Chapter 2 - Chemistry Flashcards
Identify mass number and atomic mass.
Mass number is the total number of protons and neutrons in an atomic nucleus.
Atomic mass is the total mass of protons, neutrons, and electrons in a given element.
What are compounds and their physical and chemical properties?
A compound is a substance formed by the chemical combination of two or more elements in definite proportions. Their physical and chemical properties are usually very different from those of the elements from which it is formed.
What are isotopes and what are the uses of radioactive isotopes?
Isotopes are atoms of elements with different number of neutrons. Radioactive isotopes have many useful applications. In medicine, for example, cobalt-60 is employed as a radiation source to halt the development of cancer. Other radioactive isotopes are used as tracers for diagnostic purposes as well as in research on metabolic processes.
What is activation energy?
Activation energy is the energy needed to get a reaction started.
What are valence electrons?
Valence electrons are electrons that are available to bond.
What is a chemical reaction?
A chemical reaction is a process that changes or transforms one set of chemicals into another.
What are enzymes and catalysts?
A catalyst is a substance that speeds up the rate of a chemical reaction. They lower the reaction’s activation energy. Enzymes are proteins that act as biological catalysts.
What are ionic and covalent bonds?
An ionic bond is formed when one or more electrons are transferred from one atom to another. In a covalent bond, electrons are shared rather than transferred.
What are atoms composed of?
Atoms are made up of 3 subatomic particles: electrons, ( - ) protons, ( + ) and neutrons. Strong forces bind the protons and neutrons together to form the nucleus in the center. Electrons are in constant motion and are attracted to protons.
What are macromolecules?
Macromolecules are giant molecules that are a formed in a process known as polymerization, in which monomers join together to form polymers. Carbohydrates are macromolecules. They are compounds made up of carbon, hydrogen, and oxygen atoms usually in a ratio of 1:2:1. Living things use carbohydrates as their main source of energy. Lipids, such as fats and waxes, are also macromolecules. Lipids store energy and are important parts of biological membranes and waterproof coverings. Next, nucleic acids store genetic data. Finally, proteins regulate cell processes.
What is density?
Density is a measure of how much matter occupies a given amount of space. An ice cube floats in water because the ice is less dense than the water.
What is the importance of Carbon?
Living things need carbon in order to live, grow, and reproduce. Carbon is a finite resource that cycles through the Earth in many forms. This makes carbon available to living organisms and remains in balance with other chemical reactions in the atmosphere and in bodies of water like ponds and oceans.
What are the different types of ions, why do they form?
Anions are negatively charged ions. Anions are negatively charged because there are more electrons associated with them than there are protons in their nuclei.
Cations are positively charged ions. Cations are the opposite of anions, since cations have fewer electrons than protons.
Ions are positively or negatively charged particles that form as a result of an atom losing an electron or gaining a proton.
What is the function of valence electrons?
An electron of an atom, located in the outermost shell (valence shell) of the atom, that can be transferred to or shared with another atom. An electron in one of the outer shells of an atom that can participate in forming chemical bonds with other atoms.
What do hydroxide and hydrogen concentrations tell you about pH?
The higher the concentration of hydrogen ions the more acidic.
