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Answer:

66.5753 amu

Explanation:

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

Isotope A (⁶⁵X):

Mass of A = 65.0457 amu

Abundance of A = 20.53%

Isotope B (⁶⁷X):

Mass of B = 66.9704 amu

Abundance of B = 79.47%

Atomic mass of X =?

The atomic mass of X can be obtained as follow:

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

= [(65.0457 × 20.53)/100] + [(66.9704 × 79.47)/100]

= 13.3539 + 53.2214

= 66.5753 amu

Therefore, the atomic mass of X is 66.5753 amu.

Element X, with an atomic mass of 66.58 amu, has 2 naturally occurring isotopes, ⁶⁵X (65.0457 amu, 20.53%) and ⁶⁷X (66.9704 amu,  79.47%).

The average atomic mass (atomic mass) of an element is the sum of the masses of its isotopes, each multiplied by its natural abundance.

Element X has 2 isotopes:

We can calculate the average atomic mass of X using the following expression.

mX = m⁶⁵X × ab⁶⁵X + m⁶⁷X × ab⁶⁷X

mX = 65.0457 amu × 0.2053 + 66.9704 amu × 0.7947

mX = 66.58 amu

Element X, with an atomic mass of 66.58 amu, has 2 naturally occurring isotopes, ⁶⁵X (65.0457 amu, 20.53%) and ⁶⁷X (66.9704 amu,  79.47%).

Learn more about atomic mass here: https://brainly.com/question/6200158

Answer:

11

Explanation:

Moles of KOH = [tex]10^{-2}[/tex]

Volume of water = 10 liters

Concentration of KOH is given by

[tex][KOH]=\dfrac{10^{-2}}{10}\\\Rightarrow [KOH]=10^{-3}\ \text{M}[/tex]

[tex][KOH][/tex] is strong base so we have the following relation

[tex][KOH]=[OH^{-}]=10^{-3}\ \text{M}[/tex]

[tex]pOH=-\log [OH^{-}]=-\log10^{-3}[/tex]

[tex]\Rightarrow pH=14-3=11[/tex]

So, pH of the solution is 11

Answer:

I believe it's chemical

Answer:

physical

Explanation:

it's not changing form or substance

Answer:

1.09 × 10⁻⁷ m

UV region

Explanation:

Step 1: Given and required data

Energy of the photon of light (E): 1.83 × 10⁻¹⁸ J

Planck's constant (h): 6.63 × 10⁻³⁴ J.s

Speed of light (c): 3.00 × 10⁸ m/s

Step 2: Calculate the wavelength (λ) of this photon of light

We will use the Planck-Einstein's relation.

E = h × c/λ

λ = h × c/E

λ = 6.63 × 10⁻³⁴ J.s × (3.00 × 10⁸ m/s)/1.83 × 10⁻¹⁸ J = 1.09 × 10⁻⁷ m

This wavelenght falls in the UV region of the electromagnetic spectrum.

Answer:

See explanation

Explanation:

For Fe;

Fe2+(aq) + 2H+(aq) + S2-(aq) ----> FeS(s) + H2(g)

For Ni

Ni2+(aq) + 2H+(aq) + S2-(aq) ----> NiS(s) + H2(g)

For Cr

2Cr3+(aq) + 6H+(aq) + 3S2-(aq) ----->Cr2S3(s) + 3H2(g)

We must remember that in writing these equations, the number of electrons lost or gained must be balanced. The number of electrons lost by the metal must equal the number of electrons gained by hydrogen. This rule was followed in writing all the equations above.

Answer:

The transfer was essential to understand the mutation and the possibility of new, more resistant strains in microorganisms.

Explanation:

the transfer of microorganisms is based on the transfer of genetic data through conductive pathways that penetrate the membranes, called pili or genetic bridges.

These mutated genes with higher resistance are transmitted and resistance is generated in entire populations and even species.

Answer:

I think the answer is b

Explanation:

the paragraph states, that it is an experiment to see if there is any oxygen in the water

Answer:

[tex]M_{C_9H_{13}NO_3}=183.23g/mol[/tex]

Explanation:

Hello!

