A characteristic which helps an animal to live longer will generally tend to become more common in the population because as the animal produces more offspring those traits are passed down to them. Eventually it will be a common characteristic in the population.
Hope that helped :)
To determine the heat required in order to decompose a certain amount of a substance, we need information on the heat needed to decompose one mole of the substance. This value are readily available online and other sources. For this reaction, the heat needed is 129 kJ per 2 mol of NaHCO3. We calculate as follows:
129 KJ / 2 mol NaHCO3 (1 mol / 84.01 g ) (25.5 g NaHCO3 ) = 19.58 kJ of heat is needed.
There are two reasons that account for the change in concentration. One is by the physical change and second is by the chemical change. The physical change refers to the mixture of the two compounds. The concentration is the amount of that certain substance to the whole mixture. Since the mixture increases because you add them up, the concentration decreases. Second, these compounds react with each other once they interact. Hence, their amounts would be consumed in order to produce the products.