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3 years ago

Using the bond energies provided below, calculate ?H° for the reaction

Chemistry

1 answer:

shusha [124]3 years ago

8 0

Answer:

ΔHºrxn = - 440 kJ

Explanation:

What we need to remember in this question is that given the bond energies for a reaction, the enthalpy change , ΔHº , is given by the expression:

ΔHºrxn = ∑ energies of the bonds broken - ∑ energies of the bonds formed.

where s ∑ is summatory.

The reaction is CH₄(g) + 4 Cl₂(g) ⇒ CCl₄(g) + 4 HCl(g)

So lets make the inventory of the bond broken and bonds formed

Bonds Broken:

4 C-H = 4 mol (413 kJ/mol ) = 1652 kJ

4 Cl-Cl = 4 mol ( 243 kJ/mol = 972 kJ/mol

Bond Formed:

4 C-Cl = 4 mol (339 kJ/mol ) = 1356 kJ

4 H-Cl = 4 mol (427 kJ/mol ) = 1708 kJ

Now we can calculate ΔHºrxn :

ΔHºrxn = ∑ energies of the bonds broken - ∑ energies of the bonds formed

ΔHºrxn = ( 1652 + 972 ) kJ - ( 1356 + 1708 ) kJ

= 2624 kj - 3064 kJ

= - 440 kJ

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Andre45 [30]

Answer:

$K^{+}$ and $NO_{3}^{-}$

Explanation:

The equation for the reaction is AgNO3(aq) + KCl(aq) ==> AgCl(s) + KNO3(aq)

With all the ions, it is

$Ag^{+}$ (aq) + $NO_{3} ^{-}$ (aq) + $K^{+}$ (aq) + $Cl^{-}$ (aq) ==> AgCl(s) +

$K^{+}$ and $NO_{3} ^{-}$ do not change, so they are the spectator ions and are removed

The ionic equation is:

$Ag^{+}$ (aq) + $Cl^{-}$ (aq) ==> AgCl(s)

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3 years ago

Limit sodium intake to less than ____________ per day. Limit saturated fat intake to less than ____________ of daily kilocalorie

kotykmax [81]

Answer:

Limit sodium intake to less than 2,300mg per day. Limit saturated fat intake to less than 10% of daily kilocalories. Limit intake of added sugars to less than 5% of daily kilocalories. Limit intake of alcohol to less than 3 drinks per day for men or less than 2 drinks per day for women.

Explanation:

The human body has been designed such that there are dietary requirements and benefits these intakes give the body. However, excess consumption of certain foods, could be far more detrimental both on the short and long run.

Sodium is majorly consumed in the form of salt (Sodium chloride). When eaten in the right quantity, it serves as an electrolyte which maintains fluid balance in the body however, when taken in excess, it pulls too much fluid, leading to high blood pressure. The recommended salt intake therefore, is less than 2,300mg daily.

Saturated fat when consumed, is a good source for the body to convert diet to energy, keeping the blood sugar levels constant. Lard, fatty meats are examples of saturated fat. However, when consumed in large amounts, saturated fats can cause cholesterol build up in blood vessels, increasing the risk of heart disease. Its intake should therefore be limited to less than 10% of daily kilocalories.

Added sugars are sources of energy to the body however, when taken in large amounts, could impede normal metabolism in the body. Added sugars should be restricted to less than 5% of daily kilocalories in diet.

Alcohol intake such as in wine, when done in moderation, has been shown to reduce the risk of heart diseases. However, when taken in excess, tolerance builds and exposes the body to the risk of conditions such as liver disease, alcohol use disorder.

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4 years ago

A 0.200 g sample of unknown metal x is dropped into hydrochloride acid and realeases 80.3 mL of hydrogen gas at STP using ideal

s344n2d4d5 [400]

Answer:

The number of mole of the unknown metal is 3.58×10¯³ mole

Explanation:

We'll begin by calculating the number of mole hydrogen gas, H2 that will occupy 80.3 mL at stp.

This is illustrated below:

Recall:

1 mole of any occupy 22.4L or 22400 mL at stp.

1 mole of H2 occupies 22400 mL at stp.

Therefore, Xmol of H2 will occupy 80.3 mL at stp i.e

Xmol of H2 = 80.3/22400

Xmol of H2 = 3.58×10¯³ mole

Therefore, 3.58×10¯³ mole of Hydrogen gas was released.

Now, we can determine the mole of the unknown metal as follow:

The balanced equation for the reaction is given below:

X + 2HCl —> XCl2 + H2

From the balanced equation above,

1 mole of the unknown metal reacted to produce 1 mole of H2.

Therefore, 3.58×10¯³ mole of the unknown metal will also react to produce 3.58×10¯³ mole of H2.

Therefore, the number of mole of the unknown compound is 3.58×10¯³ mole.

5 0

3 years ago

Determine whether each molecule given below is polar or nonpolar. of2

sergejj [24]

Answer : The molecule $OF_2$ is a polar molecule.

Explanation :

Polar molecule : When the arrangement of the molecule is asymmetrical then the molecule is polar.

Non-polar molecule : When the arrangement of the molecule is symmetrical then the molecule is non-polar.

The given molecule is, $OF_2$

The electronegativities of oxygen and fluorine are different. The molecular geometry of $OF_2$ is bent. As, Fluorine is more elctronegative than the oxygen. So, the arrows putting towards the more electronegative element i.e, fluorine. These arrows do not balance each other. Due to this, the asymmetrical arrangement of these bonds makes the molecule polar.

Hence, the given molecule $OF_2$ is polar.

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IrinaVladis [17]

Answer:

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