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3 years ago

If 3 moles of a compound use 12 J of energy in a reaction, what is the Hreaction in kJ/mol

Chemistry

1 answer:

igomit [66]3 years ago

5 0

Answer:

$\Delta _RH=4x10^{-3}\frac{kJ}{mol}$

Explanation:

Hello,

In this case, the molar enthalpy of reaction is obtained by dividing the involved energy by the reacting moles:

$\Delta _RH=\frac{12J}{3mol} =4\frac{J}{mol}$

Thus, it is important to notice that the compound "uses" the energy, it means that it absorbs the energy, for that reason the sign is positive. Moreover, computing the result in kJ/mol we finally obtain:

$\Delta _RH=4\frac{J}{mol}*\frac{1kJ}{1000J} =4x10^{-3}\frac{kJ}{mol}$

Best regards.

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A monoprotic weak acid when dissolved in water is 0.66% dissociated and produces a solution with a pH of 3.04. Calculate the Ka

raketka [301]

Answer:

Ka = 6.02x10⁻⁶

Explanation:

The equilibrium that takes place is:

HA ⇄ H⁺ + A⁻

Ka = [H⁺][A⁻]/[HA]

We calculate [H⁺] from the pH:

pH = -log[H⁺]

[H⁺] = $10^{-pH}$

[H⁺] = 9.12x10⁻⁴ M

Keep in mind that [H⁺]=[A⁻].

As for [HA], we know the acid is 0.66% dissociated, in other words:

[HA] * 0.66/100 = [H⁺]

We calculate [HA]:

[HA] = 0.138 M

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3 years ago

Does salt affect how long an ice cube melts?

Mashutka [201]

Answer:

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3 years ago

Pentane is a small liquid hydrocarbon, between propane and gasoline in size at C5H12. The density of pentane is 0.626 g/mL and i

Goshia [24]

Answer : The fuel value and the fuel density of pentane is, 49.09 kJ/g and $3.073\times 10^4kJ/L$ respectively.

Explanation :

Fuel value : It is defined as the amount of energy released from the combustion of hydrocarbon fuels. The fuel value always in positive and in kilojoule per gram (kJ/g).

As we are given that:

$\Delta H^o_{comb}=-3535kJ/mol$

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Fuel value = 49.09 kJ/g

Now we have to calculate the fuel density of pentane.

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Fuel density = 30.73 kJ/mL = $3.073\times 10^4kJ/L$

Thus, the fuel density of pentane is $3.073\times 10^4kJ/L$

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4 years ago

Carbonyl fluoride, COF2, is an important intermediate used in the production of fluorine-containing compounds. For instance, it

lions [1.4K]

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Explanation:

We are given:

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At eqllm: 2.00-2x x x

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gogolik [260]

Answer:

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