As a gasoline engine is running, an amount of gasoline containing 15,000J of chemical potential energy is burned in 1 s. During that second, the engine does 3,000 J of work. (b) The burning gasoline has a temperature of about 2500 K. The waste heat from the engine flows into air at about 300 K. What is the Carnot efficiency of a heat engine operating between these two temperatures

,

Explanation:

The Carnot efficiency is the maximum theoretical efficiency that a thermal machine can reach, the expression is:

The real efficiency of the engine is:

Real efficiency of the engine must be lower than maximum theoretical efficiency due to irreversibilities.

whichever one it is, it's definitely not one that you included on the list you provided.

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz