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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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A container is at a pressure of 3 atm and a temperature of 280K. What is the new temperature when the pressure is reduced to 1.5
GenaCL600 [577]

Answer:

140 K

Explanation:

Step 1: Given data

  • Initial pressure of the gas (P₁): 3 atm
  • Initial temperature of the gas (T₁): 280 K
  • Final pressure of the gas (P₂): 1.5 atm
  • Final temperature of the gas (T₂): ?

Step 2: Calculate the final temperature of the gas

We have a gas whose pressure is reduced. If we assume an ideal behavior, we can calculate the final temperature of the gas using Gay-Lussac's law.

T₁/P₁ = T₂/P₂

T₂ = T₁ × P₂/P₁

T₂ = 280 K × 1.5 atm/3 atm = 140 K

6 0
3 years ago
A chemical reaction produces 3.81g potassium chloride (KCl). How many formula units of potassium chloride are there? *Find Molar
Aleks04 [339]

Answer:

The number of formula units in 3.81 g of potassium chloride (KCl) is approximately 3.08 × 10²²

Explanation:

The given parameters is as follows;

The mass of potassium chloride produced in the chemical reaction (KCl) = 3.81 g

The required information = The number of formula units of potassium chloride (KCl)

The Molar Mass of KCl = 74.5513 g/mol

The \ number \ of \ moles \ of \ a \ substance, n = \dfrac{The  \  mass  \  of  \  the substance}{The   \  Molar  \   Mass   \  of  \   the   \  substance}

Therefore, we have;

The \ number \ of \ moles \ of \ KCl= \dfrac{3.81 \ g}{74.5513 \ g/mol} \approx 0.051106 \ moles

1 mole of a substance, contains Avogadro's number (6.022 × 10²³) of  formula units

Therefore;

0.051106 moles of KCl contains 0.051106 × 6.022 × 10²³  ≈ 3.077588 × 10²² formula units

From which we have, the number of formula units in 3.81 g of potassium chloride (KCl) ≈ 3.08 × 10²² formula units.

8 0
2 years ago
Magnesium has three naturally occurring isotopes with masses of 23.99 amuamu, 24.99 amuamu, and 25.98 amuamu and natural abundan
bonufazy [111]

Answer:

24.309 g/mol

Explanation:

To get the atomic mass, all we have to do is calculate with the masses of the three isotope, the real quantity present, taking account of the percent and then, do a sum of these three values. Like a pondered media.

For the first isotope:

23.99 * (78.99/100) = 18.95 g/mol

For the second isotope:

24.99 * (10/100) = 2.499 g/mol

For the last isotope:

25.98 * (11.01/100) = 2.86 g/mol

Now, let's sum all three together

AW = 18.95 + 2.499 + 2.86

AW = 24.309 g/mol

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3 years ago
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3 years ago
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What volume would 3.00 moles of neon gas have at 295 K and 645 mmHg?
LUCKY_DIMON [66]

Answer:

V = 85.619 L

Explanation:

To solve, we can use the ideal gas law equation, PV = nRT.

P = pressure (645 mmHg)

V = volume (?)

n = amount of substance (3.00 mol)

R = ideal gas constant (62.4 L mmHg/mole K)

T = temperature (295K)

Now we would plug in the appropriate numbers into the equation using the information given and solve for V.

(645)(V) = (3.00)(62.4)(295)

(V) = (3.00)(62.4)(295)/645

V = 85.619 L

6 0
3 years ago
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