What is the ph of a soft drink in which the major buffer ingredients are 6.6 g of nah2po4 and 8.0 g of na2hpo4 per 355 ml of solution?

Answers

Answer 1
The Relative Formula Mass of NaH2PO4 is 120 g/mol
Therefore, the number of moles = 6.6/120
                                                   = 0.055 moles of NaH2PO4 which is also equal to the number of moles of H2PO4.
[H2PO4-] = Number of moles oof H2PO4-/Volume of the solution in L
  = 0.055/ ( 355 ×10^-3)
  = 0.155 M
Na2HPO4 undergoes complete dissociation as follows;
Na2HPO4 (aq)= 2Na+ (aq) + HPO4^2- (aq)

1 mole of Na2HPO4 = 142 g/mol
Therefore; number of moles = 8.0/142
                                             = 0.0563 moles
 [HPO4 ^-2] is given by no of moles HPO4^2- /volume of the solution in L
     = 0.0563/(355×10^-3)
     =  0.1586 M
Both H2PO4^2- and HPO4^2- are weak acids the undergoes partial dissociation 
Ka of H2PO4- = 6.20 × 10^-8
 [H+] =Ka*([H2PO4-]/[HPO4(2-)]
        = (6.20 ×10^-8)×(0.155/0.1586)
        = 6.059 ×10^-8 M
pH = - log[H+]
     = - log (6.059×10^-8)
     = 7.218

Answer 2

pH is the estimation of the acidity and the basicity of the solution. The pH of the soft drink with buffer ingredients will be 7.218.

What is pH?

pH is the negative logarithm of the hydrogen ion concentration in an aqueous solution.

Moles of sodium dihydrogen phosphate is calculated as:

[tex]\begin{aligned}\rm moles &= \dfrac{6.6}{120} \\\\&= 0.055 \;\rm moles \end{aligned}[/tex]

The molar concentration of dihydrogen phosphate is calculated as,

[tex]\begin{aligned} &= \dfrac{\text{Moles of dihydrogen phosphate}}{\text {Volume }}\\\\&= \dfrac{0.055}{355 \times 10^{-3}}\\\\&= 0.155 \;\rm M\end{aligned}[/tex]

The complete dissociation of monosodium phosphate can be shown as,

[tex]\rm Na_[2}HPO_{4} (aq) \rightarrow 2Na^{+} (aq) + HPO_{4}^{2-} (aq)[/tex]

When 1 mole of monosodium phosphate = 142 g/mol

Then, moles =  0.0563 moles

The molar concentration of dihydrogen phosphate will be:

[tex]\begin{aligned} &= \dfrac{0.0563}{( 355 \times 10^{-3})}\\\\&= 0.1586\;\rm M\end{aligned}[/tex]

The partial dissociation of both the weak acid is given as:

[tex]\begin{aligned}\rm [H^{+}] &= \rm Ka \times \dfrac{([H_{2}PO_{4}^{-}]}{[HPO_{4}^{2-}]}\\\\ &= (6.20 \times 10^{-8}) \times (\dfrac{0.155}{0.1586})\\\\ &= 6.059 \times 10^{-8}\;\rm M \end{aligned}[/tex]

pH can be calculated as:

[tex]\begin{aligned} \rm pH &= \rm - log[H^{+}]\\\\ &= \rm - log (6.059 \times 10^ {-8})\\\\ & = 7.218\end{aligned}[/tex]

Therefore, 7.218 is the pH.

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Related Questions

which of these stars is least likely to be categorized as a supergiant? A. Betelgeuse B. Pollux C. Sirius A D. Sun Reset Submit

Answers

Answer: The correct answer is option D.

Explanation: Super-giant stars are the stars which are greater than Sun. They have a mass hundred time greater than Sun and can be thousand times greater than Sun.

The masses of the stars are represented in Solar masses which is the mass of the Sun.

Mass of Betelgeuse = 20 Solar masses

Mass of Pollux = 1.7 Solar masses

Mass of Sirius = 2.02 Solar masses

Mass of Sun = 1 Solar mass.

As, the mass of Sun is the least from the given stars. Hence, it is least considered as a super-giant.

Final answer:

Pollux is the least likely to be categorized as a supergiant since it is an evolved giant star, while Betelgeuse is a known red supergiant, and both Sirius A and the Sun are main-sequence stars.

Explanation:

The star least likely to be categorized as a super giant among the options provided is Pollux. Betelgeuse is a well-known red super giant that is visible near Orion's belt as the bright red star marking the hunter's shoulder. Pollux, in contrast, is classified as an evolved giant star (a red giant), which is a less massive and less luminous stage compared to a super giant. Option B

Sirius A, known for being the brightest star in the sky after the Sun, is a main-sequence star, and also not a super giant. The Sun itself is a main-sequence star, not nearly massive enough to ever become a super giant. Therefore, while neither Pollux, Sirius A, nor the Sun are super giants, Pollux being an evolved giant is the furthest in its life cycle from the super giant category compared to the main-sequence state of Sirius A and the Sun.

A student is told that both energy and mass must be conserved in every chemical reaction. She measures the mass of Hydrochloric acid and a zinc strip separately. She then places the zinc strip into the acid and bubbles form as the zinc looks like it disappears. The combined mass afterward is less than the original. Which of these can explain this result? A) The student must have not measured the mass correctly. B) The zinc disappears and therefore the mass is less after the reaction. C) This is not a chemical reaction so the conservation laws do not apply. D) The bubbles indicate that a gas is created and mass is loss as it escapes from the container.

Answers

Hello!

The statement that can explain the result is The bubbles indicate that a gas is created and mass is lost as it escapes from the container.

The reaction between Hydrochloric Acid and a Zinc Strip is the following one:

2HCl (aq) + Zn (s)→ ZnCl₂(aq) + H₂(g)

The bubbles that the student sees are caused by the Hydrogen gas that is being formed in the reaction. If the container isn't hermetically sealed, the gas will escape the solution and the final mass will be lower than the original. However, if the container is sealed, measuring the final mass will prove the Law of Conservation of Mass.

Have a nice day!
the bubbles indicate that a gas is being created therefore d is you answer

Help please? Will give brainliest...!!!!!!!

Answers

the answer would be A

Which defines reaction mechanism in chemistry? the mixing of two or more liquids to form a solution the steps in a chemical reaction in which products result from reactants a process in which a product is changed from one physical form to another intermolecular forces that cause attraction or repulsion between nearby particles?

Answers

Answer is: the steps in a chemical reaction in which products result from reactants.
Reaction mechanism tries to describe in detail what is happening at each stage of an overall chemical reactions (the step by step sequence of elementary reactions, this step are not usually observable) and order in which molecules react.

Answer:

the answer is B : the steps in a chemical reaction in which products result from reactants

Explanation:

can someone please help. A sucrose solution is prepared to a final concentration of 0.170M . Convert this value into terms of g/L, molality, and mass % (molecular weight, MWsucrose = 342.296g/mol ; density, ρsol′n = 1.02g/mL ; mass of water, mwat = 961.8g ). Note that the mass of solute is included in the density of the solution,

Answers

From Molarity: we have 0.17 mole sucrose in 1 Liter solution
1) To convert it into g/L we have to multiply moles of sucrose by its molar mass:
= 0.17 mole sucrose x [tex] \frac{342.296 g sucrose}{1 mole sucrose} [/tex] = 58.2 g/L
2) Molality =  number of moles of solute / mass in kg of solvent = [tex] \frac{0.17 mole solute}{0.9618 kg solvent} [/tex] = 0.177 mole / kg
3) mass % = mass of solute / mass of solution x 100 
mass of solution = 1020 g from its density
mass of solute = 1020 - 961.8 = 58.2 g solute
mass % = [tex] \frac{58.2 g solute}{1020 g solution} [/tex] x 100 = 5.7 %

which atoms exist as diatomic molecules?

Answers

If the diatomic molecule consists of atoms from two different elements, then it is aheteronuclear diatomic molecule. There are seven elements that naturally occur as homonucleardiatomic molecules in their gaseous states: hydrogen,nitrogen, oxygen, fluorine,chlorine, bromine, and iodine

At STP, two 5.0-gram solid samples of different ionic compounds have the same density. These solid samples could be dominated by their

Answers

Missing question:
1) mass.   
2) volume.
3) temperature.
4) solubility in water.
Answer is: 4) solubility in water.
This ionic solids can not be differentiated by mass, because they have same mass (5 g), neither by volume because they have same mass and density, than either and volume (d = m/V), solubility of compound is differente because different ions.

The correct answer is option (b).  At STP, two 5.0-gram solid samples of different ionic compounds have the same density. These solid samples could be dominated by their crystal structures.

A) Molar masses: The molar mass of a compound refers to the mass of one mole of that substance. While the molar mass affects the mass of the compound, it does not directly determine the density unless the volume occupied by the same mass of different compounds is considered.

B) Crystal structures: The crystal structure refers to the arrangement of ions in a solid. If two ionic compounds have the same density, it is likely that their ions are packed in a similar manner, resulting in the same volume for the same mass. The crystal structure determines how closely the ions are packed together, which directly influences the density.

C) Ionic charges: While ionic charges influence the electrostatic forces between ions, they do not directly determine the density of a solid. The arrangement of ions (crystal structure) has a more direct impact on density than the charges of the ions themselves.

D) **Solubilities**: The solubility of a compound refers to how well it dissolves in a solvent, such as water. This property does not affect the density of the solid form of the compound.

The complete question is:

At STP, two 5.0-gram solid samples of different ionic compounds have the same density. These solid samples could be dominated by their __________.

A) molar masses  

B) crystal structures  

C) ionic charges  

D) solubilities  

Which property could be a dominant factor for these solid samples to have the same density?

what is a saturated solution in your own words, please!!!!

Answers

It is a solution where a solute cannot dissolve anymore into the solvent.

Answer:

A saturated solution is a solution that has the maximum amount of solute that is capable of being dissolved

Explanation:

1. What mass of H2O will be produced if 9.5 g of H2 reacts with 1.2 g of O2?

__ H2 + __ O2 --> __ H2O

2. If 1.85 g of Mg(OH)2 reacts with 3.71 g of HCl, how much MgCl2 is produced? What is the limiting reactant?

__ Mg(OH)2 + __ HCl --> __ MgCl2 + __ H2O

3. What mass of potassium hydroxide is formed when 8.2 g of potassium oxide is added to 1.3 g of water?

__ K2O + __ H2O --> __ KOH

4. What mass of aluminum chloride could be made from 8.1 g of aluminum and 4.2 L of chlorine at STP?

__ Al + __ Cl2 --> __ AlCl3


I know this is a lot of questions but please help and show your work. Thank you.

Answers

This is the number 3..

1) The answer is: mass of water is 1.35 grams.

Balanced chemical reaction: 2H₂ + O₂ → 2H₂O.

m(O₂) = 1.2 g; mass of oxygen.

M(O₂) = 2 · 16 g/mol.

M = 32 g/mol, molar mass of oxygen.

n(O₂) = m(O₂) ÷ M(O₂).

n(O₂) = 1.2 g ÷ 32 g/mol.

n(O₂) = 0.0375 mol; amount of oxygen, limiting reactant.

m(H₂) = 9.5 g; mass of hydrogen.

M(H₂) = 2 g/mol, molar mass of hydrogen.

n(H₂) = m(H₂) ÷ M(H₂).

n(H₂) = 9.5 g ÷ 2 g/mol.

n(H₂) = 4.5 mol; amount of hydrogen.

From chemical reaction: n(O₂) : n(H₂O) = 1 : 2.

n(H₂O) = 0.0375 mol · 2.

n(H₂O) = 0.075 mol; amount of water.

m(H₂O) = n(H₂O) · M(H₂O).

m(H₂O) = 0.075 mol · 18 g/mol.

m(H₂O) = 1.35 g; mass of water.

2) The answer is: 3.05 grams of MgCl₂ is produced, the limiting reactant is Mg(OH)₂.

Balanced chemical reaction: 2HCl + Mg(OH)₂ → MgCl₂ + 2H₂O.

m(Mg(OH)₂) = 1.85 g; mass of magnesium hydroxide

n(Mg(OH)₂) = m(Mg(OH)₂) ÷ M(Mg(OH)₂).

n(Mg(OH)₂) = 1.85 g ÷ 58.32 g/mol.

n(Mg(OH)₂) = 0.032 mol; limiting reactant.

m(HCl) = 3.71 g; mass of hydrochloric acid.

n(HCl) = 3.71 g ÷ 36.46 g/mol.

n(HCl) = 0.102 mol; amount of hydrochloric acid.

From chemical reaction: n(Mg(OH)₂) : n(MgCl₂) = 1 : 1.

n(MgCl₂) =0.032 mol; amount of magnesium chloride.

m(MgCl₂) = n(MgCl₂) · M(MgCl₂).

m(MgCl₂) = 0.032 mol · 95.21 g/mol.

m(MgCl₂) = 3.05 g; mass of magnesium chloride.

3) The answer is: mass of potassium hydroxide is 8.1 grams.

Balanced chemical reaction: K₂O + H₂O → 2KOH.

m(K₂O) = 8.2 g; mass of potassium oxide.

n(K₂O) = m(K₂O) ÷ M(K₂O).

n(K₂O) = 8.2 g ÷ 94.2 g/mol.

n(K₂O) = 0.087 mol; amount of potassium oxide.

m(H₂O) = 1.3 g; mass of water.

n(H₂O) = 1.3 g ÷ 18 g/mol.

n(H₂O) = 0.072 mol; limiting reactant.

