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Chapter 7
PS 8th Grade, Chapter 7 Review
Question | Answer |
---|---|
When are chemical properties observable? | Only when a chemical change occurs. (7-4) |
List two examples of chemical change. | Burning and rusting.. 7-4 |
What kinds of properties can be used to describe matter? | Both chemical and physical properties (7-4) |
What is the term for the total set of chemical and physical properties that can be used to describe identify a substance? | characteristic properties (7-4) |
If a substance changes into a new substance with new characteristic properties, what kind of change has occurred? | chemical (7-4) |
List three clues that a chemical change might have occurred. | bubbles forming, light / energy being given off, color change (7-4) |
The only sure sign of chemical change is the formation of _____. | a new substance (7-4) |
What is another name for chemical change? | Chemical reaction (7-4) |
In a chemical reaction, what do the atoms do?? | Rearrange / reconnect in new ways (7-4) |
What do scientists usually use to represent chemical reactions? | chemical equations (7-4) |
In a chemical equation, what represents a substance? | a chemical formula (7-4) |
In a chemical equation, what does the arrow mean? | a chemical reaction is taking place (7-4) |
In a chemical equation, what do formulas on the left side of the arrow represent? | reactants (7-4) |
In a chemical equation, what do formulas on the right side of the arrow represent? | products (7-4) |
Why do scientists balance chemical equations? | to show that they obey the law of conservation of mass (7-4) |
What are the numbers written in front of formulas to balance the chemical equations called? | coefficients (7-4) |
What are three things that can be increased in order to speed up most chemical reactions? | temperature, concentration of substances, and surface area of substances (7-4) |
What kind of changes does not change the identity of the substance? | physical (7-3) |
What kind of change is a state of matter change - physical or chemical? | physical (7-3) |
What happens to a substance during condensation? | Its particles slow down, It loses energy, and changes from a gas to a liquid (7-3) |
What happens to particles when thermal energy is added? | they move faster and their temperature rises (7-3) |
What is the temperature at which particles change from liquid to solid as they lose thermal energy? | freezing point (7-3) |
What is the temperature at which particles change from liquid to gas as they gain thermal energy? | boiling point (7-3) |
What is the change from solid directly to gas (without first becoming liquid) called? | sublimation (7-3) |
Which changes of state are reverses of one another? | melting and freezing; condensation and boiling; sublimation and deposition (7-3) |
What is the process in which one substance mixes evenly with another, such as sugar being stirred into water? | dissolving (7-3) |
What law could be stated in this way: "The particles that are present before a physical or chemical change are also present after the change"? | the law of conservation of mass (7-3) |
What kind of property is "a characteristic that can be observed without changing the identity of the matter?" | physical property (7-2) |
What is the term for the kind of physical property that will have a different measurement if the amount of material changes? | size-dependent (7-2) |
List three examples of size-dependent characteristics? | mass, volume, weight (7-2) |
What is the term for the kind of physical property that will have the same measurement no matter how large the sample is? | size-independent (7-2) |
List three examples of size-independent characteristics? | density, boiling point, freezing point (7-2) |
What is the term for the ability of one substance to be dissolved by another? | solubility (7-2) |
What is the term for both the ability of a substance to carry heat and the ability of a substance to carry electricity? | Conductivity ("thermal" for heat; "electrical" for electricity") (7-2) |
What is the term for "mass per unit volume?" | density (7-2) |
What is the term for anything that has mass and takes up space? | matter (7-1) |
What small particle is called "the building block of matter?" | the atom (7-1) |
What is the center of an atom called? | nucleus (7-1) |
What are the parts of an atom, and what are their electric charges? | proton (positive), neutron (neutral), electron (negative) (7-1) |
Which two parts of the atom are found in the nucleus? | proton and neutron (7-1) |
What is a sample of matter that always has the same composition called? | a substance (7-1) |
What are the two kinds of substance? | elements and compounds (7-1) |
What are the two kinds of mixture? | homogeneous (evenly mixed); heterogeneous (not evenly mixed (7-1) |
What kind of mixture is a "solution?" | homogeneous (7-1) |