All categories

3 years ago

Given the standard enthalpy changes for the following two reactions:

Chemistry

2 answers:

koban [17]3 years ago

8 0

Answer:

ΔH° = -186.2 kJ

Explanation:

Step 1: Data given

(1) Sn(s) + Cl2(g) ⇆ SnCl2(s) ΔH° = -325.1 kJ

(2) Sn(s) + 2Cl2(g) ⇆ SnCl4(l) ΔH° = -511.3 kJ

Step 2: The balanced equation

SnCl2(s) + Cl2(g) ⇆ SnCl4(l)

Step 3: Calculate the standard enthalpy change for the reaction

We have to take the reverse equation of the first reaction ( Because we need SnCl2 as reactant)

SnCl2(s) ⇆ Sn(s) + Cl2(g) ΔH° = 325.1 kJ

Then we add the second equation to this new one

SnCl2(s) ⇆ Sn(s) + Cl2(g) ΔH° = 325.1 kJ

Sn(s) + 2Cl2(g) ⇆ SnCl4(l) ΔH° = -511.3 kJ

SnCl2(s) + Sn(s) + 2Cl2(g) ⇆ Sn(s) + Cl2(g) + SnCl4(l)

SnCl2(s) + Cl2(g) ⇆ SnCl4(l)

ΔH° = 325.1 kJ + (-511.3kJ)

ΔH° = 325.1 kJ - 511.3 kJ

ΔH° = -186.2 kJ

lawyer [7]3 years ago

7 0

Answer:

ΔH° = -186.2 kJ

Explanation:

Hello,

This case in which the Hess method is applied to compute the required chemical reaction. Thus, we should arrange the given first two reactions as:

(1) it is changed as:

SnCl2(s) --> Sn(s) + Cl2(g)...... ΔH° = 325.1 kJ

That is why the enthalpy of reaction sign is inverted.

(2) remains the same:

Sn(s) + 2Cl2(g) --> SnCl4(l)......ΔH° = -511.3 kJ

Therefore, by adding them, we obtain the requested chemical reaction:

(3) SnCl2(s) + Cl2(g) --> SnCl4(l)

For which the enthalpy change is:

ΔH° = 325.1 kJ - 511.3 kJ

ΔH° = -186.2 kJ

Best regards.

You might be interested in

A 20.0-milliliter sample of 0.200 M K2CO3 solution is added to 30.0 milliliters of 0.400 M Ba(NO3)2 solution.

jenyasd209 [6]

Answer:

(B) 0.160 M

Explanation:

Considering:

$Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}$

Or,

$Moles =Molarity \times {Volume\ of\ the\ solution}$

Given :

For $K_2CO_3$ :

Molarity = 0.200 M

Volume = 20.0 mL

The conversion of mL to L is shown below:

1 mL = 10⁻³ L

Thus, volume = 20.0×10⁻³ L

Thus, moles of $K_2CO_3$ :

$Moles=0.200 \times {20.0\times 10^{-3}}\ moles$

Moles of $K_2CO_3$ = 0.004 moles

For $Ba(NO_3)_2$ :

Molarity = 0.400 M

Volume = 30.0 mL

The conversion of mL to L is shown below:

1 mL = 10⁻³ L

Thus, volume =30.0×10⁻³ L

Thus, moles of $Ba(NO_3)_2$ :

$Moles=0.400\times {30.0\times 10^{-3}}\ moles$

Moles of $Ba(NO_3)_2$ = 0.012 moles

According to the given reaction:

$K_2CO_3_{(aq)}+Ba(NO_3)_2_{(aq)}\rightarrow BaCO_3_{(s)}+2KNO_3_{(aq)}$

1 mole of potassium carbonate react with 1 mole of barium nitrate

0.004 moles potassium carbonate react with 0.004 mole of barium nitrate

Moles of barium nitrate = 0.004 moles

Available moles of barium nitrate = 0.012 moles

Limiting reagent is the one which is present in small amount. Thus, potassium carbonate is limiting reagent.

The formation of the product is governed by the limiting reagent. So,

1 mole of potassium carbonate gives 1 mole of barium carbonate

Also,

0.004 mole of potassium carbonate gives 0.004 mole of barium carbonate

Mole of barium carbonate = 0.004 moles

Also, consumed barium nitrate = 0.004 moles (barium ions precipitate with carbonate ions)

Left over moles = 0.012 - 0.004 moles = 0.008 moles

Total volume = 20.0 + 30.0 mL = 50.0 mL = 0.05 L

So, Concentration = 0.008/0.05 M = 0.160 M

<u>(B) is correct.</u>

4 0

3 years ago

Is the asthenosphere or the lithosphere closer to the outer core

Murrr4er [49]

The asthenosphere is directly below the lithosphere so the answer to your question is the asthenosphere, because the outer core is towards the center of Earth.

4 0

3 years ago

Sam believes the rock is more denser than the pencil. He measured the mass of the rock to be 8.5 grams and volume to be 4.5mL. H

mezya [45]

Answer:

Rock

Explanation:

Let's calculate the density of each object:

Rock:

$Density = \frac{mass}{volume}=\frac{8.5\ g}{4.5\ mL}=1.9\ g/mL$

Pencil:

$Density = \frac{mass}{volume}=\frac{2.4\ g}{4.5\ mL}=0.53\ g/mL$

Therefore the rock is denser.

6 0

2 years ago

Photosynthesis can be represented by6CO2(g)+6H2O(l)⇌C6H12O6(s)+6O2(g)Which of the following will be false when the photosynthesi

denis-greek [22]

Answer:

The concentration of O2 will begin decreasing and The concentrations of CO2 and O2 will be equal.

Explanation:

Equilibrium occurs when the velocity of the formation of the products it's equal to the velocity of the formation of the reactants, thus the concentrations of the compounds remain constant.

Analyzing the information and the reaction given, we can notice that in equilibrium the rate (velocity) of formation of O2 (product) is equal to the rate of formation of CO2 (reactant).

As the CO2 and H2O are placed in the reaction, the Le Chateliêr's principle states that the equilibrium must shift to reestablish the equilibrium, thus, they must be consumed, and the concentration of O2 must increase.

As state above, in equilibrium, the concentrations didn't change, thus, the concentrations of CO2 and O2 will not change.

The concentrations of CO2 and O2 depends on the rate of the reaction and the initial quantities presented, so it's not possible to affirm they'll be equal.

8 0

3 years ago

Calculate the mass, in grams, of 122 atoms of iron, Fe (1 mol of Fe has a mass of 55.85 g).

vitfil [10]

Answer:

6813.7g

Explanation:

Calculate the mass

Let x be the mass

If 1 mol of Fe has a mass of 55.85 g

1 mol =55.85g

122mol= x

we have x= 122•55.85g=6813.7g

7 0

2 years ago