Matter Review Physical Science

1. Define each of the following: Atom- The smallest unit of an element that keeps the properties of that element Element- a substance that cannot be broken down into simpler substances by chemical means Compound- a substance that is made up of atoms of different elements. When elements combine to form a compound, they always combine in the same proportion. Compounds are represented by chemical formulas. Mixture- made up of more than one type of substances. Chemical change- occurs when a new substance is formed Matter- anything that has mass and takes up space Pure substance- has a fixed composition 2. Because the substances found in a mixture are not chemically combined (bonded), they are easier to separate. Tell how each of the following methods could be used: Filtering – to separate a solid from a liquid (ex: sand and water) Magnetism – to separate magnetic substances from a mixture (ex: iron filings)

3. Many physical properties are useful because they can help to identify an unknown substance. Name 3 physical properties that can be used in this way. Color, shape, size, temperature, mass, boiling point 4. Identify each of the following as an element or a compound: Water- C gold- E oxygen- E Carbon- E sugar- C carbon dioxide- C Hydrogen- E salt- C iron-E

5. Tell whether each statement is describing a mixture or a compound: -forms a new substance- compound -alloy of steel- mixture -each part retains its own properties- mixture -can see different parts- mixture -composed of atoms from different elements that have chemically combined- compound -must be chemically separated- compound -could be separated by filtering- mixture -can be separated by physical means- mixture

6. Tell whether each statement is describing a homogeneous (solution) or a heterogeneous mixture: -could be separated by filtering- Heterogeneous -looks the same throughout- Homogeneous -formed by dissolving something- Homogeneous -can see the various components- Heterogeneous 7. Which of these is a chemical property? flammability, able to oxidize, color, melting point of 50 ̊ C, reacts with acid, mass, fading of paint, good heat conductor, dissolves in water, combustible, high viscosity Flammability, Oxidize, Reacts with Acid, Fading of Paint, Combustible

8. What is viscosity. A measure of the resistance to flow of a fluid 8. What is viscosity? A measure of the resistance to flow of a fluid. Which has the higher viscosity…syrup or water? Syrup because it has a greater resistance to flow than water. 9. Calculate the density of a gas that has a mass of 0.050 g and a volume of 6.4 mL. Use the formula D=m/v. 0.0078 g/mL 10. A substance has a mass of 500 g and a volume of 252 mL. What is the density? 1.98 g/mL

11. In order to float in water, a substance must have a density that is LESS than the density of water (which is 1.0 g/mL). Which of the following substances will float in water? Air = .001 g/cm3 Yes Corn oil = .93 g/cm3 Yes Glycerin = 1.26 g/cm3 No Corn syrup = 1.38 g/cm3 No Wood = .85 g/cm3 Yes Steel = 7.81 g/cm3 Definitely Not Rubber = 1.34 g/cm3 No Ice = .92 g/cm3 Yes

11. In order to float in water, a substance must have a density that is LESS than the density of water (which is 1.0 g/mL). Which of the following substances will float in water? -Air, Corn oil, Wood, Ice 12. Does each statement describe a solid, a liquid, or a gas? -has the most kinetic energy—gas -definite shate, definite volume—solid -has a definite volume, but no definite shape—liquid -move very little—solid -particles closest together—solid -will take shape of container, but has a stronger attractive force than gases—liquid -will hold its shape without a container—solid -made up of particles in motion—gas

13. What happens to the motion of the particles of a substance when the temperature increases? -motion increases 14. A substance melts from a solid to a liquid. Is this a physical or chemical process? Explain why. -physical because it is making a phase change 15. While a substance is changing phase, what happens to the temperature? -temperature doesn’t change (boiling point is always 100 degrees C or melting point is always 0 degrees C) 16. While a substance is changing phase, what happens to the amount of energy? -Energy is added as a phase change occurs

17. What is the name of each of the following phase changes? -solid to liquid—melting -liquid to gas—boiling -gas to liquid—condensation -liquid to solid—freezing -solid directly to gas—sublimation -liquid to gas (not at the boiling point)—evaporation 18. Use the graph to answer the following questions: What is the melting point of the substance? 20°C b. What is the boiling point of the substance? 50°C

c. How do you know if the temperature is increasing c. How do you know if the temperature is increasing? -the diagonal on the graph is increasing upward d. How do you know if the substance is changing phase? -a horizontal line, or slope of zero, indicates a phase change 19. A piece of wood that measures 3.0 cm by 6.0 cm by 4.0 cm has a mass of 80.0 g. What is the density of the wood? Would the piece of wood float in water? D=m/v D=80.0g/(3.0cm x 6.0cm x 4.0cm) D=80.0g/72cm^3 D=1.11 g/cm^3 It would NOT float in water because it is more dense than water.

20. OMIT 21. What is the volume of a tank that can hold 18754 kg of methanol whose density is 0.788 g/mL? D=m/v V=m/D V=18754000 g/ 0.788 g/mL V= 23799492 mL 22. What is the density of a board whose dimensions are 5.54 cm x 10.6 cm x 199 cm and whose mass is 28.6 kg? D=28600 g/ 11686.08 cm^3 D=2.45 g/cm^3