Chemistry Quiz

1. Chemistry Quiz Answer Key

2. 1. Which is true of a mechanical mixture? • Made up of more than one substance, and the substances are clearly distinguishable from each other. • Made up of more than one kind of substance, and the substances are not distinguishable from each other. • It is made up of two or more metals. • It is made up of only one type of substance.

3. 5.1 The Classification of Matter • Mechanical Mixture – can visually distinguish the different substances.

4. 1. Which is true of a mechanical mixture? • Made up of more than one substance, and the substances are clearly distinguishable from each other. • Made up of more than one kind of substance, and the substances are not distinguishable from each other. • It is made up of two or more metals. • It is made up of only one type of substance.

5. 2. Which of the following is NOT a characteristic physical property? • density • melting point • boiling point • volume

6. 5.6 Characteristic Physical Properties • Characteristic Physical properties are physical properties unique to a substance and thus can be used to identify the substance • Example: Density is the amount of matter per unit volume of that matter. (Mass/volume) characteristic physical properties freezing point melting point density Less Dense More Dense

7. 5.6 Characteristic Physical Properties There are other characteristic physical properties that can be used to identify unknown substances: characteristic physical properties freezing point melting point density Melting point Boiling point Freezing point

8. 2. Which of the following is NOT a characteristic physical property? • density • melting point • boiling point • volume

9. 3. Which is a chemical change? • liquid candle wax solidifying • paper being folded • iron rusting • clay being torn into smaller pieces

10. 5.3 Chemical Properties and Chemical Changes • These are some examples of possible chemical change: • Change of colour. • Change of odour. • Gas bubbles • New solids being formed. (precipitate). • Heat or light being released. • Chemical changesinvolve the formation of one or more new substances. chemical property precipitate chemical change

11. Physical CHANGE or Chemical CHANGE? Change of state is a physical change

12. 3. Which is a chemical change? • liquid candle wax solidifying • paper being folded • iron rusting • clay being torn into smaller pieces

13. 4. The atomic mass of an element is based on: • the number of electrons and the number of neutrons of that element • the number of protons and the number of neutrons of that element • the number of protons and the number of electrons of that element • none of the above

14. Atom is made up of subatomic particles Particle Symbol Charge Relative Location Mass Proton p+ 1+ 1 Nucleus Neutron n 0 1 Nucleus Electron e- 1- 0 Orbit around nucleus

15. 4. The atomic mass of an element is based on: • the number of electrons and the number of neutrons of that element • the number of protons and the number of neutrons of that element • the number of protons and the number of electrons of that element • none of the above

16. 5. Group 1 of the periodic table consists of very reactive metal elements. The special name for this group is: • halogens • alkali metals • alkaline earth metals • noble gases

17. Group 1: Alkali Metals Shiny, silvery and soft Relatively low densities, can float on water Highly reactive (combine readily with other elements and compounds) Become more reactive as you move down the periodic table

18. 5. Group 1 of the periodic table consists of very reactive metal elements. The special name for this group is: • halogens • alkali metals • alkaline earth metals • noble gases

19. Elements on Group 17 of the periodic table share the following similarity: • they all have 1 electron on the very outer shell • they all have 5 electrons on the very outer shell • they all have 3 electrons on the very outer shell • they all have 7 electrons on the very outer shell

20. Trends of Periodic Table Group 17 Electrons arrangement on orbitals Group 17 Outer Shell has 7 electrons Group name: Halogens 9 F = 2 + 7 17 Cl = 2 + 8 + 7

21. Elements on Group 17 of the periodic table share the following similarity: • they all have 1 electron on the very outer shell • they all have 5 electrons on the very outer shell • they all have 3 electrons on the very outer shell • they all have 7 electrons on the very outer shell

22. 7. Which of the following is NOT TRUE for neutrons: • neutron has a relative mass of 1 • neutron was first discovered by Chadwick • neutron orbits around the nucleus • neutron has no charge

23. Atom is made up of subatomic particles Particle Symbol Charge Relative Location Mass Proton p+ 1+ 1 Nucleus Neutron n 0 1 Nucleus Electron e- 1- 0 Orbit around nucleus

24. 7. Which of the following is NOT TRUE for neutrons: • neutron has a relative mass of 1 • neutron was first discovered by Chadwick • neutron orbits around the nucleus • neutron has no charge

25. 6 C = 2 + 4 8. Which atom has two electrons in its outer orbit? • carbon • oxygen • neon • beryllium 8 O = 2 + 6 10 Ne = 2 + 8 4 Be = 2 + 2

26. 9. What is the name given to the number of protons in an atom? • atomic mass • atomic number • isotope • period

27. Atomic Number Counts the number of PROTONS in an atom Atomic Number Symbol Q: How many protons does a sodium have? 11 Na

28. 9. What is the name given to the number of protons in an atom? • atomic mass • atomic number • isotope • period

29. 10. Which of the following statements is true regarding the number of protons and electrons in an atom? • There are more protons than electrons. • There are more electrons than protons. • The number of protons equals the number of electrons. • The relationship between the number of protons and the number of electrons varies by atom.

