Calculate Delta H in KJ for the following reactions using heats of formation:
a) 2C2H6 (g) + 7O2 (g) ---> 4CO2 (g) +6H2O (g)

b) 2PbO (s) + PbO2 (s) ---> Pb3O4 (s)

I strongly would choose D

Answer:

2.067 L ≅ 2.07 L.

Explanation:

CS₂(g) + 3O₂(g) → CO₂(g) + 2SO₂(g),

It is clear that 1.0 mole of CS₂ react with 3.0 mole of O₂ to produce 1.0 mole of CO₂ and 2.0 moles of SO₂.

It is known that at STP: every 1.0 mol of any gas occupies 22.4 L.

using cross multiplication:

1.0 mol of O₂ represents → 22.4 L.

??? mol of O₂ represents → 3.1 L.

∴ 3.1 L of O₂ represents = (1.0 mol)(3.1 L)/(22.4 L) = 0.1384 mol.

Using cross multiplication:

3.0 mol of O₂ produce → 2.0 mol of SO₂, from stichiometry.

0.1384 mol of O₂ produce → ??? mol of SO₂.

∴ The no. of moles of SO₂ = (2.0 mol)(0.1384 mol)/(3.0 mol) = 0.09227 mol.

1.0 mol of SO₂ represents → 22.4 L, at STP.

0.09227 mol of SO₂ represents → ??? L.

∴ The no. of liters of SO₂ will be produced = (0.09227 mol)(22.4 L)/(1.0 mol) = 2.067 L ≅ 2.07 L.

Answer:

26

Explanation:

THIS IS FOR AP EX I SWEAR TO GOD, IT IS NOT 56.

Atoms with an atomic number greater than 92, like U-235 or U-238 and 239Pu, are usually the ones to undergo nuclear fission. Fission involves a large nucleus splitting into smaller parts and often releasing neutrons that can continue the reaction. However, the outcome of the process varies.

Atoms with an atomic number greater than 92, such as Uranium-235 or 238 and Plutonium-239, are typically the ones that undergo nuclear fission. Nuclear fission refers to the process of a large nucleus splitting into smaller nuclei, often induced by bombardment with neutrons. When a nucleus such as Uranium-235 (235U) undergoes fission, as in the example of 235U + n, the large U-235 nucleus produces two or three neutrons in the process, each capable of causing fission in another nucleus, which can potentially lead to a nuclear chain reaction.

However, it's important to note that not all atoms with an atomic number greater than 92 will necessarily go through fission. Fission is a statistical process and various products are produced with different probabilities. Therefore, though certain isotopes like 235U and 239Pu are easier to instigate fission in, the outcome can vary.

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Answer: 8.2689J/gC

H=mc(change in temp)

H(water)=50*4.184*3.32=694.5J

H(zinc)=694.5J

c(zinc)=694.5/(25.3*3.32)=8.2689J/gC

Taking into account the expressions and the principle of calorimetry that ensures that the body with a higher temperature will give up thermal energy to the one with a lower temperature until both are in an identical energy state, the specific heat of the zinc is 0.383 [tex]\frac{J}{gC}[/tex].

In first place, you need to know that the Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

The equation for calculating heat exchanges results from the product of the specific heat times the mass of the body and the temperature difference. That is, the amount of heat that a body receives or transmits is determined by:

Q = c×m×ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation (being ΔT= Tfinal - Tinitial)

On the other hand, a calorimeter is a device used to measure the heat of flow of a chemical reaction or physical change. It consists of a container built with insulating walls that limit heat exchanges with the environment in which the substances that give and receive heat are found. Being in a container with insulating walls that do not allow the exchange of energy with the outside, a principle ensures that the body with a higher temperature will give up thermal energy to the one with a lower temperature until both are in an identical energy state. That is, the heat change in the system must be 0. This is:

Qsystem= Qabsorbed  + Qyielded

0= Qabsorbed  + Qyielded

In this case, the water, when going from a higher temperature to a lower one, delivers a quantity of heat. Then

Qyielded= Qwater= cwater×mwater ×ΔT= 4.184[tex]\frac{J}{gC}[/tex] × 50 g× (96.68 C - 100 C)

On the other hand, the heat given off by the water will be absorbed by the zinc. Then:

Qabsorbed= Qzinc= czinc×mzinc×ΔT= czinc× 25.3 g× (96.68 C - 25 C)

Taking into account the principle mentioned above, it is possible to express:

0= czinc× 25.3 g× (96.68 C - 25 C) + 4.184[tex]\frac{J}{gC}[/tex] × 50 g× (96.68 C - 100 C)

Solving:

0= czinc× 25.3 g× (96.68 C - 25 C) + 4.184[tex]\frac{J}{gC}[/tex] × 50 g× (96.68 C - 100 C)

0= czinc× 25.3 g× 71.68 C + 4.184[tex]\frac{J}{gC}[/tex] × 50 g× (-3.32 C)

0= czinc× 1813.504 g×C - 694.544 J

694.544 J=  czinc× 1813.504 g×C

[tex]\frac{694.544 J}{1813.504 gC} =czinc[/tex]

0.383 [tex]\frac{J}{gC}[/tex] =czinc

In summary, the specific heat of the zinc is 0.383 [tex]\frac{J}{gC}[/tex]

Learn more about calorimeter:

Fossils found on both landmasses can indicate whether they were connected in the past.

Hello!

I know I am super late to this but this answer is so the other person can have brainliest :)

Have a great day!

~Grace~

Answer:

0.643 mol.

Explanation:

where, P is the pressure of the gas in atm (P = 4.0 atm).  

V is the volume of the gas in L (V = 4000 mL = 4.0 L).  

n is the no. of moles of the gas in mol (n = ??? mol).

R is the general gas constant (R = 0.0821 L.atm/mol.K),  

T is the temperature of the gas in K (T = 30ºC + 273 = 303 K).

∴ n = PV/RT = (4.0 atm)(4.0 L)/(0.0821 L.atm/mol.K)(303 K) = 0.643 mol.

D. All Of These Would Help An Individual

Answer:

1.17 M

Explanation:

molarity of a solution is defined as the number of moles dissolved in 1 L of solution

molarity = number of moles / volume of solution

volume of solution is 0.075 L

number of moles of CuSO₄ - 0.0877 mol

substituting these values in the equation

molarity = 0.0877 mol / 0.075 L

molarity = 1.17 mol/L

molarity of CuSO₄ is 1.17 M

Answer:

Hydrofluorocarbons

Explanation:

Answer:

Hydrofluorocarbons

Explanation:

Earlier chlorofluorocarbons were used for refrigeration purpose. But they were banned as they were primary cause of ozone depletion.

In order to replace  chlorofluorocarbons, now hydrofluorocarbons are used which helps to protect earth from stratospheric ozone-depleting substances.

The difference between chlorofluorocarbons and hydrofluorocarbons is of hydrogen. In hydrofluorocarbons one of the halogen is being replaced by hydrogen.

Answer:

[tex]\boxed{\text{12 p, 12 n, and 12 e}}[/tex]

Explanation:

No atoms of Mg have a mass of 24.3050 u. That is the average mass of all the isotopes of Mg.

However, the most common isotope of Mg is ₁₂²⁴Mg (mass = 23.99 u)

The atomic number of Mg is 12. It has 12 protons.

The atomic mass of ²⁴Mg is 24. That's the total number of protons and neutrons.

 p + n = 24

12 + n = 24

       n = 12

An atom of ²⁴Mg has 12 neutrons.

