Which of the following sets of elements could replace the generic "X" symbol with their own to produce a valid dot notation for the element(s)?



Select one:

a.
carbon, silicon, and germanium


b.
oxygen, sulfur, and selenium


c.
boron, aluminum, and gallium


d.
nitrogen, phosphorus and arsenic

Answer:

1.18 x 10⁵

Explanation:

3.14 x 10⁻² / 2.65 x 10⁻⁷ = 1.18 x 10⁵

When performing division, the final answer should have the same number of significant figures as the number with the smallest number of sig figs. In this case, both of the given numbers have 3 sig figs, meaning the final answer should have this many as well.

The decrease in the freezing point of the solution is −1.86oC.

Now we know that the freezing point depression of a solid is a colligative property of the solution.

Thus we have that;

ΔT = K m i

ΔT = freezing point depression

K = freezing constant

m = molality of the solution

i = Van't Hoff factor

Thus;

molality =  1 mol/1 Kg = 1 m

ΔT = −1.86oC/m * 1 m * 1

ΔT =−1.86oC

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Answer:

Beryllium-9 is the isotope of beryllium with relative atomic mass 9.

Molality of C2H5OH is 1.1.27m.



What is Molality?

Molality is no.of moles present in One Kg solution .

Molality is represented by m

m= no.of moles/ weigt of solution in kg

Given is Molarity= 51.30M

molar mass of C2H5OH is 46g / mol , Density =0.9349g/ ml

Density=m/V

V = 107 ml

Molarity= no of moles/ Volume

51.5×46×107= x × 1000

weight of C2H5OH = 27.7g

molality = 27.7/1000××46

m= 1.27m

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Taking into account the definition of Avogadro's number and molar mass, 4.806 grams of water are present in 1.61×10²³ molecules.

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.

The molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.

Taking into account the definition of Avogadro's Number, you can apply the following rule of three: if 6.023×10²³ molecules are contained in 1 mole of water, then 1.61×10²³ molecules are contained in how many moles of water?

amount of moles of water= (1.61×10²³ molecules× 1 mole)÷ 6.023×10²³ molecules

amount of moles of water= 0.267 moles

Now, taking into account the definition of molar mass, and knowing that the molar mass of water is 18 g/mole, you can apply the following rule of three: If by definition of molar mass 1 mole of the compound contains 18 grams, 0.267 moles of the compound contains how much mass?

[tex]mass= \frac{0.267 molesx 18 grams}{1 mole}[/tex]

mass= 4.806 grams

Finally, 4.806 grams of water are present in 1.61×10²³ molecules.

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The pH can be defined as the negative logarithm of the hydrogen ion concentration of the solution.

What we call the pH can be defined as the negative logarithm of the hydrogen ion concentration of the solution. We are aware that we can use the relation [H+]  [OH-]  = 1 * 10^-14 to handle the enormity of this problem.

Now, let us go about solving the problems;

1. pH = -log(1 x 10-7) = 7

2.  [H+]=  1 * 10^-14/ 1 x 10^-3

pH =  -log(  1 * 10^-11)

pH = 11

3. pH = -log( 1 x 10^-2)

pH = 2

4. pH = -log(  1 x 10^-10)

pH = 10

5.  [H+]=  1 * 10^-14/ 1 x 10^-8

[H+]=  1 * 10^-6

pH = 6

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The transformations that result in increase in entropy are those that result in increased disorderliness and they are:

The entropy of  a system is a measure of the degree of randomness or disorderliness of a system.

When a system changes from a more ordered state to a more disordered state, there is an increase in the entropy of the system.

Increase in temperature or volume also results in increase in entropy.

For example, when solid melts to form liquid, entropy increases. Also, when liquid changes to gas, entropy of the system increases.

Based on the above transformations:

In conclusion, an increase in disorderliness of a system results in entropy increase.

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Answer:

9.9 x 10^-2 g*cm²/s²

Explanation:

9.9 × 10^-9 kg*m²/s² =    g*cm²/s²

1 kg*m²/s² = 1 joule(s)

1 g*cm²/s² = 1 erg(s)

britannica

1 kg = 1000g = 1x10^3 g

1 m²= 10000 cm² = 1x10^4 cm²

add the exponents 3 and 4 which = 7

-9 + 7 = -2

9.9 × 10^-9 kg*m²/s² = 9.9 x 10^-2 g*cm²/s²

Answer:

I don't know what the hell is going on with the this.

Answer:

0.271 M NO₃⁻

Explanation:

To find the molarity of the nitrate ion (NO₃⁻), you need to (1) convert grams to moles (via molar mass), then (2) convert moles Al(NO₃)₃ to moles NO₃⁻, then (3) convert mL to L, and then (4) calculate the molarity. When (Al(NO₃)₃) dissolves in water, it dissociates into 3 nitrate ions. The final answer should have 3 sig figs.

