The transition state's energy is higher than either the reactants or products. Hence, the activation energy is always positive, irrespective of whether the reaction proceeds forward or backward. The activation energy is the energy difference between the transition state and the reactants for a forward react
In all cases, an energy barrier must be overcome before a reaction can take place, regardless of whether the energy changes that emerge from a reaction are positive, negative, or even zero. This indicates that there is still positive energy for activation. Negative' in terms of numerical value as the rate of reaction increases with temperature therefore the products formation is always more than that of reactants. Thus activation energy i.e the minimum energy required to get reactants converted into products is always positive. Endothermic reactions have greater activation energy of the forward reaction than the reverse reaction because the products of this reaction have more energy than the reactants. We know endothermic reactions require energy/heat this energy is required to overcome the greater energy barrier. Simple physics suggests that when you put more heat into the climate system, land should warm more quickly than oceans. This is because land has a smaller “heat capacity” than water, which means it needs less heat to raise its temperature. Land surfaces absorb much more solar radiation than water. Water reflects most solar radiation that reaches its surface back to the atmosphere. Since land absorbs more solar radiation the land surface retains more heat as do the vegetation for energy. Thus, land surfaces warm more quickly than water. For water, this amount is one calorie, or 4.184 Joules. As a result, it takes water a long time to heat and a long time to cool. In fact, the specific heat capacity of water is about five times more than that of sand. This explains why the land cools faster than the sea. Water has about four times higher heat capacity than land, i.e. it takes much more energy to increase the water temperature and the water temperature will therefore respond slower to temperature changes. It takes less energy to change the temperature of land compared to water. This means that land heats and cools more quickly than water and this difference affects the climate of different areas on Earth. Different energy transfer processes also contribute to different rates of heating between land and water.