Thermochemistry is the study of the energy changes that occur during chemical reactions and physical processes. Delta H and q of surroundings are two ways of measuring these energy changes, with delta H representing the change in enthalpy and q of surroundings representing the heat gained or lost by the surroundings.
Delta H can be calculated by subtracting the enthalpy of the products from the enthalpy of the reactants in a chemical reaction. Q of surroundings can be calculated using the formula q = m x c x delta T, where m is the mass of the surroundings, c is the specific heat capacity, and delta T is the change in temperature.
Delta H and q of surroundings provide information about the energy changes that occur during a chemical reaction. A negative delta H or a negative q of surroundings indicates an exothermic reaction, meaning energy is released to the surroundings. A positive delta H or a positive q of surroundings indicates an endothermic reaction, meaning energy is absorbed from the surroundings.
The magnitude of delta H and q of surroundings can affect the rate of a reaction. A higher energy release (negative delta H or q of surroundings) can increase the rate of an exothermic reaction, while a higher energy absorption (positive delta H or q of surroundings) can increase the rate of an endothermic reaction. This is because a higher energy change means more energy is available to fuel the reaction.
Delta H and q of surroundings can provide information about the direction of a reaction. A negative delta H or q of surroundings indicates a spontaneous reaction, meaning it is likely to occur in the forward direction. A positive delta H or q of surroundings indicates a non-spontaneous reaction, meaning it is likely to occur in the reverse direction. However, other factors such as entropy must also be considered to accurately predict the direction of a reaction.