In nature, oxygen has three common isotopes. The atomic masses and relative abundances of these isotopes are given in the table below. Isotope Atomic Mass (amu) Relative Abundance O-16 15.995 99.759% O-17 16.995 0.037% O-18 17.999 0.204% Calculate the average atomic mass of oxygen. Show all of your calculations below.

Answer: b. HSO4-

Explanation:

H2SO4 (sulfuric acid) will donate a hydrogen ion in solution to form H3O+(hydronium). The remaining HSO4- would be the conjugate base of this dissociation.

A conjugate base contains one less H atom and one more - charge than the acid that formed it.

A conjugate acid contains one more H atom and one more + charge than the base that formed it.

Answer: E = - 19.611×[tex]10^{-18}[/tex] J

Explanation: The lowest possible energy can be calculated using the formula:

[tex]E_{n} = - Z^{2}.\frac{k}{n^{2}}[/tex]

where:

Z is atomic number of the atom;

k is a constant which contains other constants and is 2.179×[tex]10^{-18}[/tex] J

n is a layer;

For the lowest possible, n=1.

Atom of Lithium has atomic number of Z=3

Substituing:

[tex]E_{1} = - 3^{2}.\frac{2.179.10^{-18}}{1}[/tex]

[tex]E_{1} =[/tex] [tex]-19.611.10^{-18}[/tex] J

The energy for the electron in the [tex]Li^{+2}[/tex] ion is - 19.611 joules

The lowest possible energy, in Joules, for the electron in the [tex]Li^{2+}[/tex] ion is equal to [tex]1.96\times 10^{-17}\; Joules[/tex]

To determine the lowest possible energy, in Joules, for the electron in the [tex]Li^{2+}[/tex] ion, we would use the Bohr model:

Mathematically, Bohr's model is given by the equation:

[tex]Energy = -Z^2 \frac{k}{n^2}[/tex]

Where:

We know that the atomic number of lithium (Li) is equal to 3.

Also, at the lowest possible energy, n = 1.

Rydberg constant = [tex]2.179 \times 10^{-18}[/tex]

Substituting the parameters into the equation, we have;

[tex]E_1 = -3^2 \times \frac{2.179 \times 10^{-18}}{1^2} \\\\E_1 =9 \times 2.179 \times 10^{-18}\\\\E_1 =1.96\times 10^{-17}\; Joules[/tex]

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Answer:

11445.8years

Explanation:

Half-life of carbon-14 = 5720 years

First we have to calculate the rate constant, we use the formula :

Answer:

Citra should make it equal to the length of the rod.

Explanation:

A basic permanent wrap method is a 9 section wrap method in which all the base sections are horizontal, having same length and width of the rod

Basic permanent wrap method causes a uniform curl from the scalp to the end of the hair.

In permanent wrap method, paneling the hair equal to the length will make the will give the same size as the rod.

The length of the rod determines the size of the curl.

Once Holly's hair is divided into panel and make it as wide as the length of the rod, it will curl in the same size as the rod lengths and the hair will perm well.

Answer:

b

Explanation:

The reaction that is not a displacement reaction from all the options is [tex]C_6H_6_{(l)} + Cl_{2(g)} --> C_6H_5Cl_{(l)} + HCl_{(g)}[/tex]

In a displacement reaction, a part of one of the reactants is replaced by another reactant. In single displacement reactions, one of the reactants completely displaces and replaces part of another reactant. In double displacement reaction, cations and anions in the reactants switch partners to form products.

Options a, c, d, and e involves the displacement of a part of one of the reactants by another reactant while option b does not.

Correct option = b.

The reaction given in Option A is not a displacement reaction. In Displacement reaction functional group of one reactant is replaced by the functional group of the another reactant.

Displacement reaction:

In this reaction functional group of one reactant is replaced by the functional group of the another reactant.

[tex]\bold { Zn(s) + FeCl_2(aq) \rightarrow ZnCl_2(aq) + Fe(s).}[/tex]

In the above reaction Zinc does not any functional group to exchange with iron chloride.

Therefore, the reaction given in Option A is not a displacement reaction.

