For example, people who have been drug free for a decade can experience cravings when returning to an old neighborhood or house where they used drugs like riding a bike, the brain remembers why are drugs more addictive than natural rewards. Start studying science chapter 17 - section 2 learn vocabulary, terms, and more with flashcards, games, and other study tools the mass of all substabces before a chemical change equals the mass of all substances after a chemical change characteristics of a substance indicating that it can change chemically for example, flammability.
All substances have distinct physical and chemical properties, and may undergo physical or chemical changes physical properties, such as hardness and boiling point, and physical changes, such as melting or freezing, do not involve a change in the composition of matter. Over the last several decades, research on substances of abuse has vastly improved our understanding of human behavior and physiology and the nature of substance abuse and dependence basic neurobiological research has enhanced our understanding of the biological and genetic causes of addiction. Substance abuse and causes a pattern of drug use that diminishes one's ability to fulfill responsibilities at home, work, or at school, that resuslts in repeated use of a drug in dangerous situations, or that leads to legal difficulties related to drug use.
Chemical properties: these properties enable a substance to change into a brand-new substance, and they describe how a substance reacts with other substances does a substance change into something completely new when water is added — like sodium metal changes to sodium hydroxide. Behavioral addiction versus substance addiction: correspondence of psychiatric and psychological views contrary to the commonly held belief that holds addiction to be a particular kind of dependence on drugs and chemical substances such alcohol, nicotine and heroin, behavior science experts believe that any source which is. As drug dependency begins to take a physical hold on a dependent individual, personality changes can occur illegal drugs begin to affect brain function—including the areas regulating cognition and mood—by altering chemical messengers in the brain known as neurotransmitters.
Exposure to a psychoactive substance can cause changes in the structure and functioning of neurons, as the nervous system tries to re-establish the homeostasis disrupted by the presence of the drug (see also, neuroplasticity.
According to this definition a chemical substance can either be a pure chemical element or a pure chemical about 80 of which are stable – that is, they do not change by radioactive decay into other elements some elements can occur as more than a single chemical substance for instance, oxygen exists as both diatomic oxygen.