Please help i have a midterm tommorow
1 answer:
A polar bond is formed with atoms having different electronegativities. The bonding electrons are attracted more towards the atom with greater electronegativity resulting in unequal sharing of electrons. Therefore the molecule develop partial charges and becomes polar. Polar molecules have dipole moment that is the partial charge on molecules due to differences in electronegativity between atoms.
A non-polar bond is formed with atoms having the same electronegativity, hence the bonded pair of electron is shared equally between atoms. Non-polar molecules have no moment.
Note that: symmetrical molecules having polar bonds are non-polar because the dipoles of the bond exert equal and opposite effect. Hence the dipoles cancel the charges.
Example: HCl
In HCl, Cl is more electronegative therefore Cl atom pulls the electron pair of the covalent bond towards itself and develops a partial negative charge. Consequently H develops a partial positive charge. This therfore leads to the formation of a dipole.
A non-polar bond is formed with atoms having the same electronegativity, hence the bonded pair of electron is shared equally between atoms. Non-polar molecules have no moment.
Note that: symmetrical molecules having polar bonds are non-polar because the dipoles of the bond exert equal and opposite effect. Hence the dipoles cancel the charges.
Example: HCl
In HCl, Cl is more electronegative therefore Cl atom pulls the electron pair of the covalent bond towards itself and develops a partial negative charge. Consequently H develops a partial positive charge. This therfore leads to the formation of a dipole.
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<u>Answer:</u> The enthalpy of the reaction is -4134.3 kJ/mol
<u>Explanation:</u>
To calculate the heat absorbed by the calorimeter, we use the equation:
where,
q = heat absorbed
m = mass of calorimeter = 1.900 kg = 1900 g (Conversion factor: 1 kg = 1000 g)
c = heat capacity of calorimeter = 3.21 J/g.K
= change in temperature = 4.542 K
Putting values in above equation, we get:
Heat released by the calorimeter will be equal to the heat absorbed by the reaction.
<u>Sign convention of heat:</u>
When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.
To calculate the number of moles, we use the equation:
Given mass of hexane = 0.580 g
Molar mass of hexane = 86.18 g/mol
Putting values in above equation, we get:
To calculate the enthalpy change of the reaction, we use the equation:
where,
q = amount of heat released = -27.7 kJ
n = number of moles of hexane= 0.0067 moles
= enthalpy change of the reaction
Putting values in above equation, we get:
Hence, the enthalpy of the reaction is -4134.3 kJ/mol