(Steps 1 + 2)

Molar Mass (Al(NO₃)₃): 26.982 g/mol + 3(14.007 g/mol) + 9(15.998 g/mol)

Molar Mass (Al(NO₃)₃): 212.985 g/mol

1 Al(NO₃)₃ = 1 Al³⁺ and 3 NO₃⁻

6.25 g Al(NO₃)₃            1 mole               3 moles NO₃⁻
-------------------------  x  -----------------  x   -----------------------  =  0.0880 moles NO₃⁻
                                    212.985 g         1 mole Al(NO₃)₃

(Steps 3 + 4)

325.0 mL / 1,000 = 0.3250 L

Molarity = moles / volume

Molarity = 0.0880 moles / 0.3250 L

Molarity = 0.271 M

Answer:

No it's correct.

Explanation:

The water temperature is 25 degrees Celsius. it's rigHT.

The answer is 6 nitrogen atoms.

The given chemical formula is : 3Zn(NO₃)₂

Let's find the number of nitrogen atoms by opening the bracket.

Hence, there are 6 nitrogen atoms.

The total energy released per gram of methane in the experiment is 119941.33 J/g

Change in temperature (ΔT) = T₂ – T₁

Change in temperature (ΔT) = 68 – 25

Change in temperature (ΔT) = 43 °C

The absorbed by the water can be obtained as illustrated below:

Q = MCΔT

Q = 500 × 4.184 × 43

Q = 89956 J

Heat absorbed by water = 30% of heat released by methane

89956 = 30% × heat released by methane

89956 = 0.3 × heat released by methane

Divide both sides by 0.3

Heat released by methane = 89956 / 0.3

Heat released by methane = 299853.33 J

Q = m × ΔH

Divide both sides by m

ΔH = Q / m

ΔH = 299853.33 / 2.5

ΔH =119941.33 J/g

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The events in the life of a star in the correct order is as follows: F, B, C, D, E and A.

The life of a star refers to the the events that occur in a star from when it formed newly until when it finally dies off.

When stars are newly formed, they are formed from star dust, and when just before they die, the form supernovas.

The several events in the life of a star can be arranged thus:

In conclusion, the life of a star is the period of its formation to its burning out or death.

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Note that the complete question is given below:

Arrange the events in the life of a star in the correct order.

A. All that remains of the star now is the core. In some cases, the star turns into a black hole

B. As the nuclear fusion sets off a chain reaction, the nebula gets hotter and brighter and turns into a star.

C. The star stays in the main sequence stage for a long time.

D. The star runs out of hydrogen and turns into a planetary nebula or a supernova, depending on its mass.

E. Heavy elements are created when the supernova explodes.

F. The temperature increases in the center of a nebula, and nuclei begin to fuse.

The best way to represent the concentration of a 1.75 M K2CrO4 solution is 1.75% K2CrO4 (option A).

Molarity is the concentration of a substance in solution, expressed as the number moles of solute per litre of solution.

The molarity is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solution.

The molarity is measured in mol/L or M, hence, it can be said that the molarity of a solution is 0.1M.

However, the concentration of a solution is best represented by using %. In accordance with this question, the best way to represent the concentration of a 1.75 M K2CrO4 solution is 1.75% K2CrO4.

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B. At the equivalence point of a titration of the [H+] concentration is equal to 7.

The equivalence point of a titration is a point in titration at which the amount of titrant added is just enough to completely neutralize the analyte solution.

At the equivalence point in an acid-base titration, moles of base equals moles of acid and the solution only contains salt and water.

At the equivalence point, equal amounts of H+ and OH- ions combines as shown below;

H⁺ + OH⁻  → H₂O

The pH of resulting solution is 7.0 (neutral).

Thus, the pH at the equivalence point for this titration will always be 7.0.

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Answer:

See below

Explanation:

45 kJ / gm   * .77  gm / liter  * 13 liter =  _________  kJ

Burning 13 L of gasoline would produce 450,450 kJ of energy. For calculating the amount of energy produced by burning 13 L of gasoline, we can use the given information that 1 gram of gasoline produces 45.0 kJ of energy when burned and the density of gasoline is 0.77 g/mL.

First, we need to convert the volume of gasoline from liters to milliliters since the density is given in grams per milliliter.

13 L = 13,000 mL

Next, we can calculate the mass of the gasoline using the density:

Mass = Volume x Density

Mass = 13,000 mL x 0.77 g/mL

Mass = 10,010 g

Now, we can calculate the amount of energy produced by multiplying the mass of gasoline by the energy produced per gram:

Energy = Mass x Energy per gram

Energy = 10,010 g x 45.0 kJ/g

Energy = 450,450 kJ

Therefore, burning 13 L of gasoline would produce 450,450 kJ of energy.

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Answer:

the water level remains the same when the ice melts

Answer:

Because then the shape that it would look would supposed to look like, would be different.

Explanation:

The balanced redox reaction equation is 2Fe^2+  (aq) + H2O2 (aq)+2H + (aq) → 2Fe^3+ (aq)+2e + 2H2O(l).

A redox reaction equation is one in which there is a loss or gain of electrons. We can see that the oxidation number of some species is increased while the oxidation number of some species is reduced.

The oxidation half equation is written as; 2Fe^2+  (aq)→2Fe^3+ (aq)+2e

The reduction half equation is written as; H2O2 (aq)+2H + (aq)+2e  →2H2O(l).

