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olga_2 [115]
3 years ago
11

Based on the following reaction, determine how much heat is released if 500. grams of methane is combusted in excess oxygen: CH4

+ 2 O2  CO2 + 2 H2O H= – 890 kJ
Chemistry
1 answer:
EastWind [94]3 years ago
3 0

Answer:

- 13,150.6kJ

Explanation:

CH4 + 2 O2 ------> CO2 + 2 H2O ΔH= – 890 kJ

The ΔH is enthalpy change of combustion , which is the heat is either absorbed or released by the combustion of one mole of a substance.

ΔH=−890 kJ/mol (released in the combustion of one mole of methane)

using the molar mass  (in grams )of methane to get moles of sample

(237g × 1 mole of CH4)/16.04g=14.776 moles  of CH4

Since 1 mole produces 890 kJ of heat upon combustion, then 14.776 moles will produce

ΔH = 14.776moles of CH4 × 890kJ/1mole of CH4

=13,150.6kJ

Therefore ΔH = - 13,150.6kJ

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When cyclohexene is treated with KMnO4, H2O, the syn-1,2-diol is produced. What reaction occurs when benzene is similarly treate
Ulleksa [173]

Answer:

No reaction is observed

Explanation:

The benzene ring is aromatic. Being an aromatic ring, the benzene ring is remarkably stable to all reactions that destroy the aromatic ring.

Alkenes are oxidized to alkanols in the presence of KMnO4 but this reaction does not occur with benzene. However, substituted benzenes having hydrogen atoms attached to the substituent carbon atom can be oxidized to the corresponding carboxylic acid.

7 0
3 years ago
Calculate the standard reaction enthalpy for the reaction NO2(g) → NO(g) + O(g) given +142.7 kJ/mol for the standard enthalpy of
bulgar [2K]

Answer:

The standard reaction enthalpy for the given reaction is 235.15 kJ/mol.

Explanation:

O_2(g) \rightarrow \frac{2}{3}O_3(g),\Delta H^o_{1}=142.7 kJ/mol..[1]

O_2(g) \rightarrow 2 O(g),\Delta H^o_{2}=498.4 kJ/mol..[2]

NO(g) + O_3(g)\rightarrow NO_2(g) + O_2(g) ,\Delta H^o_{3} = -200 kJ/mol..[3]

NO_2(g)\rightarrow NO(g) + O(g),\Delta H^o_{4}=?..[4]

Using Hess's law:

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

2 × [4] = [2]- (3 ) × [1] - (2) × [3]

2\times \Delta H^o_{4}=\Delta H^o_{2} -3\times \Delta H^o_{1}-2\times \Delta H^o_{3}

2\times \Delta H^o_{4}=498.4 kJ/mol-3\times 142.7 kJ/mol-2\times -200 kJ/mol

2\times \Delta H^o_{4}=470.3 kJ/mol

\Delta H^o_{4}=\frac{470.3 kJ/mol}{2}=235.15 kJ/mol

The standard reaction enthalpy for the given reaction is 235.15 kJ/mol.

7 0
3 years ago
Styrofoam has a density of 0.075 g/mL. What is the volume of 21.80 g of Styrofoam?
LekaFEV [45]

The answer is 290.66 mL

Explanation:

The density of any substance including styrofoam is determined by two main factors: mass (atoms in the substance) and volume (space occupied). Moreover, the volume or mass of the substance can be calculated by using the density as these variables are related. Below I show the process:

density = mass / volume

mass = density x volume

volume = mass / density

volume = 21.80 g / 0.075 g/mL

volume = 290.66 mL

4 0
3 years ago
At what temperature, in Kelvin, will a 250 milliliter cylinder containing 0.100 moles of helium gas have a pressure of 2.50 atmo
lozanna [386]
Use the ideal gas formula-----> PV= nRT

P= 2.50 atm
V= 250 mL= 0.250 L
n= 0.100 moles
R= 0.0821 atmxL/molesxK
T= ?

T= PV/nR

T= (2.50 atm x 0.250 L) / (0.100 moles x 0.0821)= 76.1 K
7 0
3 years ago
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castortr0y [4]
It's asking about air currents and temperature and how they affect each other. Since the land is hotter than the water during the day, it will create different pressures that force air to move. <span>The wind will blow from the higher pressure over the water to lower pressure over the land </span>causing<span> the </span><span>sea breeze. The opposite happens at night, and that causes a land breeze.
</span>
4 0
3 years ago
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