Question | Answer |
Ductility | to pull a substance, typically a metal, into a thin wire |
Reactivity | substance to chemically react with other substances |
Malleability | substance to be hammered or pounded into a thin sheet |
Density | substance in a given volume, determines if objects will float or sink when combined physically. |
Solubility | substance to dissolve in another |
Flammability | substance to burn |
Mass | amount of matter in an object |
Volume | amount of space an object occupies |
Chemical Property | changes that are possible for a substance |
Chemical Change | process by which new substances are formed |
Temperature | average kinetic energy of the molecules in a substance, how fast the molecules are moving. |
conduction | transfer of heat by direct contact between objects |
convection | The transfer of heat through waves, does not require direct contact between objects. |
How does a physical change differ from a chemical change? | physical change- changed without change its chemical composition Chemical change- involves a chemical reaction |
What are the signs that indicate that a chemical change has happened | color change. gas production. release of heat. light. odor. sound |
What happens to the particles of a liquid when it becomes a gas | gain energy and break away from each other. |
What measurement is the same as the melting point of a substance | freezing point, they are opposites. |
Carbon dioxide gas can enter the air from dry ice. What has to happen to the dry ice | dry ice must gain energy to cause the molecules to increase in speed, forming the gas |
Railroad tracks have gaps between the rails so that they will not buckle in hot weather. What would cause the rails to buckle | thermal expansion of the metal the tracks are made of could cause them to buckle in hot weather. |
What does heat do to particles during a chemical reaction | Heat breaks the original bonds between particles and creates new bonds during a chemical reaction |
What is absolute zero (the values and the definition | Absolute zero is 0°K, it is the point where molecules of a substance stop moving. |
What happens to thermal energy when a substance changes state | Thermal energy changes the temperature of the substance |
Explain the difference between an insulator and conductor | Insulators do not allow heat and electric current to flow easily - conductors allow the transfer of heat |
What did Democritus, Dalton, Thomson, Rutherford, and Bohr all have in common | contributed to The Atomic Theory |
In Thomson’s “plum-pudding” model of the atom, the plums ¬represent which subatomic particle | electrons |
Which of the subatomic particle has the least mass | Electrons |
How did Democritus describe atoms | Small, hard, indivisible |
What is the smallest particle into which an element can be divided and still be the same substance | atom |
Which subatomic particle is negatively charged? Where is this particle located in the atom? | Electrons. found in electron clouds |
Which subatomic particle is positively charged? Where is this particle located in the atom? | Protons. found in nucleus |
Which subatomic particle has no charge? Where is this particle located in the atom? | Neutrons found in nucleus |
What do we call the dense center of the atom? | nucleus |
How do elements join to form compounds | a specific recipe for each compound |
What is a pure substance made of two or more elements that are chemically combined | compound |
How is a compound different from a mixture? | Compounds are formed when two or more original substances lose their properties to chemically form a new substance |
When elements form mixtures do the elements form a new substance or keep their original properties | Elements in a mixture are not chemically combined so they keep their original properties |
What type of change forms a compound | Compounds must be combined by a chemical change |