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Answer:

1.69 ×10^-10

Explanation:

Given that the equation for the dissolution of AgCl in water is;

AgCl(s) ⇄Ag^+(aq) + Cl^+(aq)

Also, silver ion and chloride ion are in equilibrium with the undissociated AgCl hence we can write;

Ksp= [Ag+][Cl-]/ [AgCl]

Since the activity of the pure sold is 1, we now have;Ksp= [Ag+][Cl-]

If we know the solubility of AgCl in pure water to be 1.3 x 10^-5 M, from standard tables, and [Ag+]=[Cl-]= 1.3 x 10^-5 M = x

Then;

Ksp= x^2

Ksp= (1.3 x 10^-5)^2

Ksp= 1.69 ×10^-10

When Ag⁺ and Cl⁻ are in equilibrium with AgCl, the expression for Ksp is

[tex]Ksp = [Ag^{+} ][Cl^{+} ][/tex]

And its value is 1.77 × 10⁻¹⁰.

Let's consider the equation for the solution of AgCl.

AgCl(s) ⇄ Ag⁺(aq) + Cl⁻(aq)

The molar solubility of AgCl (S) at 25 °C is 1.33 × 10⁻⁵ M. We can use this information to calculate the solubility product (Ksp) through an ICE chart.

       AgCl(s) ⇄ Ag⁺(aq) + Cl⁻(aq)

I                          0             0

C                       +S           +S

E                        S              S

The solubility product (Ksp) for AgCl is:

[tex]Ksp = [Ag^{+} ][Cl^{+} ] = S.S = S^{2} = (1.33 \times 10^{-5} )^{2} = 1.77 \times 10^{-10}[/tex]

When Ag⁺ and Cl⁻ are in equilibrium with AgCl, the expression for Ksp is

[tex]Ksp = [Ag^{+} ][Cl^{+} ][/tex]

And its value is 1.77 × 10⁻¹⁰.

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Answer:

[C₆H₅NH₃⁺] = 0.0399 M

Explanation:

This excersise can be easily solved by the Henderson Hasselbach equation

C₆H₅NH₃Cl → C₆H₅NH₃⁺  + Cl⁻

pOH = pKb + log (salt/base)

As we have value of pH, we need to determine the pOH

14 - pH = pOH

pOH = 8.43  (14 - 5.57)

Now we replace data:

pOH = pKb + log ( C₆H₅NH₃⁺/  C₆H₅NH₂ )

8.43 = 9.13 + log (  C₆H₅NH₃⁺ / 0.2 )

-0.7 = log (  C₆H₅NH₃⁺ / 0.2 )

10⁻⁰'⁷ = C₆H₅NH₃⁺ / 0.2

0.19952 = C₆H₅NH₃⁺ / 0.2

C₆H₅NH₃⁺ = 0.19952 . 0.2  = 0.0399 M

Answer:

0.2 moles, assuming weight of dried salt

Explanation:

In order to determine the number of moles, we need to be aware of the mass of the substance in question.

Assuming the mass of the dehydrated [tex]KAl(SO_{4} )_{2}.H_{2} O[/tex] is 50g.

No. of moles = mass of substance/ molar mass of the substance.

= [tex]\frac{50g}{39+27+32*2+16*4*2\\)g/mol}[/tex]

= 0.2 moles moles.

Answer:

Molarity of sodium acetate you will need to add is 0.0324M

Explanation:

Assuming volume of the buffer is 1L.

The pH of a buffer can be determined using Henderson-Hasselbalch equation:

pH = pKa + log [A⁻] / [HA]

Where pKa is pKa of the weak acid,  [A⁻] molar concentration of conjugate base and [HA] molar concentration of weak acid

Replacing for the acetic buffer (pKa = 4.76):

pH = 4.76 + log [Sodium Acetate] / [Acetic Acid]

As you have 0.010 moles of acetic acid in 1L:

[Acetic Acid] = 0.010mol / 1L = 0.010M

And you require a pH of 5.27:

5.27 = 4.76 + log [Sodium Acetate] / [0.010M]

0.51 = log [Sodium Acetate] / [0.010M]

10^0.51 = [Sodium Acetate] / [0.010M]

3.236 =  [Sodium Acetate] / [0.010M]

3.236 [0.010M] = [Sodium Acetate]

0.0324M = [Sodium Acetate]

Answer:

A.∆s>0contribute to spontaneity.

Answer:

O, S, Te

Cl, Br, Se

Explanation:

Main group elements have an electronegativity that increases across a period (from left to right) and decreases down a group.

Each atom has its own value which you can find on the electronegativity chart.

Metals have low values

Nonmetals have high values

I'm your case:

O = 3.5

S = 2.5

Te = 2.1

Cl = 3.0

Br = 2.8

Se = 2.4

O, S, Te, and Cl, Br, Se are the correct order for the elements listed in order of decreasing electronegativity.

Electronegativity. is the tendency or the efficiency of an atom to attract the lone pair of electrons towards itself to become stable and complete their octave is known as electronegativity.

In the periodic table oxygen, fluorine and nitrogen are the three top, most electronegative elements, and from moving up to down in periodic table electronegativity. decreases and left to right increases.

Therefore,  the correct order for the elements listed in order of decreasing electronegativity is O, S, Te, and Cl, Br, Se.

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Answer:

The correct answer is option B and D, that is, halogen (chlorine) and hydroxyl.

Explanation:

An artificial sweetener and sugar substitute is sucralose. It is noncaloric as the majority of the sucralose ingested does not get dissociated within the body. The generation of sucralose takes place by the chlorination of sucrose. It is about 300 to 1000 times sweeter in comparison to sucrose.  

The consumption of sucralose is safe for both nondiabetics and diabetics, it is used in various food and beverage components due to non-caloric sweetener characteristics. It does not affect the levels of insulin and does not affect dental health. As it is produced by chlorination of sucrose, thus, the functional groups present in it are a halogen (chlorine) and a hydroxyl.  

Answer:

Rate constants are temperature dependent.

Explanation:

Reaction rate is used to quantify the rate of chemical reaction. There is a relationship between the reaction rate and the half-life of the reaction and the Gibbs free energy of activation, and the reaction rate is temperature dependent according to the equation.

For a reaction shown below

a A + b B ⇒ c C

The rate of reaction of the reaction is given by

[tex]r = k(T) [A]^{m}[B]^{n}[/tex]

where k(T) is the reaction constant, which is seen to be dependent on the temperature of the reaction.

Also, k(T) is numerically equal to

[tex]k(T) = Ae^{\frac{E_{a} }{RT} }[/tex]

where

r = reaction rate

A = pre exponential factor

[tex]E_{a}[/tex] = Activation energy

R = gas constant

T = temperature

and m and n are experimentally determined partial orders in [A] and [B]

Answer:

The compound is largely ionic with A as the cation.

Explanation:

A chemical bond is usually formed between two or more elements. A chemical bond may be ionic, covalent or polar covalent depending on the electro negativity difference between the atoms in the bond.

A large electro negativity difference usually implies an ionic bond. As a rule, when the electronegativity difference is greater than 2.0, the bond is considered ionic.

For the compound A2B, the electro negativity difference between the two atoms is about 2.2. This implies that A2B must be an ionic compound in which A is the cation and B is the anion.

Answer:

There should be one lithium, not two.

Explanation:

Lithium reacts with hydrogen at about 750°C to yield lithium hydride (LiH). LiH is white and powdery in appearance. It releases hydrogen gas when it reacts with water.

The correct formula for Lithium hydride is LiH and not Li2H because both lithium and hydrogen are univalent. Lithium has a valency of +1 while hydrogen has a valency of -1 in lithium hydride. Hydrides are formed between hydrogen and highly electro positive metals. In hydrides, hydrogen is forced to accept an electron from the highly electro positive metal.

Answer:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d² or [Ar] 3d² 4s²

Explanation:

Electron configuration can basically be referred to as the location of electron; how the electrons are arranged in the orbitals of the atoms.

Following Aufbau principle, electrons are arranged in the following order of orbitals.

1s 2s 2p 3s 3p 4s 3d and so on.

The s can hold a maximum of 2 electrons, p can hold a maximum of 6 electrons and d can hold a maximum of 10 electrons.

Titanium has an atomic number of 22. So the arrangement is given as;

Ti = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d²

The short hand notation is given as;

[Ar] 3d² 4s²

The electron configuration of Ti is

[tex]Ti: 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{2}[/tex]   or  [tex]Ti: [Ar] 4s^{2} 3d^{2}[/tex]

The electron configuration of an element is the distribution of electrons in atomic orbitals.

According to Aufbau's principle, the orbitals with lower energies are filled before the orbitals with higher energies.

We can know this order, using the diagonal rule (attached image).

The maximum number of electrons in each sublevel is:

Considering all these facts, and that Titanium has 22 electrons, the electron configuration of Ti is:

[tex]Ti: 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{2}[/tex]

Since [tex]1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6}[/tex] is the electron configuration of Argon, this can also be written as:

[tex]Ti: [Ar] 4s^{2} 3d^{2}[/tex]

The electron configuration of Ti is

[tex]Ti: 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{2}[/tex]   or  [tex]Ti: [Ar] 4s^{2} 3d^{2}[/tex]

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Answer::

Lower rate of reaction

Explanation:

Lower concentration of reactant in an experiment is indicative of fewer ions or atoms present, which means a slower rate of reaction. In a titration reaction for instance, the end point would take longer to be substantiated, thereby increasing volume of titres. This is further backed up by collision theory which states that more particles in a system improves combinations of molecules.

This however may not be the case if the iodine in question is  catalyst, in which case the change in concentration has no effect whatsoever on the reaction rte.

I hope this explanation fits the brief.

Answer:

B) Ionic

Explanation:

Answer:

104 48 Cd + 0 -1 e ---------> 104 47 Ag

Explanation:

In the process of electron capture, the nucleus captures an electron and thus converts a proton into a neutron with the emission of a neutrino. This process increases the Neutron/Proton ratio, the captured electron is usually from the K shell. An electron from a higher energy level now drops down to fill the vacancy in the K shell and characteristic X-ray is emitted. This process usually occurs where the Neutron/proton ratio is very low and the nucleus has insufficient energy to undergo positron emission.

For 104 48 Cd, the balanced equation for K electron capture is;

104 48 Cd + 0 -1 e ---------> 104 47 Ag

Answer:

2–Ethyl–3–methlypentanal.

Explanation:

To name the compound given in the question above, we must observe the following:

1. The functional group of the compound is Alkanal i.e Aldehyde,

—CHO and it is located at carbon 1.

Note: the aldehyde functional group is always at carbon 1 and there will be no need to state it's position in the compound.

2. The longest continuous carbon chain is 5 i.e pentane. But the presence of the functional group will replace the –e at the end of pentane with –al, making the name to the pentanal.

3. The substituents attached are:

a. Ethyl, CH2CH3 at carbon 2.

b. Methyl, CH3 at carbon 3.

4. Combine the above to get the name of the compound.

Therefore, the name of the compound is:

2–Ethyl–3–methlypentanal.

Answer:

Mass = 26.53 g

Explanation:

Heat of combustion = −1380.0 kJ/mol

This means 1 mol of the compound releases 1380 kJ

Molar mass = 44.53 g/mol

This means 1 mol of the compound has a mass of 44.53 g

How many grams would release 822kJ..?

First, we have to obtain the number of moles

1 mol = 1380

x = 822

x = 0.5957 moles

Moles = Mass / Molar mass

Mass = Molar mass * moles

Mass = 44.53 * 0.5957

Mass = 26.53 g

Answer:

The methane gas burns

Explanation:

The burning of methane gas is a combustion reaction. Combustion is an exothermic process. For all exothermic processes, ∆H is negative.

Combustion reaction involves the evolution of heat. The energy of reactants is greater than the energy of products hence the excess energy is given off in the form of heat leading to a negative value of the enthalpy of reaction, hence the answer.

Answer:

pH = 3.23

Explanation:

Before the addition of any NaOH, the only you have is a 0.020M acetic acid solution. That is in equilibrium with water as follows:

HC₂H₃O₂(aq) + H₂O(l) ⇄ C₂H₃O₂⁻(aq) + H₃O⁺(aq)

The Ka of this reaction is:

Ka = 1.8x10⁻⁵ = [C₂H₃O₂⁻] [H₃O⁺] / [HC₂H₃O₂]

Where [] are concentrations in equilibrium of each species

As you have in solution just HC₂H₃O₂, the equilibrium concentrations will be:

[HC₂H₃O₂] = 0.020M - X

[C₂H₃O₂⁻] = X

[H₃O⁺] = X

Where X is reaction coordinate.

Repalcing in Ka expression:

1.8x10⁻⁵ = [C₂H₃O₂⁻] [H₃O⁺] / [HC₂H₃O₂]

1.8x10⁻⁵ = [X] [X] / [0.020M - X]

3.6x10⁻⁷ - 1.8x10⁻⁵X = X²

3.6x10⁻⁷ - 1.8x10⁻⁵X - X² = 0

Solving for X:

X = -0.0006M → False solution. There is no negative concentrations

X = 0.000591M → Right solution.

As:

[H₃O⁺] = X

[H₃O⁺] = 0.000591M

As pH = -log[H₃O⁺]

Answer:

A. copper is highly water soluble. It will turn into 5 different hydrates as it absorbs more and more water.

b. Glycerol is easily soluble in water, due to the ability of the polyol groups to form hydrogen bonds with water molecules

c. octane is considered to be non-polar, it will not be soluble in water, since water is a polar solvent. This will happen because octane (hydrocarbons in general) contains neither ionic groups, nor polar functional groups that can interact with water molecules.

d. Nitric acid decomposes into water, nitrogen dioxide, and oxygen, forming a brownish yellow solution.

e. Barium carbonate is a white powder. It is insoluble in water and soluble in most acids

Explanation:

Answer:

5 .04 percent.

Explanation:

it is also known as sulfur dioxide. so it's 5.0.4 percent.

Your question is incomplete. Read below to find the content.

0.4 % is the percent composition of sulfur in SO2.

In the laboratory, sulfur dioxide is prepared by the reaction of metallic sulfite or a metallic bisulfite with dilute acid. For example, a reaction between the dilute sulphuric acid and sodium sulfite will result in the formation of SO2.

The percentage composition of a given compound is defined as the ratio of the amount of each element to the total amount of individual elements present in the compound multiplied by 100. Here, the quantity is measured in terms of grams of the elements present.

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Answer:

0.36 g of N2.

Explanation:

The following data were obtained from the question:

Temperature (T) = 25 °C

Volume (V) = 340 mL

Measured pressure = 730 torr

Vapour pressure = 23.76 torr

Mass of N2 =..?

First, we shall determine the true pressure of N2. This can be obtained as follow:

Measured pressure = 730 torr

Vapor pressure = 23.76 torr

True pressure =..?

True pressure = measured pressure – vapor pressure

True pressure = 730 – 23.76

True pressure = 706.24 torr.

Converting 706.24 torr to atm, we have:

760 torr = 1 atm

Therefore,

706.24 torr = 706.24 / 760 = 0.929 atm

Next, we shall convert 340 mL to L. This is illustrated below:

1000 mL = 1 L

Therefore,

340 mL = 340/1000 = 0.34 L

Next, we shall convert 25 °C to Kelvin temperature. This is illustrated below:

Temperature (K) = Temperature (°C) + 273

T(K) = T (°C) + 273

T (°C) = 25 °C

T(K) = 25 °C + 273

T (K) = 298 K

Next, we shall determine the number of mole of N2. This can be obtained as follow:

Pressure (P) = 0.929 atm

Volume (V) = 0.34 L

Temperature (T) = 298 K

Gas constant (R) = 0.0821 atm.L/Kmol

Number of mole (n) =...?

PV = nRT

0.929 x 0.34 = n x 0.0821 x 298

Divide both side by 0.0821 x 298

n = (0.929 x 0.34 ) /(0.0821 x 298)

n = 0.0129 mole

Finally, we shall determine the mass of N2 as shown below:

Mole of N2 = 0.0129 mole

Molar mass of N2 = 2x14 = 28 g/mol

Mass of N2 =.?

Mole = mass /Molar mass

0.0129 = mass of N2/ 28

Cross multiply

Mass of N2 = 0.0129 x 28

Mass of N2 = 0.36 g

Therefore, 0.36 g of N2 was collected.

Answer:

Helium and potassium

Explanation:

The density of helium is 0.18 and potassium 0.86, while lithium is 0.53

Answer:

The equilbrium concentration of NH₃(g) is 2.4 M

Explanation:

The balanced reaction is:

4 NH₃(g) + 7 O₂(g) ⇔ 2 N₂O₄(g) + 6 H₂O(g)

By stoichiometry of the reaction,  2 moles of N₂O₄ are formed from 4 moles of NH₃.

Considering that the concentration is [tex]concentration=\frac{number of moles}{volume}[/tex] and with a volume of 1 liter, it is possible to apply the following rule of three: if 2 M of N₂O₄ are formed from 4 M of NH₃, 0.6 M of N₂O₄ from what concentration  of NH₃ are formed?

[tex]concentration of NH_{3}=\frac{0.6 M of N_{2}O_{3} *4MofNH_{3} }{2 M of N_{2}O_{3} }[/tex]

concentration of NH₃= 1.2 M

By subtracting the moles of NH3 in equilibrium from the moles of NH₃ initially, you will see how many moles of NH₃ were converted and remain in equilibrium: 3.6 M - 1.2 M= 2.4 M

The equilbrium concentration of NH₃(g) is 2.4 M

Answer:

hi here goes your answer

Explanation:

iv. The lower the PH, the weaker the base