HELP ILL MARK BRAINLIEST
What makes a White Dwarf Star different from Main Sequence, Giant, and Supergiant stars?

Answer:

Work Done= Force×Displacement

Thus

Work Done = 20×10

Work Done = 200Joules

Barnacles are sessile/non-moving arthropods that attach to boats/whales. Sessile means they don't move and are fixed to a place.

A barnacle is an arthropod that belongs to the subclass Cirripedia of the subphylum Crustacea and is thus connected to crabs and lobsters. Barnacles are only found in the sea and prefer shallow and tidal seas, usually in erosive environments.

They play a vital part in the food chain since they are filtering organisms. Barnacles are suspension feeders, devouring plankton and dissolved debris floating in seawater, and hence play an important role in water purification for other creatures.

Barnacles produce thick calcium plates that surround them entirely. A white cone comprised of six calcium plates surrounds the crustacean.  Four more slabs form a "door" that the barnacle may open and close according on the tide. When the tide goes out, the barnacle goes into hibernation to retain moisture.

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The [H⁺] of the solution is 5.01 * 10⁶ M

The [OBr⁻] of the solution is 5.01 * 10⁶ M

The [HOBr] of the solution is 0.01 M

The H⁺ and OBr⁻ ions come from the dissociation of the weak acid HOBr.

The value of Ka is 2.51 * 10⁻⁹

The value of pKa is 5.6

The pH of a solution is the negative logarithm of the hydrogen ion concentration of a solution.

pH = - log [H⁺]

From the given data:

pH of the solution = 5.3

solving for [H⁺];

\([H^{+}] = 10^{-pH}\)

\([H^{+}] = 10^{-5.3}\)

[H⁺] = 5.01 * 10⁶ M

The equation of the dissociation of the weak acid, HOBr is given below:

HOBr (aq) ⇄ H⁺ (aq) + OBr⁻ (aq)

Moles of H⁺ (aq) = OBr⁻ (aq)

Therefore, [H⁺] = [OBr⁻]

[OBr⁻] = 5.01 * 10⁶ M

The acid dissociation constant, Ka, is calculated as follows:

Ka = [H⁺] * [OBr⁻] /  [HOBr]

where  [HOBr] = concentration of the weak acid, HOBr.

At equilibrium  [HOBr] >>>  [H⁺] and [OBr⁻]

[HOBr] = 0.010 M

Ka = (5.01 * 10⁶ M *  5.01 * 10⁶ M) / 0.010 M

Ka = 2.51 * 10⁻⁹

pKa = - log (Ka)

pKa = - log (2.51 * 10⁻⁹)

pKa = 5.6

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Answer:

Fluorine has a higher electronegativity than carbon

Explanation:

Electronegativity trend

-As you go from left to right across the periodic table, the electronegativity increases.

-As you go from top to bottom, the electronegativity decreases.

-We know that both carbon and fluorine are in the same energy level or period 2. However, Carbon is in group 14, which has 4 valence electrons, while fluorine is in group 17, which has 7 valence electrons. Therefore, fluorine has a higher electronegativity because fluorine is desperately wanted to gain 1 more valence electron to become stable (octet rule).

The rate constant of the second-order reaction is 0.111 M^-1 min^-1.

The given data represents a second-order reaction where the rate of the reaction is proportional to the square of the concentration of A.

The integrated form of the second-order reaction is:

1/[A]t = kt + 1/[A]0

where [A]t and [A]0 are the concentrations of reactant A at time t and time zero, respectively, k is the rate constant.

We can use the given information to calculate the rate constant (k) of the reaction for the given half-life (t1/2) of 3.15 minutes:

t1/2 = (1 / k[A]0)

Using the percentage decrease in concentration and the given initial concentration, we can calculate the concentration of A at time t:

[A]t = [A]0 - 0.30[A]0 = 0.57126 M

Substituting the given values, we get:

3.15 min = (1 / k)(0.0818 M) / (0.0818 M - 0.57126 M)

Simplifying the equation above, we can solve for k:

k = 0.111 M^-1 min^-1

Therefore, the rate constant of the second-order reaction is 0.111 M^-1 min^-1.

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Answer:

there are 6 MOLES of zinc nitrate in 145 g

Answer:

I think it's C.90º

Explanation:

Answer:

180o

Explanation:

It is 180 degrees because the central atom is the atom in the middle of two electrons. Think about it like a straight line, a straight line is equal to 180 degrees. One electron connected to the central atom will be 90 degrees and if there's another electron, it will be 180 degrees.

Hope this helps:)

This is probably wrong but i think the answer is 1,979,381.44

Forest Food web consists of the producers, main consumers, secondary consumers, scavengers, and decomposers. Food web is the collection of the large number of food chains.

