Many power plants produce energy by burning carbon-based fuels, which also produces carbon dioxide. carbon dioxide is a greenhouse gas, so over-production can have negative effects on the environment. use enthalpy of formation data to calculate the number of moles of co2(g) produced per megajoule of heat released from the combustion of each fuel under standard conditions (1 atm and 25 °c).

2.54 mol CO2

Explanation:

To calculate the mol of carbon dioxide that will be generated by megajoule (MJ). First, we have to find the value of the formation enthalpy for the CO2 at standard conditions.

Remember that standard conditions are at 25°C and 1 atm.

Any physic chemistry book has the table of ΔHf°, I always use one name Levine's physic chemistry. You can trust its data.

Enthalpy of formation for CO2: -393.509 kJ/mol

As you can see this value means that for each 393.509 kJ liberate (that's indicated for the menus sing),  1 mol of CO2 is formed.

Let's write this using mathematic language:

393.509 kJ/ 1 mol CO2

The problem asks you to find how many mols are produced by 1 megajoule liberate, let's change megajoule to kilojoule.

1 megajoule (MJ) = 1000 kJ

1000 kJ x (1mol/ 393.509 kJ) = 2.54 mol CO2  

Remember don't use the negative value to make the calculus. The negative value just indicates that the heat is been released.

If you want to watch the mathematics details, go to the image attached.

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.