From chemical reaction: n(H₂O) : n(KOH) = 1 : 2.

n(KOH) = 2 · 0.072 mol.

n(KOH) = 0.144 mol.

m(KOH) = 0.144 mol · 56.1 g/mol.

m(KOH) = 8.1 g; mass of potassium hydroxide.

4) The answer is: mass of aluminum chloride is 16.66 grams.

Balanced chemical reaction: 2Al + 3Cl₂ → 2AlCl₃.

m(Al) = 8.1 g; mass of aluminium.

n(Al) = m(Al) ÷ M(Al).

n(Al) = 8.1 g ÷ 27 g/mol.

n(Al) = 0.3 mol.

V(Cl₂) = 4.2 L; volume of chlorine.

n(Cl₂) = 4.2 L ÷ 22.4 L/mol.

n(Cl₂) = 0.1875 mol; limiting reactant.

From chemical reaction: n(Cl₂) : n(AlCl₃) = 3 : 2.

n(AlCl₃) = 2 · 0.1875 mol ÷ 3.

n(AlCl₃) = 0.125 mol; amount of aluminium chloride.

m(AlCl₃) = 0.125 mol · 133.34 g/mol.

m(AlCl₃) = 16.66 g; mass of aluminium chloride.

How many molecules (not moles) of nh3 are produced from 5.81×10−4 g of h2? express your answer numerically as the number of molecules?

Answers

the reaction of formation of NH₃ is as follows;
N₂ + 3H₂ ---> 2NH₃
the stoichiometry of H₂ to NH₃ is 3:2
for every 3 moles of H₂ that reacts, 2 moles of NH₃ are produced 
the mass of H₂ that has been used up = 5.81 x 10⁻⁴ g 
molar mass of H₂ = 2 g/mol
number of H₂ moles that were used up = 5.81 x 10⁻⁴ g/ 2 g/mol
                                                              = 2.905 x 10⁻⁴ mol
for every 3 mol of H₂ used up - 2 moles of NH₃
for every 1 mol of H₂ used up - 2/3 moles of NH₃
therefore for 2.905 x 10⁻⁴ mol of H₂ = 2/3 x 2.905 x 10⁻⁴ mol 
number of NH₃ moles produced = 1.94 x 10⁻⁴ mol
number of NH₃ molecules in 1 mole = 6.022 x 10²³ molecules 
therefore in 1.94 x 10⁻⁴ mol  = 6.022 x 10²³ molecules/mole x 1.94 x 10⁻⁴ mol

therefore number of NH₃ molecules produced = 1.168 x 10²⁰ NH₃ molecules  

Sirius is a blue-white star with a surface temperature of about 9800 K. What is most likely the mass of Sirius? 1.0 solar mass 1.4 solar mass 2.0 solar mass 12 solar mass

Answers

1.4 solar mass should be the answer.

The answer is actually 2.0 solar masses.

Will medal!!!
The addition of hydrochloric acid to a silver nitrate solution precipitates silver chloride according to the reaction:
AgNO3(aq)+HCl(aq)→AgCl(s)+HNO3(aq)
When you combine 70.0mL of 0.185M AgNO3 with 70.0mL of 0.185M HCl in a coffee-cup calorimeter, the temperature changes from 23.16∘C to 24.25∘C.
Calculate ΔHrxn for the reaction as written. Use 1.00 g/mL as the density of the solution and C=4.18J/g⋅∘C as the specific heat capacity.,

Answers

Δ H reaction = q / n where q: amount of heat released and n is number of moles of substance.
q = m . C . ΔT where:
m = mass of substance (g)
C = Specific heat capacity (4.18)
ΔT = change in temperature = 24.25 - 23.16 = 1.09
q = 1000 x 4.18 x 1.09 = 4556 J = 4.556 kJ
number of moles (n) = Molarity (M) x Volume (L)
                                 = 0.185 M x 0.07 L = 0.01295 mole
Δ H = q / n = - (4.556 kJ / 0.01295 mole) = -351.8 kJ / mol
Note: it is exothermic reaction (-ve sign)  i.e. temperature is raised

The diagram shows Niels Bohr’s model of an atom.


What happens when the electron moves from the first energy level to the second energy level?
Energy is absorbed, and an emission line is produced.
Energy is released, and an emission line is produced.[wrong]
Energy is absorbed by the atom.
Energy is lost from the atom.

Answers

when the electrons are jumped from low to high energy level, energy is absorbed making them able to jump to a higher state. it cant be emission line produce because that's when energy is released but in this case, it's being absorbed. I would go with "energy is absorbed by the atom"

Answer: When the electron moves from the first energy level to the second energy level, energy is absorbed.

