Acarnot engine operates between a hot reservoir temperature of 215 degrees c and a cold reservoir temperature of 20 degrees c. if the engine draws 1000 j from the hot reservoir per cycle, how much work will it do per cycle?

a, 1000 j
b, 100 j
c, 400 j
d, 600 j
e, 900 j

c. 400 J

Explanation:

The efficiency of a Carnot Engine is given by:

where in this case we have

is the temperature of the cold reservoir

is the temperature of the hot reservoir

Substituting into the equation,

But the efficiency can also be written as

where

is the useful work in output

is the heat absorbed by the hot reservoir

Here,

So solving the formula for we find

gets less

  the grams     of oxygen gas   that can be produced     is 20.6   grams of o₂

calculation

2liclo₃ →   2 licl + 3 o₂

step 1:   find the moles of liclo₃

moles = mass÷ molar mass

from periodic table the molar mass of liclo₃ =6.9 +35.5   +(16 x3) =90.4 g/mol

moles=38.7 g÷90.4 g/mol=0.4281   moles

step 2:   use the   mole ratio   to calculate the moles of o2

from equation above, liclo₃: o₂   is 2: 3  

therefore the moles of   o₂=0.4281 moles x3/2 =0.6422   moles

step 3: find mass   of o₂

mass= moles x molar mass

from periodic table the   molar mass of   o₂ = 16 x2= 32 g/mol

mass=0.6422   moles   x   32 g/mol = 20.6 grams of o₂