30. Number of Electrons An atom is neutral, meaning its net charge is zero. To get this neutrality, Number of protons = Number of electrons Therefore, for any atom: Atomic number = Number of protons = Number of electrons

31. 10. Which of the following statements is true regarding the number of protons and electrons in an atom? • There are more protons than electrons. • There are more electrons than protons. • The number of protons EQUALS the number of electrons. • The relationship between the number of protons and the number of electrons varies by atom.

32. 11. The atomic mass of argon is 39.948 u. Therefore, the most common isotope of argon would most likely have how many neutrons in its atoms? • a. 18 b. 40 c. 22 d. 39

33. Mass Number We can use the mass number to find the number of neutrons: 1. Round the mass to nearest whole number 2. Subtract the number of protons from it 18 protons 18 electrons 22 neutrons - 18 = 18 Ar 40

34. 11. The atomic mass of argon is 39.948 u. Therefore, the most common isotope of argon would most likely have how many neutrons in its atoms? • a. 18 b. 40 c. 22 d. 39

35. 12. The diagram on the right shows a neutral atom. Which element would have atoms with similar chemical properties? • gallium • silicon • calcium • phosphorus 3 valence electrons Group 13!

36. 80-35 =45 79.9 35 35 Non-metals Br 31-15 =16 Phosphorus 31.0 15 15 Non-metals 64-29 =35 Cu 63.5 Copper 29 Metals Cl 36 – 17 =19 Non-metals 17 Chlorine 35.5

37. Use your knowledge of the Particle Theory of Matter to explain why the smell of a freshly baked bread will quickly fill a room Heat on dough  chemical reaction occurs • gas produced (odour/smell) • gas particles are in constant random motion • The particles of a substance move faster as its temperature increases • Thus the smell will diffuse quickly within the room

38. 14. During a family BBQ, Uncle Bob threw a red piece of steak on the hot grill. Describe any clues you would observe during that time that indicate a chemical change has taken place.

39. Colour change noticed on steak • Smoke/odour being produced • Texture of the steak changes

40. 15. Iron and potassium are both metals. Offer 2 reasons why potassium could not be used to make a cooking pan like an iron skillet.

41. Group 1: Alkali Metals Shiny, silvery and soft Relatively low densities, can float on water Highly reactive(combine readily with other elements and compounds) Become more reactive as you move down the periodic table

42. 16. With regards to the following Group 18 elements, • Draw Bohr-Rutherford diagram. Include protons, neutrons and electrons in your diagram: He (helium) and Ne (neon)

43. Drawing Bohr-Rutherford Diagram Helium (He) Atomic Number = 2 # protons = 2 2 p+ 2 n0 # electrons = 2 Atomic Mass = 4.00 # neutrons = 4 – 2 = 2

44. With regards to the following Group 18 elements, b. Identify some of the physical / chemical properties associated with Group 18 elements

45. Group 18: Noble Gases Stable nature / unreactive Colourless, odourless, and tasteless Glow brightly when an electrical current is passed through them Non-toxic (except for Radon)

46. With regards to the following Group 18 elements, c. Use your Bohr-Rutherford diagrams to explain why both He and Ne show similar properties and thus classified in the same chemical family 2 p+ 2 n0 10 p+ 10 n0

47. Patterns in the Periodic Table Similar properties seen in chemical families (or groups) are due to similarities in their electrons arrangement Both He and Ne have FULL outer orbit. Thus they both are unreactiveand included in the Noble gases family.

48. 17. Pick ONE of the scientists listed below. Briefly described their experiment and contribution to the development of the structure of an Atom. • Choices are: a) Ernest Rutherford b) J.J. Thomson c) Niels Bohr

49. Theories of the Atom 6.6 Ernest Rutherford (1909) • Experiment fired small, positively charged particles at a thin piece of gold foil,

50. Theories of the Atom 6.6 Ernest Rutherford (1909): The Nucleus and the Proton • Rutherford theorized that the centre (nucleus)of the atom consists of positively charge particles called protons. • The nucleus is surrounded by a cloud of negatively charged electrons, and the atom is mostly empty space.