In this case, since the molar mass of a chemical compound is computed by averaging the atomic mass of each element in the molecule and the amount of atoms; which in this case there are 9 carbon atoms, 13 hydrogen atoms, 1 nitrogen atom and 3 oxygen atoms; thus, we compute the average as shown below:

[tex]M_{C_9H_{13}NO_3}=m_C*9+m_H*13+m_N+m_O*3[/tex]

Now, we plug in the atomic masses to obtain:

[tex]M_{C_9H_{13}NO_3}=12.01*9+1.01*13+14.01+16.00*3\\\\M_{C_9H_{13}NO_3}=183.23g/mol[/tex]

Best regards!

Answer:

the answer is B:) have a good day

Answer:

Option C. 24 days / 4 grams

Explanation:

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

Days Elapsed >>>> Mass Remaining

0 >>>>>>>>>>>>>>> 16

12 >>>>>>>>>>>>>>> 11

24 >>>>>>>>>>>>>>> 8

36 >>>>>>>>>>>>>>> 6

A. Determination of the half-life of Thorium-234.

To determine the half-life, it is important to know the definition of half life.

Half-life is defined as the time taken for a substance to reduce to half its original mass.

From the table given above, we can see that the original mass of the isotope is 16 g (i.e at 0 day). By day 24, the mass of the isotope is 8 g (i.e half the original mass). Thus, the half-life of the isotope is 24 days.

B. Determination of the mass of the isotope remaining after 2 half lives.

Original amount (N₀) = 16 g

Number of half-lives (n) = 2

Amount remaining (N) =?

N = 1/2ⁿ × N₀

N = 1/2² × 16

N = 1/4 × 16

N = 4 g

Thus, 4 g of the isotope is remaining after 2 half lives.

Summay:

Half-life = 24 days

Amount remaining after 2 half-lives = 4 g

Option C gives the correct answer to the question.

Answer:  It is more difficult to remove a valence electron from a Chlorine (Cl) atom

Explanation:

Ionization energy is the energy required to remove the valence electron from an isolated gaseous atom.

Magnesium (Mg) is the 12th element of periodic table and has an atomic number of 12. The electronic configuration is 2, 8, 2. It can easily lose its valence 2 electrons to attain stable configuration.

Chlorine (Cl) is the 17th element of periodic table and has an atomic number of 17. The electronic configuration is 2, 8, 7. It has a tendency to gain electron to attain stable configuration. It cannot lose its valence electron easily as the valence electrons experience more nuclear charge.

Thus it is more difficult to remove a valence electron from a Chlorine (Cl) atom

Chlorine(Cl) is the more difficult to remove a valence electron from which is

because it needs one electron to achieve a stable octet configuration.

Magnesium (Mg) is an element which has an atomic number of 12. The

electronic configuration is 2, 8, 2. This means it has to lose its  2 valence

electrons needed to attain a stable octet configuration.

Chlorine (Cl) is an element which has an atomic number of 17. The electronic

configuration is 2, 8, 7. This means it has to gain one valence electrons

needed to attain a stable octet configuration.

Thus it is more difficult to remove a valence electron from a Chlorine (Cl)

atom than Magnesium atom.

Read more on https://brainly.com/question/20714034

Answer:

44Kj

Explanation:

These are the equations for the reaction described in the question,

Vaporization which can be defined as transition of substance from liquid phase to vapor

H2(g)+ 1/2 O2(g) ------>H2O(g). Δ H

-241.8kj -------eqn(1)

H2(g)+ 1/2 O2(g) ------>H2O(l).

Δ H =285.8kj ---------eqn(2)

But from the second equation we can see that it moves from gas to liquid, we we rewrite the equation for vaporization of water as

H2O(l) ------>>H2O(g)---------------eqn(3)

But the equation from eqn(2) the eqn does go with vaporization so we can re- write as

H2O ------> H2(g)+ 1/2 O2(g)

Δ H= 285.8kj ---------------eqn(4)

To find Delta h of the vaporization of water at these conditions, we sum up eqn(1) and eqn(4)

Δ H=285.8kj +(-241.8kj)= 44kj

Answer:

Seven electrons.

