States of Matter
100: What are the three main states of matter?
Answer: Solid, liquid, gas.
100: What is a pure substance?
Answer: A material made of only one type of particle, with consistent properties.
100: What are characteristics of metals?
Answer: Metals are typically shiny, conductive, malleable, and ductile.
100: How is density calculated?
Answer: Density is calculated using the formula Density=Mass/Volume
100: Give an example of a physical change.
Answer: Melting ice or boiling water.
200: How does temperature affect states of matter?
Answer: Increasing temperature can change a solid to a liquid (melting) or a liquid to a gas (evaporation).
200: How can you separate a mixture?
Answer: Techniques include filtration, distillation, and chromatography.
200: Name a common nonmetal.
Answer: Oxygen or carbon.
200: What units are used to express density?
Answer: Common units include grams per cubic centimeter (g/cm³) and kilograms per cubic meter (kg/m³).
200: What is a chemical change?
Answer: A process where substances transform into different substances with new properties.
300: Describe what happens during a phase change.
Answer: A phase change involves a substance changing from one state of matter to another, often involving energy changes.
300: What is the difference between a homogeneous and heterogeneous mixture?
Answer: Homogeneous mixtures have uniform composition, while heterogeneous mixtures have visibly different components.
300: What is a metalloid? Give an example.
Answer: A metalloid has properties of both metals and nonmetals; an example is silicon.
300: How does temperature affect density?
Answer: Generally, as temperature increases, density decreases due to expansion.
300: How can you tell if a chemical change has occurred?
Answer: Indicators include color change, gas production, temperature change, or the formation of a precipitate.
400: What is plasma? Give an example.
Answer: Plasma is a state of matter where gases become ionized; examples include stars and fluorescent lights.
400: Give an example of a solution.
Answer: Saltwater or sugar dissolved in water.
400: How do metals typically react with acids?
Answer: Metals usually react with acids to produce hydrogen gas and a salt.
400: Explain buoyancy in terms of density.
Answer: An object will float if its density is less than the density of the fluid it is in.
400: Compare physical and chemical changes in terms of particle arrangement.
Answer: In physical changes, particle arrangement remains the same; in chemical changes, the arrangement of particles changes.
500: Explain the concept of sublimation.
Answer: Sublimation is the process where a solid changes directly to a gas without passing through the liquid state.
500: How does the boiling point differ between pure substances and mixtures?
Answer: Pure substances have a constant boiling point, while mixtures can boil over a range of temperatures.
500: Compare and contrast metals and nonmetals in conductivity.
Answer: Metals are good conductors of electricity and heat, while nonmetals are generally poor conductors.
500: What is the density of water, and why is it significant?
Answer: The density of water is approximately 1 g/cm³; it is significant as a reference point for measuring the density of other substances.
500: Describe how rusting of iron is a chemical change.
Answer: Rusting involves the reaction of iron with oxygen in the presence of water, forming a new substance (iron oxide) with different properties.