Question

# solarcaine aerosol spray is used for temporarily relieving pain as it works as a topical anesthetic...

solarcaine aerosol spray is used for temporarily relieving pain as it works as a topical anesthetic numbing the skin. Solarcaine is in fact benzocaine, C9H11NO2 with molar mass 165.2g/mol. If a 100 ml spray contains 1.00g of benzocaine, calculate the pressure within the can and explain why it is likely to explode when heated in a fire where the tempreature maybe as high as 1300 degress celcuis.

Given volume of benzocaine , V = 100 mL = 0.1 L

mass of benzocaine , m = 1.00 g

molarmass of benzocaine , M = 165.2 g/mol

number of moles of benzocaine , n = mass/molarmass

= 1.0 / 165.2 g/mol

= 6.05x10-3 g/mol

Temperature , T = 1300 oC = 1300 +273 K

= 1573 K

We know that PV = nRT    R - gas constant = 0.0821 Latm/mol-K

So P = nRT / V

= (6.05x10-3 x 0.0821 x 1573 ) / 0.1

= 7.81 atm

So the pressure within the can is 7.81 atm

At high temperature the vibrational energy of the molecules will be more thereby it cannot inbuilt in the can & the molecules came out resulting explosion.