Thus, the overall balanced redox reaction equation is written as;

2Fe^2+  (aq) + H2O2 (aq)+2H + (aq) → 2Fe^3+ (aq)+2e + 2H2O(l).

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We can achieve equilibrium state, when the concentration of product and reactants are equal to each other.

In this type of system, when the same amount of liquid water is converted into gaseous form of water and the gaseous form of water into liquid form of water. This phase is known as equilibrium phase or state because same amount of reactants and products are produced .

So we can conclude that we can achieve equilibrium state, when the concentration of product and reactants are equal to each other.

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Answer:

9.25l

Explanation:

9.25l was correct answer

The ideal gas law is a fundamental equation that describes the behavior of an ideal gas. It relates the pressure (P), volume (V), temperature (T), and number of moles (n) of an ideal gas using the ideal gas constant (R). The volume of the gas is 18.5 L. Hence option D is correct.

We can use the ideal gas law to solve this problem:

PV = nRT

where:

P is the pressure of the gas (in atm)

V is the volume of the gas (in L)

n is the number of moles of the gas

R is the ideal gas constant (0.08206 L·atm/mol·K)

T is the temperature of the gas (in K)

Plugging in the values from the problem, we get:

2 atm * V = 1.5 mol * 0.08206 L·atm/mol·K * 300 K

V = (1.5 mol * 0.08206 L·atm/mol·K * 300 K) / 2 atm

V = 18.5 L

Therefore, the volume of the gas is 18.5 (option D).

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Answer:

The correct answer is A

Explanation:

Ionic compounds conduct electricity when molten (liquid) or in an aqueous solution because their ions are free to move from place to place

hope it will help you

hope it will help you

From the calculation, the correct statements are;

Now we know that it is possible to obtain the equilibrium constant from the relation;

E°cell = 0.0592/n log K

E°cell = cell potential = -0.403 - 0.535 = -0.938 V

n = number of electrons = 2 electrons

K = equilibrium constant

Thus;

-0.938 =  0.0592/2 logK

-0.938 * 2/ 0.0592 = log K

K = 2 * 10^-31

ΔG = - nFE°cell

ΔG = - (2 * 96500 *  -0.938)

ΔG = 181kJ/mol

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The answer is in scientific notation 34^67 42’063 1220.

The correct form for scientific notation is a x 10^b. where a is a number or decimal such that the absolute value of a is greater than or equal to 1 and less than 10, or 1 ≤ |a|. < 10. b is the power of 10 required to make the scientific notation mathematically equivalent to the original number.

To write this number in scientific notation, you must first shift the number of decimal places from the original number by 4 places between 4 and 2. We're subtracting from the exponent because we're shifting the decimal four places to the right.

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the rate of cooling decreases

Answer:

1.) [H⁺] = 2.69 x 10⁻⁹

2.) [H⁺] = 6.61 x 10⁻⁶

3.) [H⁺] = 5.01 x 10⁻²

Explanation:

The [H⁺] in a solution can be found using the following equation:

[H⁺] = 10^(-pH)

Therefore, you can plug the given pH into the equation and solve for the hydrogen ion concentration ([H⁺]).

1.) pH 8.57

[H⁺] = 10^(-pH)

[H⁺] = 10^(-8.57)

[H⁺] = 2.69 x 10⁻⁹

2.) pH 5.18

[H⁺] = 10^(-pH)

[H⁺] = 10^(-5.18)

[H⁺] = 6.61 x 10⁻⁶

3.) pH 1.30

[H⁺] = 10^(-pH)

[H⁺] = 10^(-1.30)

[H⁺] = 5.01 x 10⁻²

Taking into account the definition of molarity, the final sugar solution has a concentration of 5.028 M.

Molar concentration or molarity is a measure of the concentration of a solute in a solution and indicates the number of moles of solute that are dissolved in a given volume.

The molarity of a solution is calculated by dividing the moles of solute by the volume of the solution:

molarity= number of moles÷ volume

Molarity is expressed in units [tex]\frac{moles}{L}[/tex].

In this case, you mix 20.0 mL (0.02 L) of a 3.00 M sugar solution with 30.0 mL (0.03 L) of a 6.38 M sugar solution. To know the concentration of the sugar solution, you need to find the total moles of sugar solution from the mixtures as follow:

Now, the total volume of the solution is calculated adding the volume of the two solutions:

total volume= 20 mL + 30 mL= 50 mL= 0.05 L

Replacing the values inf the definition of molarity:

molarity= 0.2514 moles÷ 0.05 L

Solving:

molarity= 5.028 M

Finally, the final sugar solution has a concentration of 5.028 M.

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Answer:

23.55 L

Explanation:

USe the following 'identity' of gs laws

P1 V 1 / T1 = P2 V2 / T2         ( T must be in Kelvin)

re arrange to

P1 V 1  T2  /  (T1 P2)   = V2       NOW SUB IN THE VALUES

752 * 34.2 * ( 34 + 273.15) / [( 229 + 273.15) * 668]   = V2 = 23.55 L

Answer:

1st = saturated

Explanation:

Bro first ka answer saturated he