Explanation:

There are seven valence electrons in each fluorine atom because it belongs to halogens. Fluorine atom requires one electron to complete its valence shell to become stable so for that it form both ionic and covalent bonds with different atoms. It makes ionic bond with alkali metals by accepting one electron to complete its valence shell and also make covalent bond by sharing of electrons.

Answer:

1) Mass =  890.96 g

2) Mass =  7.67 g

3) 507.65 ×10²³ atoms

Explanation:

1) Given data:

Number of moles of lead = 4.3×10⁻³ mol

Mass of lead = ?

Solution:

Mass = number of moles × molar mass

Molar mass of lead = 207.2 g/mol

by putting values,

Mass = 4.3×10⁻³ mol × 207.2 g/mol

Mass =  890.96 g

2) Given data:

Number of atoms of antimony = 3.8×10²² atoms

Mass of antimony = ?

Solution:

1 mole contain 6.022 ×10²³ atoms

3.8×10²² atoms × 1 mol / 6.022 ×10²³ atoms

0.63×10⁻¹ mol

0.063 mol

Mass:

Mass = number of moles × molar mass

Molar mass of lead = 121.76 g/mol

Mass = 0.063 mol ×  121.76 g/mol

Mass =  7.67 g

3) Given data:

Mass of tungsten = 15.5 Kg (15.5 kg × 1000 g/ 1kg = 15500 g)

Number of atoms = ?

Solution:

Number of moles of tungsten:

Number of moles = mass/molar mass

Number of moles = 15500 g / 183.84 g/mol

Number of moles = 84.3 mol

1 mole contain 6.022 ×10²³ atoms

84.3 mol  × 6.022 ×10²³ atoms / 1mol

507.65 ×10²³ atoms

Answer:

oxygen

if it's helpful ❤❤

Answer:

[tex]n_{Al}=6.00molAl\\\\n_{S}=9.00molS\\\\n_{O}=36.0molO[/tex]

Explanation:

Hello!

In this case, when analyzing the moles of an element inside a compound, we need to keep in mind that a mole ratio should be set up; thus, for aluminum sulfate, we have the following ones:

[tex]\frac{2molAl}{1molAl_2(SO_4)_3} \\\\\frac{3molS}{1molAl_2(SO_4)_3} \\\\\frac{12molO}{1mol1molAl_2(SO_4)_3}[/tex]

Thus, starting by 3.00 moles of aluminum sulfate, the moles of each element turn out:

[tex]n_{Al}=3.00molAl_2(SO_4)_3*\frac{2molAl}{1molAl_2(SO_4)_3} =6.00molAl\\\\n_{S}=3.00molAl_2(SO_4)_3*\frac{3molS}{1molAl_2(SO_4)_3} =9.00molS\\\\n_{O}=3.00molAl_2(SO_4)_3*\frac{12molO}{1molAl_2(SO_4)_3}=36.0molO[/tex]

Best regards!

Answer:

B

Explanation:

Answer:

atomic number of phosphorous is 15. It has zero charges because it has equal number of protons and electrons

Explanation:

Answer:

53.31g of FeCl3

Explanation:

The equation of the reaction is given as;

2Fe(s)  + 3Cl2(g) --> 2FeCl3(s)

From the stochiometry of the reaction;

2 mol   :    3 mol       :   2 mol

112g     :      213g      :     324.4g

Converting the masses given to moles;

Number of moles of Fe = mass / molar mass = 22.5 / 56 = 0.4018

Number of moles of Cl2 = mass / molar mass = 35 /  71 = 0.4930

In this reaction, the limiting reactant is Cl2

213 g of Cl2 produces 324.4g of FeCl3,

35g of Cl2 would produce xg of FeCl3

213 = 324.4

35 = x

x = (35 * 324.4) / 213 = 53.31g

one if them is phosphate

Answer:

c. the amount of fossil fuels being burned increased

Explanation:

Carbon dioxide gas concentration increased over the time due to burning of fossil fuels increased. Fossil fuels are organic compounds which releases carbondioxide gas as a result of burning of fossil fuels in the engines of vehicles and industries. With the passage of time, number of vehicles increases in the world which needs more fossil fuels and due to burning of that fossil fuels, more carbondioxide gas is released.

