the reaction is exothermic and the ΔH is negative. Therefore, the system’s
surroundings must gain the energy that the system loses so that energy is
conserved.
CONSERVATION OF MASS AND ENERGY
With the introduction of atomic theory and a more complete understanding of the
nature of both mass and energy, it was found that a relationship exists between
these two concepts. Einstein formulated the Law of Conservation of Mass and
Energy. This states that mass and energy are interchangeable under special
conditions. The conditions have been created in nuclear reactors and
accelerators, and the law has been verified. This relationship can be expressed by
Einstein’s famous equation:
SCIENTIFIC METHOD
Although some discoveries are made in science by accident, in most cases, the
scientists involved use an orderly process to work on their projects and
discoveries. The process researchers use to carry out their investigations is often
called the scientific method. It is a logical approach to solving problems by
observing and collecting data, formulating a hypothesis, and constructing theories
supported by the data. The formulating of a hypothesis consists of carefully
studying the data collected and organized to see if a testable statement can be
made with regard to the data. The hypothesis takes the form of an “if... then”
statement. If certain data are true, then a prediction can be made concerning the
outcome. The next step is to test the prediction to see if it withstands the
experimentation. The hypothesis can go through several revisions as the process
continues. If the data from experimentation show that the predictions of the
hypothesis are successful, scientists usually try to explain the phenomena by
constructing a model. The model can be a visual, verbal, or mathematical means
of explaining how the data is related to the phenomena.
The stages of this process can be illustrated by the diagram shown below: