is isolated, the heat lost by the copper is gained by the water so we can write:

[tex]Q_{Cu}=-Q_w[/tex]

In terms of mass, specific heat and temperature we write:

[tex]m_{Cu}C_{Cu}(T_f-T_{Cu})=-m_wC_w(T_f-T_w)[/tex]

Whereas the final temperature is the same for both copper and water because they are in contact until thermal equilibrium is reached. In such a way, the required maximum temperature no more than the equilibrium temperature and is computed as shown below:

[tex]T_f=\frac{m_{Cu}C_{Cu}T_{Cu}+m_wC_wT_w}{m_{Cu}C_{Cu}+m_wC_w}[/tex]

Thus, plugging the given data in the formula, we obtain:

[tex]T_f=\frac{10.3g*0.385\frac{J}{g\°C}*100\°C +47.0g*4.184\frac{J}{g\°C}*23.5\°C }{10.3g*0.385\frac{J}{g\°C}+47.0g*4.184\frac{J}{g\°C}}\\\\T_f=25.0\°C[/tex]

Which is a small change considering the initial one, because the mass of water is greater than the mass of copper as well as for the specific heats.

Best regards!

The maximum temperature of the water in the insulated container after the copper metal is added is 25 °C

From the question given above above, the following data were obtained:

Mass of water (Mᵥᵥ) = 47 g

Temperature of water (Tᵥᵥ) = 23.5°C

Specific heat capacity of water (Cᵥᵥ) = 4.184 J/gºC

Mass of copper (M꜀) = 10.3 g

Temperature of copper (M꜀) = 100 °C

Specific heat capacity of copper (C꜀) = 0.385 J/gºC

The equilibrium temperature of the mixture can be obtained as follow:

Heat loss by copper = Heat gained by water

Q꜀ = Qᵥᵥ

M꜀C꜀(M꜀ – Tₑ) = MᵥᵥCᵥᵥ(Tₑ– Mᵥᵥ)

10.3 × 0.385 (100 – Tₑ) = 47 × 4.184 (Tₑ – 23.5)

3.9655 (100 – Tₑ) = 196.648 (Tₑ – 23.5)

Clear bracket

396.55 – 3.9655Tₑ = 196.648Tₑ – 4621.228

Collect like terms

396.55 + 4621.228 = 196.648Tₑ + 3.9655Tₑ

5017.778 = 200.6135Tₑ

Divide both side by 200.6135

Tₑ = 5017.778 / 200.613

Thus, the equilibrium temperature of the mixture is 25 °C. Therefore, the maximum temperature of the water in the insulated container is 25 °C

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Answer: The particles are moving fast but close together.

Answer:

its in the explanation.

Explanation:

1.In liquids, particles are quite close together and move with random motion throughout the container. Particles move rapidly in all directions but collide with each other more frequently than in gases due to shorter distances between particles.

2.It assumes the shape of the part of the container which it occupies particles can move/slide past one another.

Hope this helps. :)

Answer:

10.801 amu

Explanation:

From the question given above, the following data were obtained:

Isotope A (¹⁰B):

Mass of A = 10

Abundance (A%) = 19.9%

Isotope B (¹¹B):

Mass of B = 11

Abundance (B%) = 80.1%

Atomic mass of Boron =?

The atomic mass of boron can be obtained as illustrated below:

Atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100]

= [(10 × 19.9)/100] + [(11 × 80.1)/100]

= 1.99 + 8.811

= 10.801 amu

Thus, the atomic mass of boron is 10.801 amu

The atomic mass of boron with natural abundance of 19.9% of 10 B and 80.1%  of 11 B is 10.801 amu

Boron has 2 isotopes.

First isotopes

mass = 10

% abundance = 19.9%

Second Isotopes

mass = 11

% abundance = 80.1%

Therefore,

Atomic mass = (19.9% of 10) + (80.1% of 11)

Atomic mass = (19.9 / 100 × 10) + (80.1 / 100 × 11)

Atomic mass = 199 / 100 + 881.1 / 100

Atomic mass = 1.99 + 8.811

Atomic mass = 10.801

Atomic mass = 10.801 amu

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Answer:

The noble gases (Group 18) are located in the far right of the periodic table and were previously referred to as the "inert gases" due to the fact that their filled valence shells (octets) make them extremely nonreactive. The noble gases were characterized relatively late compared to other element groups.

The History

The first person to discover the noble gases was Henry Cavendish in the late 180th century. Cavendish distinguished these elements by chemically removing all oxygen and nitrogen from a container of air. The nitrogen was oxidized to  NO2  by electric discharges and absorbed by a sodium hydroxide solution. The remaining oxygen was then removed from the mixture with an absorber. The experiment revealed that 1/120 of the gas volume remained un-reacted in the receptacle. The second person to isolate, but not typify, them was William Francis (1855-1925). Francis noted the formation of gas while dissolving uranium minerals in acid.

Argon

In 1894, John William Strutt discovered that chemically-obtained pure nitrogen was less dense than the nitrogen isolated from air samples. From this breakthrough, he concluded that another, unknown gas was present in the air. With the aid of William Ramsay, Strutt managed to replicate and modify Cavendish's experiment to better understand the inert component of air in his original experiment. The researchers' procedure differed from the Cavendish procedure: they removed the oxygen by reacting it with copper, and removed the nitrogen in a reaction with magnesium. The remaining gas was properly characterized and the new element was named "argon," which originates from the Greek word for "inert."

Helium

Helium was first discovered in 1868, manifesting itself in the solar spectrum as a bright yellow line with a wavelength of 587.49 nanometers. This discovery was made by Pierre Jansen. Jansen initially assumed it was a sodium line. However, later studies by Sir William Ramsay (who isolated helium on Earth by treating a variety of rare elements with acids) confirmed that the bright yellow line from his experiment matched up with that in the spectrum of the sun. From this, British physicist William Crookes identified the element as helium.

Neon, Krypton, Xenon

These three noble gases were discovered by Morris W. Travers and Sir William Ramsay in 1898. Ramsay discovered neon by chilling a sample of the air to a liquid phase, warming the liquid, and capturing the gases as they boiled off. Krypton and xenon were also discovered through this process.

Radon

In 1900, while studying the decay chain of radium, Friedrich Earns Dorn discovered the last gas in Group 18: radon. In his experiments, Dorn noticed that radium compounds emanated radioactive gas. This gas was originally named niton after the Latin word for shining, "nitens". In 1923, the International Committee for Chemical Elements and International Union of Pure Applied Chemistry (IUPAC) decided to name the element radon. All isotopes of radon are radioactive. Radon-222 has the longest half-life at less than 4 days, and is an alpha-decay product of Radium-226 (part of the U-238 to Pb-206 radioactive decay chain).

The Electron Configurations for Noble Gases

Helium 1s2

Neon [He] 2s2 2p6

Argon [Ne] 3s2 3p6

Krypton [Ar] 3d10 4s2 4p6

Xenon [Kr] 4d10 5s2 5p6

Radon [Xe] 4f14 5d10 6s2 6p

Explanation: