Planet A is an inner planet with no moon and hardly any atmosphere. Planet B is an inner planet with no moon but with a dense atmosphere. Which pair of planets is being described?
A.
Mars and Venus
B.
Mercury and Earth
C.
Mercury and Venus
D.
Mars and Earth

Answer:

C. A measure of disorder :)

Answer:

Problem Details

The element europium exists in nature as two isotopes:  151Eu has a mass of 150.9196 amu, and 153Eu has a mass of 152.9209 amu. The average atomic mass of europium is 151.96 amu. Calculate the relative abundance of the two europium isotopes.

answer:

151Eu = 48%, 153Eu = 52%

Answer:

pH = 3.49

Explanation:

We have a buffer system formed by a weak acid (HNO₂) and its conjugate base (NO₂⁻ coming from KNO₂). We can calculate the pH  of a buffer ssytem using the Henderson-Hasselbach equation.

pH = pKa + log [base] / [acid]

pH = -log Ka + log [NO₂⁻] / [HNO₂]

pH = -log 4.50 × 10⁻⁴ + log 0.290 M / 0.210 M

pH = 3.49

The pH of the solution containing 0.210 M nitrous acid (HNO₂) and 0.290 M potassium nitrite (KNO₂) is 3.49

We'll begin by calculating the the pKa of acid. This can be obtained as follow:

Acid dissociation constant (Ka) = 4.50×10¯⁴

pKa = –Log Ka

pKa = –Log 4.50×10¯⁴

pKa = 3.35

Concentration of HNO₂, [HNO₂] = 0.210 M

Concentration of KNO₂, [KNO₂] = 0.290 M

The pH of the solution can obtain by using the Henderson-Hasselbach equation as illustrated below:

pH = pKa+ log [NO₂⁻] / [HNO₂]

pH = 3.35 + log (0.290 / 0.210)

Thus, the pH of the solution is 3.49

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Answer: The standard cell potential for the cell is +0.51 V

Explanation:

Given : [tex]E^0_{Ni^{2+}/Ni}=-0.25V[/tex]

[tex]E^0_{Zn^{2+}/Zn}=-0.76V[/tex]

The given reaction is:

[tex]Ni^{2+}(aq)+Zn(s)\rightarrow Zn^{2+}(aq)+Ni(s)[/tex]

As nickel is undergoing reduction, it acts as cathode and Zinc is undergoing oxidation, so it acts as anode.

[tex]E^0_{cell}=E^0_{cathode}-E^0_{anode}[/tex]

where both [tex]E^0[/tex]  are standard reduction potentials.

Thus putting the values we get:

[tex]E^0_{cell}=-0.25-(-0.76)[/tex]

[tex]E^0_{cell}=0.51V[/tex]

Thus the standard cell potential for the cell is +0.51 V

Answer:

0.423 m.

Explanation:

The following data were obtained from the question:

Mass of glycine (NH2CH2COOH) = 141.5 g

Mass of water = 4.456 kg

Molality =.?

Next, we shall determine the number of mole in 141.5 g of glycine (NH2CH2COOH.

This is illustrated below:

Mass of glycine (NH2CH2COOH) = 141.5 g

Molar mass of glycine (NH2CH2COOH) = 14 + (2x1) + 12 + (2x1) + 12 + 16 + 16 + 1 = 75 g/mol

Mole of glycine (NH2CH2COOH) =.?

Mole = mass /Molar mass

Mole of glycine (NH2CH2COOH) = 141.5/75

Mole of glycine (NH2CH2COOH) = 1.887 moles

Finally, we shall determine the molality of the solution as follow:

Molality is simply defined as the mole of solute per kilogram of water. Mathematically it is expressed as:

Molality = mole / mass (kg) of water

With the above formula, we can obtain the molality of the solution as follow:

Mole of glycine (NH2CH2COOH) = 1.887 moles

Mass of water = 4.456 kg

Molality =.?

Molality = mole /mass (kg) of water

Molality =1.887/4.456

Molality = 0.423 m

Therefore, the molality of the solution is 0.423 m

Answer:

466 torr

Explanation:

Step 1: Given data

Step 2: Calculate the final pressure

Since we have a gas changing at a constant temperature, we can calculate the final pressure using Boyle's law.

P₁ × V₁ = P₂ × V₂

P₂ = P₁ × V₁ / V₂

P₂ = 626 torr × 5.00 L / 6.72 L

P₂ = 466 torr

Answer:

1. In the compound, H3C-NH-CH2-CH3, there are no chiral centers present, chiral centers refer to the configuration in which carbon is attached with four different groups. In the molecules, as there are no chiral centers, therefore the molecule is optically inactive, that is, it will not demonstrate pair of an enantiomer is one of the essential characteristics of optically active compounds is the possession of enantiomeric pairs.  

2. On the nitrogen of aniline, the lone pair of electrons can produce hydrogen bonds, play an essential function in basicity, play an essential role in dipole moment or polarity, and wit the increase in solubility there is an increase in the formation of the hydrogen bond, eventually increasing to boiling point. However, the melting point is not affected. As the melting point is the characteristic of the packing efficacy of a molecule and does not rely upon the anilinic nitrogen's lone pairs.  

3. With the increase in the tendency to donate an electron, basicity increases. However, if the electron is taking part in resonance, the donation will not take place easily, and the compound will be the least basic. Apart from cyclohexyl amine, in all the other given compounds, the lone pair of nitrogen takes part in the process of delocalization or conjugation. Thus, cyclohexyl amine will be most basic as the lone pairs are easily available for donation.  

Answer:

4.22

Explanation:

According to the question, the pOH of the solution is 9.78. You may recall that pOH is the hydroxide concentration of a solution.

Also pOH = -log[OH^-]. Hence the pOH is obtained from the hydroxide ion concentration.

Finally, pH + pOH =14

Hence;

pH = 14-pOH

pH= 14-9.78 = 4.22

pH= 4.22

Answer:

the object will regain its original form as soon as the deforming force is removed. ... Flexibility means the object is just easily deformed, and will stay that way.

Explanation:

Answer:

Au^3+(aq) +3e ------> Au(s). 1.50 V

Explanation:

When we construct the galvanic cell, our intention is to produce energy by spontaneous electrochemical reactions. In order to have a spontaneous electrochemical reaction, E°cell must be positive. The more positive the value of E°cell, the more spontaneous the reaction is.

E°cell= E°cathode - E°anode

If E°cathode= 1.50 V

E°anode= -0.25 V

E°cell= 1.50 -(-0.25)

E°cell= 1.75 V

Hence the process; Au^3+(aq) +3e ------> Au(s) yields the highest standard cell potential

Answer:

C. Aluminum Nitrate (Al(NO3)3)

Explanation:

This is because, when Aluminium nitrate dissolves in water, it dissociates to form four ions ( one aluminium ion and three nitrate ions ). Since colligative property depends on number of particles or ions present ( roult's law ), this will create much effect.

[tex]Al(NO _{3} )_{3(aq)} → Al {}^{3 + } _{(aq)} + 3NO {}^{ - } _{(aq)}[/tex]

Answer:

aluminum nitrate (Al(NO3)3)

it has the greatest effect on collimation properties .

Explanation:

(c) is correct option

Answer:

The final temperature of the entire water sample after all the ice is melted, is 12,9°C. We should realize that if there is no loss of heat in our system, the sum of lost or gained heat is 0.  It is logical to say that the temperature has decreased because the ice gave the water "heat" and cooled it

Thats all i know

Answer:

Chemistry is one of the causes for global warming, and in some cases it can even cause certain illnesses.

Answer:

Chemists have both hurt the environment and helped the environment by their actions.

Explanation:

<3

Answer: C

Explanation:

The article was sourced from the Oak National Laboratory

Which reasons did you include in your response? Check all of the boxes that apply.

1. The article does not present original research.

and

3. The article has references to primary sources.

Answer:

C

Explanation:

Which reasons did you include in your response? Check all of the boxes that apply.

The article does not present original research.

The article summarizes other research.

The article has references to primary sources.

Answer:

The volume of the container is 59.112 L

Explanation:

Given that,

Number of moles of Oxygen, n = 3

Temperature of the gas, T = 300 K

Pressure of the gas, P = 1.25 atm

We need to find the volume of the container. For a gas, we know that,

PV = nRT

V is volume

R is gas constant, R =  0.0821 atm-L/mol-K

So,

[tex]V=\dfrac{nRT}{P}\\\\V=\dfrac{3\ mol\times 0.0821\ L-atm/mol-K \times 300\ K}{1.25\ atm}\\\\V=59.112\ L[/tex]

So, the volume of the container is 59.112 L

Explanation:

a. Esters

b. Carboxylic acids

c. Esters (ethyl hexanoate smells like pineapple)

d. Carboxylic acids (produces a carboxylic salt)

For the given phrases the following description is better.

a. Esters

b. Carboxylic acids

c. Esters (ethyl hexanoate smells like pineapple)

d. Carboxylic acids (produces a carboxylic salt)

An ester is a synthetic compound got from a corrosive in which somewhere around one - OH hydroxyl bunch is supplanted by an - O-alkyl (alkoxy) bunch, as in the replacement response of a carboxylic acid and a liquor.

Carboxylic acid is any of a class of natural mixtures in which a carbon (C) particle is clung to an oxygen (O) molecule by a twofold bond and to a hydroxyl bunch (―OH) by a solitary bond.

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Answer:

d. carboxyl

Explanation:

The presence of carbonyl group (>C=O)) and a hydroxyl group ( (−OH) on the same carbon atom is called a "carboxyl" group. A carboxyl group is represented as COOH and acts as the functional group part of carboxylic acids.

For example:

Hence, the correct option is "d. carboxyl ".

Answer:

Ammonium nitrate is a chemical compound with the chemical formula NH₄NO₃. It is a white crystalline solid consisting of ions of ammonium and nitrate.

Answer:

The answer is "Tertiary carbon".

Explanation:

Accent to the results, the carbon-bromine bond is weak, whenever, the bromine is connected to tertiary carbon so, bonding energy is separation for methyl-carbon, which is connected to the bromine = 70 kcal/mol and for the primary energy to the secondary energy is=  68 kcal/mol, and for tertiary CO2 = 65 kcal/mol.

The stronger the energy dissociating connection and the weaker, its power dissociation connection and its weaker bond becomes connecting with a tertiary carbon, that's why "Tertiary carbon" is the correct answer.

Answer:

volume versus temperature, because they are also directly proportional.

Explanation:

Just took the test!

Explanation:

chemical formula tells you the specific elements included in the compound and the number of atoms of each. The letters in a chemical formula are the symbols for the specific elements. So for example, H means hydrogen.

Explanation:

A chemical formula is a way of presenting information about the chemical properties of atoms that contribute a particular chemical compound or molecule, using chemical elements.

Answer:

[H₃O⁺] = 2.5 × 10⁻¹³ M

pH = 12.6

Explanation:

Step 1: Given data

Concentration of OH⁻: 0.04 M

Step 2: Calculate the concentration of H₃O⁺

Let's consider the self-ionization of water reaction.

2 H₂O(l) ⇄ OH⁻(aq) + H₃O⁺(aq)

The ionic product of water is:

Kw = [OH⁻] × [H₃O⁺] = 10⁻¹⁴

[H₃O⁺] = 10⁻¹⁴ / [OH⁻]

[H₃O⁺] = 10⁻¹⁴ / 0.04

[H₃O⁺] = 2.5 × 10⁻¹³ M

Step 3: Calculate the pH

The pH is:

pH = -log [H₃O⁺] = -log 2.5 × 10⁻¹³ = 12.6

Spectra can be used as an evidence that nuclear fusion occurs in the star through the ability of the elements generated to absorb light at specific wavelength.

The internal part of the star is made up of hydrogen gas, with a little helium.

The helium atom is formed through the nuclear fusion reaction that occurs in the core of the star.

Nuclear fusion reaction involves the combination of two or more atoms which leads to the formation of a new atom with the emission of great energy. This reaction leads to formation of helium elements in the core of the stars.