Numerous food chains make up a food web. As animals seek food, a food chain only follows one way. As an example, a hawk consumes a snake following the consumption of a frog, a grasshopper, and grass. A food web illustrates the numerous relationships between plants and animals.

1. Primary consumers

2. Secondary consumers

3. Tertiary consumers

4. Decomposers or phytoremediators

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Answer:

the amount of water vapor in the air compared to the amount it can hold

Explanation:

By definition, relative humidity is equal to the partial pressure of water divided by the total amount of water that the air can hold at that temperature. The last one basically restates the definition. (Partial pressure is the number of particles of a substance divided by the total number of particles.)

(Have a nice day too! Don't hesitate to ask any questions)

KH2PO4 is a more suitable choice as a buffer because it has a greater buffering capacity due to the presence of the weak acid and its conjugate base.

KHPo4 is not considered an effective buffer compared to KH2PO4 due to its limited buffering capacity. The effectiveness of a buffer is determined by the concentration and dissociation properties of its conjugate acid-base pair.

KH2PO4 is a salt composed of the weak acid H2PO4- and its conjugate base HPO4^2-. In an aqueous solution, KH2PO4 can dissociate to release H+ ions from the H2PO4- component, which acts as a weak acid, and the HPO4^2- component can accept H+ ions, acting as a weak base. This allows KH2PO4 to effectively resist changes in pH when small amounts of acid or base are added to the solution.

On the other hand, KHPo4 consists of the strong acid H3PO4 and the weak base HPO4^2-. H3PO4 fully dissociates in water, providing a large concentration of H+ ions, making it difficult for the HPO4^2- to effectively act as a base and maintain pH stability.

Therefore, KH2PO4 is a more suitable choice as a buffer because it has a greater buffering capacity due to the presence of the weak acid and its conjugate base.

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In Experiment 1, we found the heat of solution of sodium hydroxide (NaOH) by dissolving 2.00 g of NaOH in 50.0 mL of water.

The temperature rose from 20°C to 28.5°C. The moles of NaOH were determined to be 0.0518 mol.

Using the specific heat of water (4.184 J/g°C), we calculated the enthalpy change (ΔH_sol) and compared it to the literature value, finding a percent error.

In Experiment 2, we measured the heat of neutralization between NaOH and 0.75 M HCl.

The temperature increased from 23.5°C to 27°C. We determined the moles of HCl, limiting reagent, and enthalpy change (ΔH_neut) for the neutralization reaction.

The actual value was compared to the literature value, and percent error was calculated.

Experimental errors in both experiments could arise from heat loss/gain, variations in room temperature and atmospheric pressure, and imprecise measurements.

The enthalpy changes in both experiments are due to bond breaking and forming during the dissociation of NaOH and the neutralization reaction between NaOH and HCl.

In conclusion, we determined the heat of solution for sodium hydroxide and the heat of neutralization between sodium hydroxide and hydrochloric acid, and analyzed the possible sources of experimental errors.

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Molarity of acid=2.5M

pH=5.1.

ka=?

Now

We need to write an eqn to show the dissociation of the acid

HA + H2O === H3O+ + A-

Writing The Equilibrium(Or Acid dissociation constant) of this reaction

Ka =[H3O+] {A-]/ {HA].

The concept behind this is

concentration of Products divided by those of reactants. Water is not written because its a pure liquid and does not affect the Equilibrium constant.

Now If you have any Idea on ICE tables..

You'd know that the concentration of acid will decrease by 2.5-x

Whilst the products...will increase by x each

Note: This is when the ratio of their Moles are in 1:1

ka= x.x/2.5-x

Since the Moles of A- and H3O+ are in 1:1... Their concentrations at equilibrium will be the same

so

Ka= x²/2.5-x

Now what is x??

x is the Hydrozonium ion concentration.

we can get it from the pH formula

pH= -log (H3O+)

Making H3O+ subject by applying Logarithm Rules

H3O+ = 10^-ph

x=10^-5.1

=7.94x10^-6.

Now back to Ka

Ka= x²/2.5-x

Ka= (7.94x10^-6)²/2.5-(7.94x10^-6)

Ka= (7.94x10^-6)²/2.4999

Ka= 2.52x10^-11.

Was a Fun One

The ionization constant of this weak acid is \(2.52*10^{-11}\). The values can be substituted in dissociation formula.

What information do we have?
Molarity of acid=2.5M

pH=5.1

To find:

ka=?

\(HA + H_2O < === > H_3O^+ + A^-\)

The value of dissociation constant will be:

\(Ka =[H_3O^+] [A^-]/ {HA]\)

The Moles of A- and H3O+ are in 1:1.Their concentrations at equilibrium will be the same.