Explanation:

When an electron moves from first energy level to the second energy level,energy is being absorbed by the atom which means that the electron jumps from lower energy level to higher energy level.

Bohr's Equation

E=[tex]\frac{-E_0}{n^2}[/tex]

where,

E= energy of an  electron in 'n' level (n=1,2,3...etc)

[tex]E_0[/tex]= energy of an electron in ground state.

as we can see from this equation energy is inversely proportional to the n principle quantum number which means that there will be decrease in energy. As the energy is decreasing in magnitude with the negative sign  which actually means there is increase in energy.

How can you determine the number of moles of a contained gas when the pressure, volume, and temperature are known values?

Answers

Answer: use the ideal gas equation, PV = nRT

Explanation:

The ideal gas equation permits you to determine one variable, P, V, n or T, when you know the other two variables.

In this case, your are told you know P, V and T, so you can solve for n:

n = PV / (RT)

Remember this:

R is the universal constant of gases, and you must use the adequate units.

T is the temperature in absolute scales, i.e Kelvin.

Under STP conditions (1 atm and 0°C), 1 mole of an ideal gas occupies 22.4 liters.

The Ideal Gas Law is a fundamental equation that relates the pressure (P), volume (V), and temperature (T) of an ideal gas to the number of moles (n) of the gas. The law is expressed by the equation:

[tex]\[ PV = nRT \][/tex]

where:

- [tex]P[/tex] is the pressure of the gas, typically measured in atmospheres (atm),

- [tex]V[/tex] is the volume of the gas, usually measured in liters (L),

- [tex]n[/tex] is the number of moles of the gas,

- [tex]\( R \)[/tex] is the ideal gas constant, which has a value of 0.0821 L·atm/(mol·K) when the pressure is in atm and the volume is in liters, and

- [tex]\( T \)[/tex] is the temperature of the gas in Kelvin (K).

To find the number of moles [tex]n[/tex], we can rearrange the Ideal Gas Law equation to solve for [tex]n:[/tex]

[tex]\[ n = \frac{PV}{RT} \][/tex]

For example, if we have a gas at a pressure of 1 atm, a volume of 22.4 L (which is the molar volume of an ideal gas at STP), and a temperature of 273 K (0°C), we can calculate the number of moles as follows:

[tex]\[ n = \frac{(1 \text{ atm})(22.4 \text{ L})}{(0.0821 \text{ L·atm/(mol·K)})(273 \text{ K})} \][/tex]

[tex]\[ n = \frac{22.4}{0.0821 \times 273} \][/tex]

[tex]\[ n \approx 1 \text{ mol} \][/tex]

This calculation confirms that under STP conditions (1 atm and 0°C), 1 mole of an ideal gas occupies 22.4 liters.

The equilibrium constant kc for the decomposition of phosgene, cocl2, is 4.63 10-3 at 527°c. cocl2(g) equilibrium reaction arrow co(g) + cl2(g) calculate the equilibrium partial pressure of all the components, starting with pure phosgene at 0.760 atm.

Answers

Final answer:

To determine the equilibrium partial pressures for the components of phosgene decomposition, we first establish the initial conditions and use the given equilibrium constant. We then set up an equation based on the changes at equilibrium and solve it to find the equilibrium partial pressures.

Explanation:Equilibrium Partial Pressure of Phosgene Decomposition Components

The decomposition of phosgene (COCl2) into carbon monoxide (CO) and chlorine gas (Cl2) can be observed using the equation COCl2(g) ⇌ CO(g) + Cl2(g). From the problem, we can consider an initial pressure of 0.760 atm of COCl2 and a negligible amount of CO and Cl2. Given that the equilibrium constant (Kc) for this reaction is 4.63 x 10-3, we can set up an equation derived from the equilibrium expression: Kc = (PCO x PCl2)/PCOCl2.

As the reaction proceeds, the pressure of COCl2 decreases by an 'x' amount to establish equilibrium, and the pressure of CO and Cl2 increases by the same 'x' amount. Thus, at equilibrium: Kc = ((0.760-x)x)/x. Solving this equation for 'x', we can obtain the equilibrium partial pressure of all components in the system.

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MEDAL, please help me understand.
Which best describes the oxidizing agent in this reaction?
Cl2(aq) + 2Brmc003-1.jpg(aq) mc003-2.jpg 2Clmc003-3.jpg(aq) + Br2(aq)
Bromine (Br) is the oxidizing agent because it gains an electron.
Bromine (Br) is the oxidizing agent because it loses an electron.
Chlorine (Cl) is the oxidizing agent because it gains an electron.
Chlorine (Cl) is the oxidizing agent because it loses an electron.,

Answers

The equation is:
Cl₂(aq) + 2 Br⁻(aq) → 2 Cl⁻ (aq) + Br₂(aq)
Oxidation = Loss of electrons
Reduction = gaining of electrons
Oxidizing agent : gain electrons and reduced
Reducing agent : lose electrons and oxidized
For Cl₂ it converted to 2 Cl⁻ so it gains electrons (Reduced) so it oxidize Br⁻ so it considered as Oxidizing agent
So the correct answer is:
C. Chlorine (Cl) is the oxidizing agent because it gains an electron

Answer:

c

Explanation:

How many protons, neutrons, and electrons are in a neutral atom with the symbol 41Ca
A) 20 protons, 21 neutrons, 21 electrons
B) 20 protons, 21 neutrons, 20 electrons
C) 21 protons, 21 neutrons, 20 electrons
D) 41 protons, 0 neutrons, 41 electrons

Answers

B  the atomic number is 20 and then you subtract atomic mass to find the neutrons

There are 20 protons, 21 neutrons,20 electrons are in a neutral atom with the symbol 41Ca.

Explanation:

Given:

The neutral atom with symbol 41Ca

To find:

The numbers of protons, neutrons, and electrons.

Solution:

The given symbol of an atom is Ca which means that the given atom is of calcium.

The atomic number of calcium = 20

The atomic number of atom = Number of protons in an atom

The number of proton in a given calcium atom = 20

The given atom is neutral which means that an equal number of protons and electrons will be present.

The number of electrons = Number of protons = 20

The number of electrons in a given calcium atom = 20

The mass number of an atom is a sum of the number of neutrons and the number of protons

The number of neutrons = n

In the given symbol of calcium atom, the mass number of calcium is also given which is 41.

The mass number of the calcium atom = 41

[tex]41=n+20\\n=41-20=21[/tex]

The number of neutrons = 21

The number of neutrons in a given calcium atom = 21

There are 20 protons, 21 neutrons,20 electrons are in a neutral atom with the symbol 41Ca.

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Determine the entropy change when 1.80 mol of HBr(g) condenses at atmospheric pressure?

Answers

Answer:

Entropy change = -168.3 J/mol-K

Explanation:

The entropy change is expressed as:

[tex]DeltaS = \frac{DeltaH}{T}[/tex]

For HBr, the enthalpy of condensation = -19.27 kJ/mol

Temperature T = -67 C = 273 - 67 = 206 K

Therefore, the entropy change when 1 mol of HBr condenses is:

= [tex]\frac{-19.27 kJ/mol}{206 K} =0.0935 kJ/mol-K = -93.5 J/mol-K[/tex]

Thus for the given 1.80 mol of HBr the entropy change would be:

[tex]= 1.80 mol * -93.5 J/mol- K = -168.3 J/mol-K[/tex]

Final answer:

The entropy change when 1.80 mol of HBr(g) condenses at atmospheric pressure can be determined using the equation ΔS = -ΔH/T, where ΔH is the enthalpy change and T is the temperature.

Explanation:

The entropy change when a substance condenses can be calculated using the following equation:

∆S = -∆Hvap / T

where:

∆S is the entropy change (J/K·mol)

∆Hvap is the enthalpy of vaporization (kJ/mol)

T is the temperature of condensation (K)

The enthalpy of vaporization of HBr is -19.27 kJ/mol. The temperature at which HBr condenses at atmospheric pressure is its boiling point, which is -67°C. Converting this temperature to Kelvin, we get:

T = -67°C + 273.15 K = 206.15 K

Plugging in these values, we get:

∆S = -(-19.27 kJ/mol) / 206.15 K = 0.09348 kJ/K·mol

Converting kJ to J, we get:

∆S = 0.09348 kJ/K·mol * 1000 J/kJ = 93.48 J/K·mol

Therefore, the entropy change when 1.80 mol of HBr(g) condenses at atmospheric pressure is -168.3 J/K·mol.

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Which of the following radioisotopes is naturally occurring?

93^239Np

53^131I

102^254No

96^242Cm

Answers

The answer is 53^131I.

This is a radioisotope of iodine. It also has a radioactive half life decay of about 8 days.

Answer:

I - 131 is the correct answer.

I - 131 is the only naturally occuring radioactive isotope among these four options.

Explanation:

Np - 239 - Neptunium is also considered as an artificial element,as only trace amounts of it are found in nature.

And Np - 239 is not a naturally occuring radioactive isotope but it is synthesized artificially.

No - This is an artificial element.That means its not found in nature. Hence all its isotopes are also synthesized artificially.