To detect if nuclear fusion reaction is occurring in the stars, a spectrum is used.

Because each element emits or absorbs light only at specific wavelengths, the chemical composition of stars can be determined using a spectrum.

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Answer:

1. 36

2. Two

Explanation:

The Lewis structure shows the valence electrons present in a compound. Usually the valence electrons are shown as dot structures around the symbol of the elements involved in the compound.

For a compound AB4 where B is more electronegative than A and A has 8 electrons in its valence shell, there will be thirty six valence electrons on the outermost shell of the molecule.

There are six electron pair domains present in the molecule, four bond pairs and two lone pairs. The molecule is in a square planar geometry.

Answer: a- 36 valence electrons

b- 14 lone pairs

Explanation:

Valence is equal to A + 4B = 8 + 4(7)

With 4 bonds between A and the 4 B, that is 36 valence minus 8 electrons in those pairs = 28. 28 is 14 lone pairs.

Answer:

β particles

Explanation:

The most common radioactive isotope of carbon is C-13.

The unbalanced nuclear equation is

[tex]\rm _{6}^{13}C \longrightarrow \, ? + \, _{7}^{13N}[/tex]

Let's write the question mark as a nuclear symbol.

[tex]\rm _{6}^{13}C} \longrightarrow \, _{Z}^{A}X+ \, _{7}^{13}N[/tex]

The main point to remember in balancing nuclear equations is that the sums of the superscripts and the subscripts must be the same on each side of the equation.  

Then

13 =  A + 13, so A =  13 - 13 = 0, and

6 = Z + 7, so Z  = 6 - 7 = -1

Then, your nuclear equation becomes

[tex]\rm _{6}^{13}C \longrightarrow \, _{-1}^{0}M + \, _{7}^{13}N[/tex]

The particle with "zero" mass and a charge of -1 is an electron, so the balanced nuclear equation is

[tex]\rm _{6}^{13}C \longrightarrow \, _{-1}^{0}e + \, _{7}^{13}N[/tex]

The radiation consists of β particles (electrons)

Answer:

I think think that the one above me is beta radiation

Explanation:

Answer:

Ionic compounds have high melting points.

Ionic compounds are hard and brittle.

Ionic compounds dissociate into ions when dissolved in water.

Solutions of ionic compounds and melted ionic compounds conduct electricity, but solid materials do not.

Explanation:

ℯ ℴ ℴ ℴℯℯ

it has a weak adhesion

Answer:

68%

Explanation:

Since we need a percentage we can use any number we want for our initial value.

5(1/2)^900/1620 = 3.40

(3.40 / 5)*100 = 68%

To make sure lets use a different initial amount

1(1/2)^900/1620 = 0.68

(0.68/1) * 100 = 68%

To solve this question, we'll assume the initial amount of radium-226 to be 1.

Now, we shall proceed to obtaining the percentage of radium-226 that will after 900 years. This can be obtained as illustrated below:

Determination of the number of half-lives that has elapsed.

Half-life (t½) = 1620 years

Time (t) = 900 years

[tex]n = \frac{t}{t_{1/2}}\\\\n = \frac{900}{1620}\\\\n = \frac{5}{9}[/tex]

Determination of the amount remaining

Initial amount (N₀) = 1

Number of half-lives (n) = 5/9

[tex]N = \frac{N_{0} }{2^{n}}\\\\N = \frac{1}{2^{5/9}}[/tex]

Determination of the percentage remaining.

Initial amount (N₀) = 1

Amount remaining (N) = 0.68

Percentage remaining = N/N₀ × 100

Percentage remaining = 0.68/1 × 100

Therefore, the percentage amount of radium-226 that remains after 900 years is 68%

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Answer:

8.6×10^-2

Explanation:

The reaction is;

Mg(s) + Fe^2+(aq) -----> Mg^2+(aq) + Fe(s)

This implies that;

Q = [Mg^2+]/[Fe^2+]

But;

[Fe2+]= 3.60 M

[Mg2+]= 0.310 M

Q= [0.310 M]/[3.60 M]

Q= 0.086

Q= 8.6×10^-2