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ohaa [14]
2 years ago
9

The mole fraction of oxygen molecules in dry air is 0.2095. What volume of dry air at 1.00 atm and 25°C is required for burning

completely 1.00 L of octane (C8H18, density = 0.7025 g/mL), yielding carbon dioxide and water?
Chemistry
1 answer:
Temka [501]2 years ago
0 0

Answer:

V = 8963 L

Explanation:

Our strategy here is to realize this problem involves stoichiometric calculation based on the balanced chemical equation for the combustion of octane:

C₈H₁₈ + 25/2 O₂ ⇒ 8 CO₂ + 9 H₂O

From the density of octane we can obtain the number of moles:

D = m/V ⇒ m= D x V = 0.7025 g/mL x ( 1000 mL) = 702.5 g

MW octane  = 702.5 g/ 114.23 g/mol = 6.15 mol

Required  mol oxygen to react with octane:

6.15 mol octane x  25/2 mol O₂ / mol octane = 76.8 mol O₂

Now mol fraction is given by mol O₂ / total number mol air ⇒

n air = 76.8 mol O₂ / (0.2095 mol O₂ / mol air )  = 366.59 mol air

and from the ideal gas law we can compute the volume of air:

PV = nRT  ⇒ V = nRT/P

V = 366.59 mol air x 0.08205 Latm/Kmol x (25+ 273) K/ 1 atm

   = 8,963 Lts

Note we treat here  air as a compund which is allowed in combustion problems.

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A 0.100 m solution of which one of the following solutes will have the highest vapor pressure? A 0.100 m solution of which one o
Assoli18 [71]

Explanation:

Vapor pressure is defined as the pressure exerted by vapors or gas on the surface of a liquid.

Vapor pressure is inversely proportional to the number of solute particles. Hence, more will be the solute particles lower will be the vapor pressure and vice-versa.

(a)   KClO_{4} \rightarrow K^{+} + ClO^{-}_{4}

It dissociates to give two particles.

(b)  Ca(ClO_{4})_{2} \rightarrow Ca^{2+} + 2ClO^{-}_{4}

Total number of particles it give upon dissociation are 1 + 2 = 3. Hence, it gives 3 particles.

(c)   Al(ClO_{4})_{3} \rightarrow Al^{3+} + 3ClO^{-}_{4}

Total number of particles it give upon dissociation are 1 + 3 = 4. Hence, it gives 4 particles.

(d)  Surcose being a cobvalent compound doe not dissociate into ions. Therefore, there will be only 1 particle is present.

(e)   NaCl \rightarrow Na^{+} + Cl^{-}

Total number of particles it give upon dissociation are 1 + 1 = 2. Hence, it gives 2 particles.

5 0
2 years ago
The common constituent in all acid solutions is
Oksi-84 [34.3K]

Answer:

H+/H3O , H2O

Explanation:

The ability to be a proton donor is the Bronsted-Lowry definition of acids. The Lewis definition of an acid is an electron pair acceptor, which covers molecules liKE BF3

The ability to accept a pair of electrons is what is common to all acids, not the ability to be a proton donor.

All acid solutions contain hydronium ions (H3O+), hydroxide ions (OH-) and water molecules. Each different acid solution will then have an anion that is exclusive to that acid. For example, hydrochloric acid solution will contain all of the above and chloride ions (Cl-).

All acids contain the acidic substance dissolved in water. Water naturally dissociates to a small amount, creating hydronium and hydroxide ions. But most of the water remains as water molecules.

Then when we add an acid, like HCl, the oxygen on the water attracts the hydrogen from the HCl. The electrons in the covalent bond remain with the chlorine, giving it a negative charge and thus it becomes the chloride ion (Cl-). The hydrogen now has a positive charge and as said before, is attracted to the water (specifically the lone pair of electrons on the oxygen) to create hydronium ions.

This creates extra hydronium ions, making the solution acidic. But remember, there are still water molecules, hydroxide ions and the negative ion all in solution for all acids.

8 0
2 years ago
explain what you would do expect caesium astatide to look like .will it be soluble in water ?explain your reasoning​
son4ous [18]

Answer:

it will not be soluble in water Becoz it can only be

separated by passing it through silver nitrate solution

Explanation:

i hope you understand

3 0
2 years ago
A sample of hydrogen was collected by water displacement at 23.0°C and an atmospheric pressure of 735 mmHg. Its volume is 568 mL
ziro4ka [17]

Answer:

V = 552 mL or 0.552 L

Explanation:

First, we need to calculate the number of moles of H2 using the ideal gas equation which is:

PV = nRT

Solving for n:

n = PV / RT

Where:

P = Pressure

V = Volume

R = Gas constant (0.082 L atm / K mol)

T = Temperature in K

Let's convert first both pressure in atm, remember that 1 atm = 760 mmHg

P = 735 / 760 = 0.967 atm

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Finally temperature to Kelvin:

T = 23 + 273.15 = 296.15 K

Now, at first the hydrogen was collected by water displacement so pressure is:

P = 0.967 - 0.028 = 0.939 atm

Now the moles of hydrogen:

n = 0.939 * 0.568 / 0.082 * 296.15

n = 0.022 moles

Now that we have the moles, let's calculate the volume when the pressure is 735 mmHg

V = nRT/P

V = 0.022 * 0.082 * 296.15 / 0.967

V = 0.552 L or 552 mL

This is the volume that hydrogen occupies.

6 0
2 years ago
To construct the galvanic cell illustrated above, the salt bridge was prepared by soaking a piece of cotton in 5.0MNaNO3(aq) bef
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Answer:

The cell reaction reaches equilibrium quickly and the cell emf becomes zero.

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A solution of a salt that dissociates easily is normally used. Water is ineffective at functioning as a salt bridge. Hence the effect stated in the answer.

4 0
2 years ago
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