\(Ka= x.x/2.5-x\\\\Ka= x^2/2.5-x\\\\pH= -log (H_3O^+)\\\\H_3O^+ = 10^{-pH}\\\\x=10^{-5.1}\\\\x=7.94*10^{-6}\)

\(Ka= x^2/2.5-x\\\\Ka= (7.94*10^{-6})^2/2.5-(7.94*10^{-6})\\\\Ka= (7.94*10^{-6})^2/2.4999\\\\Ka= 2.52*10^{-11}\\\\\)

Thus, ionization constant of this weak acid is \(2.52*10^{-11}\).

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ANSWER

The final volume of the gas is 0.29L

EXPLANATION

Given that

The initial volume of the gas is 1 liters

The initial pressure of the gas is 25mmHg

The final pressure of the gas is 85mmHg

Follow the steps below to find the final volume of the gas

Therefore, the final volume of the gas is 0.29L

1) Volume of oxygen gas produced is 3.19 L ; 2) Volume of gaseous HF produced is 4.92 L ; 3) Pressure of gaseous O₂ produced is 10.0 atm. ; 4) Pressure of gaseous B₂H₆ produced is 6292 mm Hg.5) 34.6 grams of phosphoric acid reacted.

Molar mass can be defined the mass of one mole of substance.

1.) Molar mass of potassium chlorate (KClO₃) is: 39.098 g/mol + 35.453 g/mol + 3 * 15.999 g/mol = 122.549 g/mol

10.5 g KClO₃ * (1 mol KClO₃ / 122.549 g KClO₃) * (3 mol O₂ / 2 mol KClO₃) = 0.1281 mol O₂

As V = (nRT) / P

= (0.1281 * 0.08206 * (25.0 + 273.15) ) / 1.05

So V = 3.19 L

Therefore, the volume of oxygen gas produced is 3.19 L.

2.) Molar mass of calcium fluoride (CaF₂) is: 40.078 g/mol + 2 * 18.998 g/mol = 78.076 g/mol

8.5 g CaF₂ * (1 mol CaF₂ / 78.076 g CaF₂) * (2 mol HF / 1 mol CaF₂) = 0.2171 mol HF

V = (0.2171  * 0.08206 / * 292.15 ) / 1.124

V = 4.92 L

Therefore, volume of gaseous HF produced is 4.92 L.

3.) Molar mass of HgO = 200.59 g/mol

125 g HgO = 125/200.59 = 0.623 mol HgO

From the balanced equation, 2 moles of HgO produces 1 mole of O₂

Therefore, 0.623 mol HgO produces 0.3115 mol O₂

As P = nRT/V

= (0.3115 mol)(0.08206 )(394.15 )/(9.61 )

P = 10.0 atm

Therefore, pressure of gaseous O₂ produced is 10.0 atm.

4. Molar mass of NaBH₄ = 37.83 g/mol

25.0 g NaBH₄ = 25.0/37.83 = 0.661 mol NaBH4

From the balanced equation, 2 moles of NaBH₄ produces 1 mole of B₂H₆

Therefore, 0.661 mol NaBH₄ produces 0.3305 mol  B₂H₆

As P = nRT/V

= (0.3305 )(0.08206 )(289.15 )/(8.10 )

P = 8.29 atm

8.29 atm = 6292 mm Hg

Therefore, pressure of gaseous  B₂H₆ produced is 6292 mm Hg.

5.) As n = PV/RT

n = (1.00 )(24.3 )/(0.0821 )(273 ) = 1.06 mol CO₂

1.06 mol CO₂ × (1 mol H₃PO₄/3 mol CO2) = 0.353 mol H₃PO₄

Molar mass of H₃PO₄ is 98.0 g/mol; so 0.353 mol H₃PO₄ × (98.0 g H₃PO₄/mol) = 34.6 g H₃PO₄

Therefore, 34.6 grams of phosphoric acid reacted.

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The molecules in a copper penny is closely packed and and has no space to move apart thus the material will be denser than that in the molten state. That's why the penny sink in the molten copper.

Copper is a transition metal exhibiting all the metallic properties. The molten state of metals is the fluid state where the molecule are not strongly held by the metallic bonds.

Molten material is made by melting them and the liquid like state contains molecules with some space to move apart. Whereas, in solid state as in a copper penny, the molecules are closely packed and have no space to move apart.

An object will sink in a liquid if it is less dense than the liquid. Copper penny is denser than the molten copper because the molecules are densely packed and it will sink on to it.

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Answer: The freezing point of a solution is the temperature at which the solution becomes a solid. The freezing point of a solution is lower than the freezing point of the pure solvent because the solute particles interfere with the movement of the solvent molecules, which slows down the freezing process.

To determine the freezing point of a solution, we can use the freezing point depression equation:

ΔTf = Kf x molality

where ΔTf is the change in freezing point, Kf is the freezing point depression constant for the solvent, and molality is the concentration of the solute in the solution expressed in moles of solute per kilogram of solvent.

To find the freezing point of a 0.520 m aqueous solution of NaCl (sodium chloride), we need to know the freezing point depression constant for water, which is 1.86 °C/m. We can then use the equation above to calculate the change in freezing point:

ΔTf = 1.86 °C/m x 0.520 m = 0.97 °C

To find the freezing point of the solution, we need to subtract the change in freezing point from the freezing point of the pure solvent. The freezing point of pure water is 0 °C, so the freezing point of the 0.520 m aqueous solution of NaCl is:

0 °C - 0.97 °C = -0.97 °C

Answer:

-1.934

Explanation:

0 - {(0.520) x (1.86) x (2)}

Flow sheet for synthesis gas production process: Hydrocarbon preheater → Combustion chamber Reactor → Waste-heat boiler → Carbon removal unit → water-cooler scrubber → Synthesis Gas.

Temperature and Pressure Conditions:

Hydrocarbon Preheater: High temperature (depends on the specific hydrocarbon used)

Combustion Chamber: High temperature (due to controlled partial combustion)

Reactor: High temperature (to promote pyrolysis and gas formation)

Waste-heat Boiler: Moderate temperature (to recover heat from reactor effluent)

Carbon-Removal Unit: Moderate temperature (to remove carbon from gas)

Water Cooler-Scrubber: Low temperature (to cool and scrub the gas)

Synthesis Gas: At atmospheric pressure (or specified process pressure).

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5998kJ

Given the reaction between ethanol and oxygen expressed as:

For the product

We have 2 moles of CO2 and 3 moles of water. The total bond energy in the product is expressed as:

Hence the total energy transferred to build all the bond energy in the product is 5998kJ

Once the roller coaster train gets closer to the bottom of the hill, its kinetic energy increases to 1,100 J, and its potential energy decreases to zero.

Potential energy is a type of energy that is stored and depends upon the relative height of system. If its height is increased, the potential energy is also increases while on the other hand, if the body comes to the surface of the earth, its potential energy will be zero due to no height of the object. We know that potential energy is equals to product of mass, gravity and height of an object.

So we can conclude that if the roller coaster train gets closer to the bottom of the hill, its kinetic energy increases to 1,100 J, and its potential energy decreases to zero.

Answer:

I think C

Explanation:

because hydrogen on the right side only have two while on the left side it have 4

Answer:

The answer is A. No Oxygen is Unbalanced

Explanation:

I took the test. You got this.

Answer:

cell sap :)

Explanation:

Answer:

well

Explanation:

Answer:

The molecular formula for sulfur hexafluoride is SF6 S F 6 , in which there is 1 sulfur atom and 6 fluorine atoms.

Explanation:

hope this helps

Answer:

B) hydraulics

Explanation:

Answer:

hydraulics

Explanation:

i got it right the test on apex

:DDDDDDDD

Answer: Formula:

pH=−log[H

+

]

when pH=4

[H

+

]=10

−pH

=10

−4

when pH=2

[H

+

]=10

−pH

=10

−2

The mass of CO₂ that would be required to react with 84.6g of LiOH in the following reaction would be 77.5g

According to the given reaction,

CO₂(g) + 2LiOH(g) --- Li₂CO₃ + H₂O(g)

? (84.6g)

As we know,

(mole of CO₂/coefficient) = (mole of LiOH/coefficient)

mole of CO₂/1 = (84.6/Molecular weight÷2)

(mass of CO₂/molecular weight of CO₂) = (84.6/molecular weight of LiOH÷2)

mass of CO₂/44 = 84.6/48

mass of CO₂ = 77.5g

Therefore, mass of CO₂ = 77.5g

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Answer

The final volume, V₂ the gas occupies = 8.81 L

Explanation

Given data:

Initial temperature, T₁ = 31 °C = 31 +273 K = 304 K

Initial volume, V₁ = 7.74 L

Final temperature, T₂ = 73 °C = 73 + 273 K = 346 K

Note: The pressure is kept constant.

What to find:

The final volume, V₂ the gas occupies.

Step-by-step solution

Using Charle's law:

To get V₂, substitute the given parameters into the equation above:

The final volume, V₂ the gas occupies is 8.81 L

There are approximately 0.0078 moles of molybdenum present in 0.75 grams.

In order to determine the number of moles of molybdenum present in 0.75 grams, we first need to know the molar mass of molybdenum. The molar mass of molybdenum (Mo) is 95.94 g/mol.

Next, we can use the formula:

moles = mass ÷ molar mass

Plugging in the given values, we get:

moles = 0.75 g ÷ 95.94 g/mol

Simplifying this expression, we get:

moles = 0.0078 mol

Therefore, there are approximately 0.0078 moles of molybdenum present in 0.75 grams.

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