5.10.2 Heat Change in Chemical Reaction

A chemical is dissolved in a glass of water and the temperature of the water decreases. Which of the following is likely the chemical dissolve in the water?

Which of the following are endothermic reactions?
I. Combustion of fuel
II. Dissolving ammonium chloride salt in water
III. Decomposition of calcium carbonate by heat
IV. Dissolving sodium hydroxide in water

Which of the followings are true about an exothermic reaction?
I. Energy is released during the reaction.
II. Light is absorbed during the reaction.
III. The products of the reaction have less chemical energy than the reactants.
IV. The temperature of the products will be lower than the reactants.

Which of the followings are true about an endothermic reaction?
I. Heat is absorbed from the surrounding.
II. The products have higher energy than the reactants.
III. The temperature of the products is higher than the reactants.
IV. Heat energy is needed to initiate the reaction.

Which of the following explain why a temperature of 450°C in chosen as the optimum temperature in Haber process?
I. The reaction will not occur at any temperature higher than 500°C.
II. Lower temperature will slow down the reaction.
III. Reaction at higher temperature will produce less ammonia.
IV. The cost to carry out the reaction at higher temperature is too high.

Contact process is a process used in industry to produce

The catalyst used in contact process is