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3 years ago

A compound contains 75% carbon and 25%

Chemistry

1 answer:

masha68 [24]3 years ago

5 0

Answer:

CH4

Explanation:

Carbon: 75%/12grams = 6.25

6.25/6.25 = 1

Hyrdrogen: 25/1gram = 25

25/6.25 = 4

C1H4 = CH4

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The complete combustion of propane (C3H8) in the presence of oxygen yields CO2 and H2O: C3H8 (g) + 5O2 (g) 3CO2 (g) + 4H2O (g) a

mixas84 [53]

Answer:

26.9 L is the volume of CO₂, we obtained

Explanation:

The reaction is: C₃H₈(g) + 5O₂(g) → 3CO₂ (g) + 4H₂O (g)

Let's determine the reactants moles:

27.5 g . 1mol / 44 g = 0.625 moles

We need density of O₂ to determine mass and then, the moles.

O₂ density = O₂ mass / O₂ volume

O₂ density . O₂ volume = O₂ mass

1.429 g/L . 45L = O₂ mass → 64.3 g

Moles of O₂ → 64.3 g . 1mol/32g = 2.009 moles

Let's find out the limiting reactant:

1 mol of propane needs 5 moles of oxygen to react

Then, 0.625 moles will react with (0.625 . 5)/1 = 3.125 moles of O₂

Oxygen is the limiting reactant, we need 3.125 moles but we only have 2.009 moles

Ratio is 5:3. 5 moles of O₂ produce 3 moles of CO₂

Therefore, 2.009 moles of O₂ must produce (2.009 .3) /5 = 1.21 moles of CO₂. Let's find out the volume, by Ideal Gases Law (STP are 1 atm and 273K, the standard conditions)

1 atm . V = 1.21 moles . 0.082 . 273K

V = (1.21 moles . 0.082 . 273K) / 1atm = 26.9 L

3 0

3 years ago

How much heat is released when 75 g of octane is burned completely if the enthalpy of combustion is -5,500 kJ/mol CsH18? C8H18 +

aalyn [17]

Answer : The correct option is, (D) 3600 kJ

Explanation :

Mass of octane = 75 g

Molar mass of octane = 114.23 g/mole

Enthalpy of combustion = -5500 kJ/mol

First we have to calculate the moles of octane.

$\text{ Moles of octane}=\frac{\text{ Mass of octane}}{\text{ Molar mass of octane}}=\frac{75g}{114.23g/mole}=0.656moles$

Now we have to calculate the heat released in the reaction.

As, 1 mole of octane released heat = -5500 kJ

So, 0.656 mole of octane released heat = 0.656 × (-5500 kJ)

= -3608 kJ

≈ -3600 kJ

Therefore, the heat released in the reaction is 3600 kJ

5 0

3 years ago

Direct electron transfer from a singlet reduced species to a triplet oxidizing species is quantum-mechanically forbidden

posledela

Direct electron transfer from a a singlet reduced species to a triplet oxidizing species is quantum-mechanically forbidden.

<h3><u>Transfer from singlet to triplet:</u></h3>

Either an excited singlet state or an excited triplet state will occur when an electron in a molecule with a singlet ground state is stimulated (through radiation absorption) to a higher energy level.
All electron spins in a molecule electronic state known as a singlet are coupled.
In other words, the ground state electron and the stimulated electron's spin are still coupled (a pair of electrons in the same energy level must have opposite spins, per the Pauli exclusion principle).
The excited electron and ground state electron are parallel in a triplet state because they are no longer coupled (same spin).
It is less likely that a triplet state would arise when the molecule absorbs radiation since excitation to a triplet state necessitates an additional "forbidden" spin transfer.

To view more questions on quantum mechanism, refer to:

brainly.com/question/13639384

#SPJ4

8 0

2 years ago

What is true at stp? A)the temperature is 273.15 kelvin, B)one mole of gas occupies one liter of volume. C)pressure is at 101 vo

fgiga [73]

STP stands for standard temperature and pressure. Standard pressure is equivalent to 1 atm, and standard temperature is equivalent to 273.15 K. Therefore, your answer is A. the temperature is 273.15 kelvin.

Hope this helps!

3 0

3 years ago

Ava’s best friend has an indoor cat. Ava notices that she sneezes every time that she visits her friend. Ava suspects that she i

zlopas [31]

Answer:

I say for her to test her suspicion by going to see an allergist to diagnose the allergy.

7 0

3 years ago