Cm - This is also an artificial element and all its isotopes are also synthesized artificially.

Np - 239,No - 254,Cm - 242 are radioactive isotopes but they are not naturally occuring radioactive isotopes. But these three are artificially made radioactive isotopes.

And Iodine - 131 is the only naturally occuring radioisotope among these.

The solubility of a gas in a liquid is _____. proportional to the square root of the pressure of the gas above the liquid unrelated to the pressure of the gas above the liquid inversely proportional to the pressure of the gas above the liquid directly proportional to the pressure of the gas above the liquid

Answers

Answer:

directly proportional to the pressure of the gas above the liquid

Explanation:

Henry’s law,

Sg = k Pg

where Sg, k and Pg are solubility of the gas, Henry’s constant and partial pressure of the gas respectively.  

According to Henry’s law the amount of gas that can dissolve in a liquid is directly proportional to the partial pressure of the gas above the liquid.  

What is the balanced chemical equation for the reaction used to calculate ΔH∘f of SrCO3(s)?
If fractional coefficients are required, enter them as a fraction (i.e. 1/3). Indicate the physical states using the abbreviation (s), (l), or (g) for solid, liquid, or gas, respectively without indicating allotropes. Use (aq) for aqueous solution.

Answers

Based on your problem above, we have to balance the equation in order to get the product.
From your given, ΔH∘f of SrCO3(s)
The balanced equation is:
Sr(s) + C(s) + 3/2 O2(g) -> SrCO3(s)

Answer:

[tex]Sr(s)+C(s)+ 3/2O_{2}(g)\rightarrow SrCO_{3}(s)[/tex]

Explanation:

The standard enthalpy of formation (ΔH°f) is defined as the enthalpy change which accompanies the formation of 1 mole of a compound from its constituent elements all of which are in their standard states i.e. either solid (s), liquid (l) , gas (g) or the aqueous phase (aq).

Strontium carbonate (SrCO3) contains 3 elements:

-Strontium (Sr) where the standard state is solid(s)

- Carbon (C) where the standard state is again a solid (s)

- oxygen (O) where the standard state is the gas phase (g)

The balanced chemical equation for the standard enthalpy of formation (ΔH°f) for SrCO3 would be:

[tex]Sr(s)+C(s)+ 3/2O_{2}(g)\rightarrow SrCO_{3}(s)[/tex]

What is the most important requirement for all living things? water carbon dioxide light vitamins

Answers

Water. All organisms that depend on oxygen need water to live.

Water is the essential thing, since we are talking about ALL living organisms. The most basic and important necessity they all share is the need to hydrate.

elements can be broken down through ______ processes.

Answers

nuclear processes only - not chemical
Chemical and Nuclear processes i'm pretty sure 

Sodium tends lose a single electron in natural settings. Based on what you know, what are two other elements that tend to do the same thing?

Question 4 options:

sodium and magnesium

hydrogen and helium

beryllium and boron

potassium and rubidium
**I said D**,

Answers

Pottasium and rubidium are quite similar and lose an electron in a natural setting. Both elements are known to ignite spontaneously in air. Rubidium forms amalgams with mercury and alloys with gold, iron, caesium, sodium, and potassium. It does not do so with lithium.

Answer:

D. potassium and rubdium

Which are isotopes? an atom that has an atomic number of 20 and a mass number of 42 is an isotope of an atom that has which are isotopes? an atom that has an atomic number of 20 and a mass number of 42 is an isotope of an atom that has an atomic number of 20 and a mass number of 40. an atomic number of 21 and a mass number of 42. 22 protons and 20 neutrons. 22 neutrons and 20 protons?

Answers

Isotopes have the same atomic number or same number Protons, but different mass number or neutrons.

You can say atomic number or protons.

22 neutrons 20 protons
atomic number 20 and a mass number 40
Atomic number 20 and mass # 42

Explanation:

Isotopes are defined as the species which contain same number of protons but different number of neutrons.

As the sum of all the protons present in an atom is known as atomic number. Whereas the sum of total number of protons and neutrons is known as atomic mass.

Hence, isotopes are also defined as atoms with same atomic number but different atomic mass.

For example, an atom that has an atomic number of 20 and a mass number of 42 will contain the following number of neutrons.

                 Mass number = no. of protons + no. of neutrons

                            42 = 20 + no. of neutrons

                 no. of neutrons = 42 - 20

                                            = 22

So, isotope of this atom could be [tex]^{40}_{20}A[/tex]. This means that an element with atomic number of 20 and a mass number of 40.

Thus, we can conclude that an atom that has an atomic number of 20 and a mass number of 42 is an isotope of an atom that has an atomic number of 20 and a mass number of 40.

Since, both of them contains same number of protons but different number of neutrons.

Is hot coffee an element a compound a heterogeneous mixture or a homogeneous mixture?

Answers

Final answer:

Hot coffee is a homogeneous mixture, consisting of substances that are uniformly distributed and cannot be easily separated.

Explanation:

Hot coffee is neither an element nor a compound, but rather a type of mixture. Specifically, hot coffee is a homogeneous mixture. A mixture is a material composed of two or more substances that are combined without a chemical reaction occurring, and in a homogeneous mixture, these substances are uniformly distributed. Therefore, in the case of hot coffee, the coffee solids, water, and any added sugar or cream are thoroughly mixed and cannot be easily separated, which is typical of homogeneous mixtures.

Learn more about Homogeneous Mixture here:

https://brainly.com/question/32534073

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Final answer:

Hot coffee is a homogeneous mixture, characterized by a uniform composition throughout. It is not a heterogeneous mixture or a compound.

Explanation:

Hot coffee is an example of a homogeneous mixture. This classification is due to the uniform composition throughout the coffee, which is a combination of several substances including water, coffee solids, and possibly sugar or milk. It remains homogeneous due to the heat which keeps the solids dissolved. It differs from a heterogeneous mixture, where the composition varies from point to point, and also from a compound, which is a substance formed by chemical union of two or more elements. In contrast, the constituents of a mixture like coffee can be separated by physical changes, such as evaporation.

Learn more about Homogeneous Mixture here:

https://brainly.com/question/30587533

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If exactly 50 ml of a 0.050m solution of hydrochloric acid is added to exactly 50 ml of 0.050m ammonia, what is the ph of the resulting solution?

Answers

NH3(aq) + HCl(aq) ⇒ NH4Cl(aq) >>> (1)
∵ C = n/V; C= concentration, n= No. of moles, and V= volume (L)
∴ n = C*V, n(HCl) = 0.050*(50/1000) = 0.0025 moles
n(NH3) = 0.050*(50/1000) = 0.0025 moles
So, the limiting no. of moles is 0.0025 moles >>> (2)
∵ NH3 is weak base, and HCl is strong Acid (and have the same number of moles) >>> So, without any calculation we can notice that the formed salt (NH4Cl) is acidic salt and the pH is less than 7.
From (1) and (2), The no. of moles of NH4Cl is 0.0025 moles >>> (3)
∴ the concentration of [NH4Cl] = 0.0025 / (total volume per L) 
                                                    = 0.0025 / ((50 + 50) / 1000) = 0.025 M
NH4+(aq) ⇔ NH3(aq) + H+(aq)   >>> (4)
(0.025 - x)          (x)              (x)       >>> (5)
∵ Ka = [NH3] [H+] / [NH4+]    >>>> (6)
Ka = Kw / Kb,    Kb = 1.8 * 10^-5 >>> (7)
∴ Ka = 10^-14 / 1.8*10^-5 = 5.56*10^-10  >>> (8)
From (4), (5), (7) and (8) 
 Ka = 5.56*10^-10 = (x * x) / (0.025-x) , we will assume that (0.025 - x) = 0.025
∴ x^2 = (5.56*10^-10)(0.025) = 139*10^-13 
∴ x = 3.73*10^-6 = [H+]
∵ pH = - log [H+]
∴ pH = - log 3.73*10^-6 = 5.43 

How is most carbon dioxide transported from tissues to the lungs? view available hint(s) how is most carbon dioxide transported from tissues to the lungs? as carbonic acid. as carbon dioxide gas. as bicarbonate ions (hco3−). as protons (h+)?

Answers

Most carbon dioxide is transported from tissues to the lungs  as a bicarbonate ions(HCO3-) in the plasma. Carbon dioxide is transported in the blood from the tissues to the lungs in three different ways. some of it is transported dissolved in the plasma, some is transported as carbaminohemoglobin and other as bound to proteins. However most carbon dioxide is transported as bicarbonate; as blood flows through the tissues, carbon dioxide diffuses into red blood cells, where it is converted into bicarbonate.

Severe shock occurs when blood loss of
30,20,50,10,5%

Answers

The answer to your question is over 30%

Which one has more mass a bag of cotton balls or a bag of nails and explain

Answers

You would think that the bag of nails would have more mass but their masses are identical. If you were to put them both in a vacuum chamber and let them fall from a great height, they would fall the same speed. The vacuum chamber would suck all of the air out of the cotton balls, thus making it heavier and weigh the same as the bag of nails.

Hopefully this is helpful and makes sense.
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