Answer:

nitrogen

Explanation:

The atmosphere contains many gases, most in small amounts, including some pollutants and greenhouse gases. The most abundant gas in the atmosphere is nitrogen, with oxygen second. Argon, an inert gas, is the third most abundant gas in the atmosphere. Why do I care?

nitrogen is the most abundant gas in the atmosphere

Answer:

They are resonance contributors

Explanation:

Resonance structures are structures that differ only in the distribution or placement of electrons.

Considering the two structures, we can easily see that the two species have the same total number of bonds and electrons differing only in the distribution of these electrons.

Hence, they are resonance contributors.

Answer:

See answer below

Explanation:

In this case, I will put the original photo of this exercise, because we are missing one data. The first picture is the original exercise.

Now, according to this, we need to make a serial dilution of CO(NO₃)₂. We don't know the volume of this solution, but we do know the total volume of the preparing solution (In the picture states that the total volume will be 10 mL).

So, we know the final volume of the solutions to be prepared, so, le'ts use the expression that will help us to solve this:

C₁V₁ = C₂V₂

Where:

C₁: Concentration of the given solution (stock)

V₁: volume required to prepare the dilluted solution

C₂; Concentration of the dilluted solution

V₂: Total volume of the dilluted solution.

Now that we know the expression to use and the meaning of each value, let's prepare the solutions:

To prepare 10 mL of 0.1 M using a 0.25 M, we will replace these values in the above expression; from there, we will solve for V₁, that value will tell us the required volume to prepare solution 2, and then, by difference we can calculate the volume of water:

Volume of water (Vw) =V₂ - V₁  

Now replacing the values:

0.25V₁ = 0.1 * 10

V₁ = 1/0.25 = 4 mL

This means that we need 4 mL of the stock to prepare the 0.1 M of dilluted solution, therefore, the volume of water required is:

Vw = 10 - 4

Using these same steps for the other two solutions we will get V1 and V2 for both of them. In this case, I will go straight to the procedure without further explanation because it's the same of this one.

For solution 2:

0.1V₁ = 0.05 * 10

V₁ = 0.5/0.1

Vw = 10 - 5

Finally for solution 3:

V₁ = 0.01 * 10 / 0.05

Vw = 10 - 2 mL

Hope this helps

Answer:

exercise every day and also make healthy choices in his diet

Explanation:

This is going to prevent Xander from getting more overweight and will help him lose some pounds.

This is also something I need to do lol

<3

Answer:

A

Explanation:

Exercise every day and also make healthy choices in his diet

Answer: (2) releases 2260 J/g of heat energy

Explanation:

Latent heat of vaporization is the amount of heat required to convert 1 mole of liquid to gas at atmospheric pressure.

Latent heat of condensation is energy released when 1 mole of  vapor condenses to form liquid droplets.

The temperature does not change during this process, so heat released goes into changing the state of the substance, thus it is called latent which means hidden. The energy released in this process is same in magnitude as latent heat of vaporization. The heat of condensation of water vapour is about 2,260 J/g.

Phase transition refers to the changes in the states of matter between gas, liquids, and solids.

The correct answer is:

Option 2. releases 2260 J/g of heat energy

The process can be explained as:

1. Condensation is the process of conversion of water vapor into the liquid state.

2. Latent heat of vaporization is defined as the amount of heat required for 1 mole of liquid to convert into a gaseous phase at atmospheric pressure.

3. The change in the temperature does not occur during the condensation, and the heat required for the phase transition is latent heat. The heat of condensation of water vapor is 2,260 J/g.

Thus, the correct answer is Option 2.

To know more about condensation, refer to the following link:

https://brainly.com/question/15563071