Purpose
prediction
procedure
data
calculation
conclusion - results etc.
Answer:
3.6mol Li
Explanation:
To get the amount of moles from the mass we divide the mass by the molar mass.
25g ÷ 6.941g/mol = 3.6mol Li
The original sample was a compound because it was composed of two different elements and was not purely one element
As the reaction speed involves the overcoming of the activation energy (due to a required amount of kinetic energy between the particles). When temperature is increased it will provide more energy for the movement of the particles to gain more kinetic energy meaning the rate at which the particles interact increase
1. Endothermic reaction
2. Exothermic reaction
3. Exothermic reaction
<u>Explanation:</u>
1. Evaporation of alcohol from the skin, here the heat is absorbed by the alcohol so that it gets evaporated from the skin and it is an endothermic process. As the reaction says that, the energy is added to the system, so it is endothermic.
C₃H₈O + 5.2 kJ → C₃H₈O(g)
2. Burning of propane in a gas grill:
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O + 1652 kJ.
Here energy is released or given out which is termed as exothermic reaction.
3. Oxidation of iron to form rust:
4 Fe + 3O₂ → 2 Fe₂O₃ + 2221 kJ.
Here also energy is released along with the products, so it is termed as exothermic reaction.
Whenever energy is absorbed, the reaction is endothermic in contrast if the energy is released then the reaction is exothermic.
