AFOQT Physical Science Exam Questions and Answers All Correct

AFOQT Physical Science Exam Questions and Answers All Correct The lowest possible temperature - Answer-Absolut Zero The pressure exerted by the gases in the air. units of measurement are kilopascals, atmospheres, millimeters of mercury, and Torr - Answer-atmospheric Pressure Pressure is 100 kPa, 1atm, 760 mm Hg or 760 Torr - Answer-standard atmospheric pressure the smallest particle of an element a nucleus and its surrounding electrons. - Answer- Atom the mass of an atom measured in atomic mass units (amu). an atomic mass unit is equal to one-twelfth of the atom of carbon-12. atomic mass is now more generally used instead of atomic weight. Example: the atomic mass of chlorine is about 35amu. - Answer-atomic mass also known as proton number, it is the number of electrons or the number of protons in an atom. example: the atomic number of gold is 79. - Answer-atomic number a common term used to mean the average molar mass of an element. this is the mass per mole of atoms. Ex: the atomic weight of chlorine is about 35g/mol - Answer-atomic weight the temperature at which a substance undergoes a phase change from a liquid to a gas. - Answer-boiling point. a temperature scale on which the freezing point of water is at 0 degrees and the normal boiling point at standard atmospheric pressure is 100 degrees. - Answer-celsius scale a change between two of the three states of matter, solid, liquid and gas. example when water evaporates t changes from a liquid to a gaseous state. - Answer-change of state. a chemical consisting of two or more elements chemically bonded together. example: calcium can combine with carbon and oxygen to make calcium carbonate a compound of all three elements. - Answer-compound the formation of a liquid from a gas. this is a change of state, also called a phase change. - Answer-condensation the exchange of heat (heat conduction) by contact with another object, or allowing the flow of electrons (electrical conduction) - Answer-conduction the exchange of heat energy with the surroundings produced by the flow of a fluid due to being heated or cooled. - Answer-convection the way that a radioactive element changes into another element due to loss of was through radiation. Example: uranium 238 decays with the loss of an alpha particle to form thorium 234. - Answer-decay the mass per unit volume - Answer-density to break down a substance in a solution without causing a reaction - Answer-dissolve the energy produced by an electrochemical cell and measured by the voltage or electromotive force. - Answer-electrical potential a tiny, negatively charged particle that is part of an atom. the flow of electrons through a solid material such as a wire produces an electric current. - Answer-electron a substance that cannot be decomposed into simpler substance by chemical means. examples: calcium, iron, gold - Answer-element a substance which when a shock is applied to it, decomposes very rapidly, releasing a very large amount of heat and creating a large volume of gases as a shock wave. - Answer-explosive able to flow either liquid or a gas - Answer-fluid the temperature at which a substance undergoes a phase change from a liquid to a solid. it is the same temperature as the melting point. - Answer-freezing point. waves of radiation produced as a nucleus of a radioactive element rearranges itself into a tighter cluster of protons and neutrons. carry enough energy to damage living cells. - Answer-gamma rays a form of matter in which the molecules form no definite shape, and are free to move about to uniformly fill any vessel they are put in. a gas can easily be compressed into a much smaller volume. - Answer-gas a vertical column in the periodic table there are eight groups in the table. their numbers correspond to the number of electrons in the outer shell of the atoms in the group. example: Group 2 contains Beryllium, magnesium, calcium, strontium, barium, and radium. - Answer-Group the time it takes for the radiation coming from a sample of a radioactive element to decrease by half. - Answer-half-life the energy that is transferred when a substance is at a different temperature to that of its surroundings. - Answer-heat the ratio of the heat supplied to a substance compared with the rise in temperature that is produced. - Answer-heat capacity the amount of heat given off by a mole of a substance during combustion this heat is a property of the substance and is the same no matter what kind of combustion is involved. - Answer-heat of combustion an atom, or group if atoms that has gained or lost one or more electrons and so developed an electrical charge. ions behave differently from electrically neutral atoms and molecules. the can move in an electric field. and they can also bind strongly to solvent molecules such as water. positively charged ions are called cations, negatively charged ions are called anions. ions can carry an electrical current through solutions. - Answer-ion