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3 years ago

How is hess's law applied in calculating enthalpy

Chemistry

2 answers:

Naddik [55]3 years ago

7 0

Answer: To develop a strategy for the order in which you add the various equations.

Explanation:

In a Hess’s Law problem, you have to develop a strategy for the order in which you add the various equations. hope this helps <3

eimsori [14]3 years ago

3 0

Answer:Hess's law states that the change of enthalpy in a chemical reaction (i.e. the heat of reaction at constant pressure) is independent of the pathway between the initial and final states. ... Hess's law allows the enthalpy change (ΔH) for a reaction to be calculated even when it cannot be measured directly.

Explanation:

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What is the balanced form of the chemical equation shown below?

Svetradugi [14.3K]

Answer:

Explanation:

Double Displacement reaction

Both sides are balanced with option D

3 0

3 years ago

How much energy must be removed from a 94.4 g sample of benzene (molar mass= 78.11 g/mol) at 322.0 K to solidify the sample and

Kay [80]

Answer : The energy removed must be, 29.4 kJ

Explanation :

The process involved in this problem are :

$(1):C_6H_6(l)(322K)\rightarrow C_6H_6(l)(279K)\\\\(2):C_6H_6(l)(279K)\rightarrow C_6H_6(s)(279K)\\\\(3):C_6H_6(s)(279K)\rightarrow C_6H_6(s)(205K)$

The expression used will be:

$Q=[m\times c_{p,l}\times (T_{final}-T_{initial})]+[m\times \Delta H_{fusion}]+[m\times c_{p,s}\times (T_{final}-T_{initial})]$

where,

$Q$ = heat released for the reaction = ?

m = mass of benzene = 94.4 g

$c_{p,s}$ = specific heat of solid benzene = $1.51J/g^oC=1.51J/g.K$

$c_{p,l}$ = specific heat of liquid benzene = $1.73J/g^oC=1.73J/g.K$

$\Delta H_{fusion}$ = enthalpy change for fusion = $-9.8kJ/mol=-\frac{9.8\times 1000J/mol}{78g/mol}=-125.6J/g$

Now put all the given values in the above expression, we get:

$Q=[94.4g\times 1.73J/g.K\times (279-322)K]+[94.4g\times -125.6J/g]+[94.4g\times 1.51J/g.K\times (205-279)K]$

$Q=-29427.312J=-29.4kJ$

Negative sign indicates that the heat is removed from the system.

Therefore, the energy removed must be, 29.4 kJ

3 0

3 years ago

PLZ HURRY

Aliun [14]

Hello.

The answer is: False

The current theory of the formation of our solar system is that the planets formed more or less in their present orbits and they were made balls of gas but they were never comets captured by the sun.

Have a nice day

5 0

3 years ago

Read 2 more answers

A subshell contains eight electrons. Which subshell could it be ?

Mila [183]

D, since it can hold up to 10 electrons

6 0

3 years ago

A weight of 22.25g was obtained when 10-mL of water at 27C was pipet to empty Erlenmeyer flask. What is the volume delivered by

Nimfa-mama [501]

Answer:

the volume delivered by the pipette = 22.32 mL

Explanation:

To calculate this, let us first note that the density of water relates it weight and its volume (density = mass ÷ volume), hence we are going to use density to determine the volume.

Density of water = mass/volume = 0.997 g/ mL

mass = 22.25g

Density = 0.997g/mL

volume = ?

$density = \frac{mass}{volume}\\\therefore volume = \frac{mass}{density}\\volume = \frac{22.25}{0.997}\\volume = 22.32\ mL$

∴ the volume delivered by the pipette = 22.32 mL

<em>Please note that this calculation is based on the fact that the weight of the empty flask has been determined and canceled out.</em>

4 0

3 years ago