If the atom is neutral, the number of electrons equals the number of protons.

e = p = 12

[tex]\text{An atom of }$^{24}$\text{Mg contains }\boxed{\textbf{12 p, 12 n, and 12 e}}[/tex]

Top answer

it seems most correct

Answer:

northern winds

Explanation:

The answer is SW to NW

Answer:

The conditions for hurricanes differ from the conditions of tornadoes because of D, Tornadoes form over land, while hurricanes form over bodies of water.

Explanation:

Hurricanes form over warm water in tropical ocean settings and tornadoes form over land within storms.

Answer:

70.61°c=T₂

Explanation:

This question is on Combined Gas Laws

The volume of a gas is directly proportional to the absolute temperature and inversely proportional to the pressure.

P₁V₁T₁=P₂V₂T₂

where

P₁=Initial pressure, P₂=final pressure

V₁=Initial volume,V₂=final volume

T₁=Initial temperature in Kevin, T₂=final temperature in Kelvin

Given

P₁=398mm Hg,  V₁=29 L  and T₁=293 K

P₂=307 mm Hg, V₂=156 L  and T₂=?

Solution

P₁V₁T₁=P₂V₂T₂

Substitute values

398×29×293=307×156×T₂

3381806=47892T₂

3381806/47892=T₂

70.61°c=T₂

70.61+273=343.61 K

Answer:

[tex]\boxed{\text{-8.5 mV}}[/tex]

Explanation:

The SHE is not under standard conditions, so we must use the Nernst Equation, which relates the cell potential to the standard potential and to the activities of the electroactive species.  

[tex]E = E^{\circ} - \frac{RT}{zF}lnQ[/tex]

Step 1. Write the equation for the cell reaction

Anode:    H₂(1 atm) ⇌ 2H⁺(1 mol·L⁻¹) + 2e⁻

Cathode: 2H⁺(0.88 mol·L⁻¹) + 2e⁻ ⇌ H₂(1.7 atm)                                  

Overall:   H₂(1 atm) + 2H⁺(0.88 mol·L⁻¹) ⇌ 2H⁺(1 mol·L⁻¹) + H₂(1.7 atm)

Step 2. Calculate Q

[tex]Q = \frac{1 \times 1.7 }{ 1 \times 0.88} = 1.93[/tex]

Step 3. Apply the Nernst equation

Data:

E° = 0 V

R = 8.314 J·K⁻¹mol⁻¹

T = 298 K

n = 2

F = 96 485 C/mol

Calculation:

[tex]E = 0 - \frac{8.314 \times 298}{2 \times 96 485}\ln1.93[/tex]

= -0.0128 × 0.658

= -0.0085 V

= [tex]\boxed{\text{-8.5 mV}}[/tex]

Answer:

(β⁺), and another one is 01e

It's C that's correct because it's very true...

Answer:

the answer is B

Explanation:

Answer:

M of HI = 5.4 M.

Explanation:

(XMV) acid = (XMV) base.

where, X is the no. of (H) or (OH) reproducible in acid or base, respectively.

M is the molarity of the acid or base.

V is the volume of the acid or base.

(XMV) HI = (XMV) Ca(OH)₂.

For HI; X = 1, M = ??? M, V = 25.0 mL.

For Ca(OH)₂, X = 2, M = 1.5 M, V = 45.0 mL.

∴ M of HI = (XMV) Ca(OH)₂ / (XV) HI = (2)(1.5 M)(45.0 mL) / (1)(25.0 mL) = 5.4 M.

Answer:

pseudopodia

Explanation:

Giant amoebae engulf their prey by gathering of pseudopods around the bacteria, as the bacteria is drawn in, the cell membrane that surrounds it, pinches off to form an inter-cellular compartment called the vacuole.

pops because of increasing the atmospheric pressure

Answer : The temperature of balloon increases to 10 times of original temperature.

Explanation :

In this problem, volume remain constant. The temperature and pressure will vary.

Gay-Lussac's Law : It is defined as the pressure of the gas is directly proportional to the temperature of the gas at constant volume and number of moles.

[tex]P\propto T[/tex]

or,

[tex]\frac{P_1}{P_2}=\frac{T_1}{T_2}[/tex]

where,

[tex]P_1[/tex] = let initial pressure = x

[tex]P_2[/tex] = final pressure = 10x

[tex]T_1[/tex] = initial temperature

[tex]T_2[/tex] = final temperature

Now put all the given values in the above equation, we get:

[tex]\frac{x}{10x}=\frac{T_1}{T_2}[/tex]

[tex]\frac{T_1}{T_2}=\frac{1}{10}[/tex]

[tex]T_2=10T_1[/tex]

From this we conclude that, the temperature increases to 10 times of original temperature.

Hence, the temperature of balloon increases to 10 times of original temperature.

Answer:

D. insufficient supply of oxygen

Explanation:

Combustion is an exothermic reaction which involves the burning of a compound in the presence of oxygen. Combustion is a very useful life process as it produces heat and light.

For a complete combustion reaction to occur, the compound must be burnt over excess oxygen. The product is usually carbondioxide and water with release of some particulate matter.

In incomplete combustion, there is deficiency of oxygen. Here, oxygen becomes the limiting agent and it drives the reaction to an end. Incomplete combustion is always accompanied with the production of poisonous carbon monoxide and Carbon. We see incomplete combustion when smoke forms or when burning is accompanied by production of soot.

What makes a combustive process complete or not is the availability of oxygen gas for the reaction.

An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be represented as Na+(aq) + Cl−(aq).

Sugar is the solute and water is the solvent.

A solution is a homogeneous mixture of one or more solutes dissolved in a solvent.

Solvent: the substance in which a solute dissolves to produce a homogeneous mixture.

Solute: the substance that dissolves in a solvent to produce a homogeneous mixture.

Hence, sugar is the solute and water is the solvent.

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Answer:

Explanation:

One: You could mix a small sample of it with a reactive metal. Underline small. You should see gas bubbles being given up. Usually the bubbles are hydrogen.

Example : K + HCl ===> KCl + H2

Two: You could use an indicator to watch it turn color as it goes from acidic to neutral. Litmus will go from red to blue under these conditions.

Three: Those are the two safest ways. If you knew the acid was dilute, you could put a small (underline small again) amount on your tongue. If it tastes like orange juice, it is likely an acid. This is a test every textbook mentions. You should never do it under any circumstances.

Answer:

1. Using Litmus papers. Litmus paper will turn blue if solution is acidic or it will turn blue if it is basic. ... If pH is below 7 or reddish then the given solution is acidic and if pH is higher than 7 or bluish then the solution is basic.

Explanation:

Answer:

1340 mg

Explanation:

concentration is the number of moles of solute in a 1000 mL of solution

the concentration of KCl solution is 1.20 M

There are 1.20 mol in 1000 mL of solution

a volume of 1000 mL contains - 1.20 mol

therefore 15 mL solution contains - 1.20 mol / 1000 mL x 15 mL = 0.018 mol

the molar mass of KCl is - 74.5 g/mol

mass of 1 mol is - 74.5 g

therefore mass of 0.018 mol is - 74.5 g/mol x 0.018 mol = 1.34 g

1000 mg - 1 g

therefore 1.34 g in milligrams is - 1.34 g x 1000 mg/g = 1340 mg

The answer is:

Hence, the new pressure will be 2.07 atm.

[tex]P_{2}=2.07atm[/tex]

Since we know that the gas is inside of a rigid container, meaning that the volume will be kept constant, we can solve the problem using the Gay-Lussac's Law.

The the Gay-Lussac's Law establishes that when an ideal gas is kept at constant volume, the pressure and the temperature will be proportional.

We need to pay special attention when we are working with the Gay-Lussac's Law since its equations with absolute temperatures (Kelvin ), so, if we are working with relative temperatures such as Celsius degrees or Fahrenheit degrees, we need to convert the temperatures to Kelvin (absolute temperature)

We can convert from Celsius degrees to Kelvin using the following formula:

[tex]Temperature(K)=Temperature(C\°)+273[/tex]

Then we have the Gay-Lussac's equation:

[tex]\frac{P_{1}}{T_{1}}=\frac{P_{2}}{T_{2}}[/tex]

Therefore, we are given the following information:

[tex]T_{1}=30\° \\P_{1}=2atm\\T_{2}=40\°[/tex]

Therefore, converting the given temperatures from Celsius degrees to Kelvin, we have:

[tex]T_{1}=30C\°=30+273K=303K\\\\T_{1}=40C\°=40+273K=313K\\[/tex]

Now, calculating we have:

[tex]\frac{P_{1}}{T_{1}}=\frac{P_{2}}{T_{2}}[/tex]

[tex]P_{2}=\frac{P_{1}}{T_{1}}*T_{2}\\\\P_{2}=\frac{2atm}{303K}*313K=2.07atm[/tex]

Hence, the new pressure will be 2.07 atm.

[tex]P_{2}=2.07atm[/tex]

Have a nice day!

Answer: the ground state

Explanation: when electron's are attracted to something, they typically rotate counter clockwise, in theory we can apply this to darwin, i recomend that book btw but counter clockwise goes to ground

Answer:

Ground state is correct

Answer:

1.143 M.

Explanation:

Molarity is defined as the no. of moles of a solute per 1.0 L of the solution.

M = (no. of moles of solute)/(V of the solution (L)).

∴ M = (mass/molar mass)of KNO₃/(V of the solution (L)).

∴ M = (mass/molar mass)of KNO₃/(V of the solution (L)) = (53.27 g / 101.1 g/mol)/(0.461 L) = 1.143 M.

Answer:

Explanation:

Uniformitarianism - "The Present is the Key to the Past"

Uniformitarianism is a geological doctrine. It states that current geologic processes, occurring at the same rates observed today, in the same manner, account for all of Earth's geological features. Thus, it assumes that geological processes are essentially unchanged today from those of the unobservable past, and that there have been no cataclysmic events in earth's history. As present processes are thought to explain all past events, the Uniformitarian slogan is, "the present is the key to the past.

Answer:

I hope this helps! <3

Explanation:

Answer:

pH Scale:

The pH scale refers to the negative logarithm of molar concentration of hydrogen ions: pH = -log [H+].

Characteristics:

The pH scale ranges from 0 to 14. A solution of a compound of pH 7 or pOH 7 is a neutral solution. Solutions of pH less than 7  are acidic and more than 7 are basic.

Low pH of water is acidic in nature as it enters into the ground and collects in streams, it can have bad impacts on the ecosystem.  

Answer:

[tex]\boxed{\text{two}}[/tex]

Explanation:

In multiplication  and division problems, your answer can have no more significant figures than the number with the fewest significant figures.

[tex]\dfrac{7.06 \times 10^{5}}{5.3 \times 10^{-2}}= 1.332 075 472 \times 10^{7}[/tex] (by my calculator)  

There are three significant figures in 7.06 and two in 2.3.

You must round to [tex]\boxed{\textbf{two}}[/tex] significant figures and report the answer as 1.3 × 1.0⁷.

On dividing the exponents, [tex]\frac{7.06* 10^{5} }{5.3*10^{-2}} = 1.33 * 10^{7}[/tex].

To divide them, you take the exponent value in the numerator (the top exponent) and subtract the exponent value of the denominator (the bottom exponent).

[tex]= \frac{7.06* 10^{5} }{5.3*10^{-2}} \\\\= \frac{7.06}{5.3}* 10^{5+2}\\ \\= 1.33 * 10^{7}[/tex]

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An empirical formula is the chemical formula showing the simplest ratio of elements in a compound rather than the total number of atoms.

For example the molecule 'CH2O' is the empirical formula for glucose.