Test One Review

1. Test One Review Chapters 2 and 3

2. Chemistry is the study of: • The composition, structure and properties of matter and the changes it undergoes.

3. Mass is a measure of… • The amount of matter in an object. • Matter is… • Anything that has mass and takes up space.

4. Volume is… • The space filled by matter. • Volume can be calculated by…? • L x W x H = V (cm3 ) • Volume of a liquid is measured in the lab using a…?

5. Density? • Amount of matter per unit space. • How tightly packed the matter is in an object. • Water has a density of 1g/ml… how do you think the density of cork compares to this? • Iron?

6. An atom is… • The smallest part of an element that maintains the properties of that element. • An element is… • A pure substance made up of only one kind of atom.

7. A compound is… • A pure substance made up of two or more elements that are chemically bonded.

8. Classify the following as element, compound or mixture: • Hydrogen gas • O2 • Water • Salt • Iron • N2

9. A physical property is… • a characteristic that can be observed or measured without changing the identity of the substance. • Often relate to physical changes.

10. Which of the following are physical properties. • Density • Melting point / Freezing point • Boiling point • Color • Crystal shape • Hardness • Luster • Malleability/ ductility

11. A physical change is a… • a change in a substance that does not involve a change in the identity of the substance.

12. Chemical property… • Relates to a substances ability to undergo chemical changes. • Can not be observed with out changing the identity of the matter. • Chemical change takes place when the identity and composition of a substance is altered…

13. Evidence that indicates a chemical change has taken place? • Flame, heat or light produced • Gas produced • Precipitate/color change • Give some examples of chemical changes…

14. What kind of change? Why?

15. Sodium bicarbonate was added to HCl. Describe the changes that took place. What likely happened to the mass of the flask containing the HCl and Sodium bicarbonate? What happened to the overall mass of products and reactants? What is a preciptate?

17. Classify the following as chemical property physical property: • The density of gold is 19.33 g/cm3 • Gold does not react with many chemicals but is attacked by chlorine and fluorine. • Hydrogen reacts with oxygen. • Gold is very malleable. • Gold has a melting point of 1337.33 K • Wax melts at 70 C • Paraffin reacts with oxygen • Iron rusts

18. A mixture…? • Is a blend of two or more substances each of which retains its own composition and properties. • May be separated into its components by physical means (evaporation, filtration, distillation)

19. Heterogeneous vs. Homogenous • Homogeneous have uniform composition (ex. solutions). You can not “see” the individual components in the mixture. • Heterogeneous do not have uniform composition.

20. Classify the following as heterogeneous or homogeneous: • AIR • Salt dissolved in water • Blood • Granite • Beach sand

21. Element, compound, heterogeneous or homogeneous mixture • Copper II chloride • Nitrogen gas • Gatorade • Salad dressing (italian) • Steel • iron

22. SI BASE UNITS • LENGTH … • METER • MASS … • KILOGRAM • TIME… • SECOND • TEMPERATURE … • KELVIN • AMOUNT OF SUBSTANCE… • MOLE

23. Each SI base unit has a defined standard… • Example 1 meter = the distance traveled by light in about 3.3 x 10-9 seconds. • Why?

24. Derived SI units • Volume… • V = L x W x H = m x m m = m3 • Density … • D = M/V = g/cm3 • Units derived from base units.

25. Conversion factor • A ratio between two quantities… • 1 dollar = 4 quarters… • $ 1 : 4 quarters. • Allow you to convert between units.

26. Make the following conversions using conversion factors. • 100 yards = _____ meters • 15 seconds = ____ days • 21 grams = _____ ounces • 12 ounces = _____ kilograms

27. Accuracy vs. Precision • Accuracy refers to… • The closeness of a measurements to the correct or accepted value… • Precision refers to… • The closeness of a set of measurements of the same quantity made in the same way.

28. How many significant figures in ? • 100.010 g • 0.002020 m • 6.02 x 10 23 atoms • 200 • 200.

29. Rounding calculations • Multiplication or division, round to the least number of significant figures in the measurements… • Addition or subtraction, round to the least number of places right of the decimal…

30. Calculate & round, don’t be a • 4.024cm x 1.1cm = • 3.002 g / 2 cm3 = • 4.0 g + 2.025 g =

31. Write the following in scientific notation • 200 m • 0.00204 g • 0.00004 cm • 300000000 m/s (the speed of light)

32. Solve the following problems: • The distance from Earth to the Sun is 1.5 x 108 km. How many feet is this • 3.5 x 107 gallons of water pass over Niagara falls each minute. How many milliliters is this?

33. If the density of aluminum is 2.7 g/cm3 what is the volume of a 0.50 gram piece of aluminum foil? 32.066 grams of sulfur contains 6.02 x1023 atoms. How many atoms are in a 9.05 gram sample of sulfur?

34. Things to remember when problem solving • Use conversion factors! • It is all about the units…so be sure to label. • Show all work clearly. • Round results appropriately. • UNITS, UNITS, UNITS.

35. UNITS, UNITS, UNITS • Use dimensional analysis. • No work, no units, no credit.

36. See also… • Unit one review outline and chapters 2 & 3 in text.