Flashcards in C3a Deck (9):
What is an exothermic reaction?
-energy is given out to the surroundings
-usually a form of heat, which is shown by a rise in temperature
What is an endothermic reaction?
-energy is taken in from surroundings
-usually in the form of heat, which is shown by a fall in temperature
How can you decide if reaction is exo or endo?
-in a chemical reaction you can tell by taking temperature of reactants, mixing them in polystyrene cup and measuring the temperature of the solution
Give examples of endothermic reaction?
-adding acid to an alkali
Give examples of exothermic reactions?
-dissolving ammonium nitrate in water
What is the relation between bonds and endothermic reaction?
-the energy required to break bonds is greater than the energy released when new bonds are formed
What is the relation between bonds and exothermic reactions?
-energy released in bond formation is greater than the energy used to break old bons
How can you calculate energy transferred?
-you can calculate energy supplied per gram of fuel if you know:
*how much fuel you burnt
*temperature change of water
*mass of water
-doing the same experiment with different fuels allows you to compare the energy transferred per gram