Polycarbonate plastic has a density of 1.2 g/cm3. A photo frame is constructed from
two 5.2 mm sheets of polycarbonate. Each
sheet measures 22 cm by 20 cm.
What is the mass of the photo frame?

The mass of the photo frame : = 549.12 g

Given

a photo frame

two 5.2 mm sheets = 0.52 cm

22 cm by 20 cm dimension

Required

the mass

Solution

The volume of one sheet = l x w x h

= 22 cm x 20 cm x 0.52 cm

= 228.8 cm³

Mass of one sheet :

= density x volume

= 1.2 g/cm³ x 228.8 cm³

= 274.56 g

So for two sheets of polycarbonate :

= 2 x  274.56 g

= 549.12 g

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = = 298 k

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

according to reaction 3 moles no are reacting with 1 mol of ,then 0.49 mol of no will react with moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :