iGCSE Chemistry Section 1 Lesson 1 State of Matter.ppt
- 2. Content The iGCSE Chemistry course Section 1 Principles of Chemistry Section 2 Chemistry of the Elements Section 3 Organic Chemistry Section 4 Physical Chemistry Section 5 Chemistry in Society
- 3. Content Section 1 Principles of Chemistry a) States of matter b) Atoms c) Atomic structure d) Relative formula mass e) Chemical formulae and chemical equations f) Ionic compounds g) Covalent substances h) Metallic crystals i) Electrolysis
- 4. Content Lesson 1 a) States of matter Understand that all matter is made of atoms Describe the three states of matter as solid, liquid and gas in terms of the arrangement, separation and motion of particles. Describe the changes in arrangement, movement and energy of particles during these interconversions.
- 6. What’s the difference? Solids Liquids Gases Shape Can you pour? Can you stir? Can you squash?
- 7. Solids Liquids Gases Shape Fixed Can be changed No shape Can you pour? No Yes Yes? Can you stir? No Yes Yes? Can you squash? No Yes? Yes What’s the difference?
- 13. Solid Liquid Gas Particles are fixed in place and cannot move Changes of State
- 14. Solid Liquid Gas Particles are fixed in place and cannot move Particles are free to move within a container Changes of State
- 15. Solid Liquid Gas Particles are fixed in place and cannot move Particles are free to move within a container Particles are free to move about Changes of State
- 16. State of Matter • By the end of the lesson –you will be able to explain what vacuum is. –you will be able to test, observe and classify some common gases.
- 17. State of Matter • What is vacuum? • What comes to mind when you hear vacuum.
- 19. State of Matter • What gas is that? • What steps are used to test for the gases?
- 25. • Classwork –Science textbook –page 60 Question 1, 2, 3
- 26. SOLIDS • Strong forces of attraction • held in fixed position • lattice arrangement • don’t move, so have definite shape and volume • vibrate
- 27. SOLIDS • as they become hotter, the particles vibrate more. • so they expand • can’t be compressed • generally very dense
- 28. SOLIDS • when heated, molecules gain energy. • they vibrate more and more • strong forces are overcome, molecules start to move = MELTED
- 29. LIQUIDS • Some attraction between molecules. • free to move • no definite shape, but take shape of container • molecules in constantly random motion
- 30. LIQUIDS • when heated, they move faster and expand • can’t be compressed • quite dense
- 31. LIQUIDS • heat makes the molecules move faster as they gain energy. • fast moving molecules at the surface will overcome forces of attraction and escape = EVAPORATION
- 32. GASES • no force of attraction • free to move, travel in straight lines • sometimes collide • no definite shape or volume, expand to fill space
- 33. GASES • exert pressure on wall of container • constantly moving randomly • move faster when heated • can be compressed • very low densities
- 34. GASES • when heated enough, molecules have enough speed and energy to overcome forces and escape each other. • molecules break away in big bubbles of gas = BOILING
- 37. Content Lesson 1 a) States of matter b) Atoms c) Atomic structure 1.4 describe simple experiments leading to the idea of the small size of particles and their movement including: i dilution of coloured solutions ii diffusion experiments 1.5 understand the terms atom and molecule 1.6 understand the differences between elements, compounds and mixtures 1.7 describe techniques for the separation of mixtures, including simple distillation, fractional distillation, filtration, crystallisation and paper chromatography.
- 38. Evidence of particles Particles are very, very small, but what evidence do we have that they actually exist? Two simple experiments help us to prove their existence: 1. Dilution of coloured solutions 2. Diffusion experiments
- 39. Dilution of coloured solutions Blue copper sulphate crystal
- 40. Dilution of coloured solutions Blue copper sulphate solution
- 41. Dilution of coloured solutions Dilution, 10cm3 copper sulphate solution + 90cm3 water
- 42. Dilution of coloured solutions Dilution, 10cm3 copper sulphate solution + 90cm3 water
- 43. Dilution of coloured solutions Dilution, 10cm3 copper sulphate solution + 90cm3 water
- 44. Dilution of coloured solutions Serial dilution of a solution such as copper sulphate provides evidence that the original crystal was made up of many small particles that spread out evenly when the solution is diluted by adding water.
- 45. Evidence of particles – diffusion experiments Spray air freshener in the corner of a room
- 46. Evidence of particles – diffusion experiments Particles spread out in all directions
- 47. Evidence of particles – diffusion experiments Eventually the particles occupy the whole room
- 48. Evidence of particles – diffusion experiments Other examples of diffusion include: Smell of frying bacon from a kitchen Leaking of air from inside a balloon Sugar dissolving in a cup of tea
- 49. Evidence of particles – diffusion experiments Diffusion is the movement of particles from areas of high concentration to areas of low concentration until they are evenly spread. Diffusion depends upon the random movement of particles.
- 50. Evidence of particles – diffusion experiments Diffusion is the movement of particles from areas of high concentration to areas of low concentration until they are evenly spread. Diffusion depends upon the random movement of particles. Diffusion is slower in liquids than in gases because liquid particles are not as free to move as gas particles.
- 51. Atoms and Molecules The basic building blocks of everything that we see in the Universe are atoms. The word ‘atom’ basically means ‘indivisible’.
- 52. Atoms and Molecules The basic building blocks of everything that we see in the Universe are atoms. The word ‘atom’ basically means ‘indivisible’. Combinations of atoms are called molecules. For example: O2 - a molecule of oxygen H2O - a molecule of water
- 53. Elements, mixtures and compounds
- 54. Elements, mixtures and compounds Cu Cu Cu Cu Cu An element consists of one type of atom only. For example, pure copper consists of copper atoms only.
- 55. Elements, mixtures and compounds A mixture consists of different types of atoms that are not chemically bonded. Fe Fe Fe S S S S
- 56. Elements, mixtures and compounds A mixture consists of different types of atoms that are not chemically bonded. Fe Fe Fe S S S S 1. Particles in a mixture can all be separated out quite easily. 2. No chemical bonds exist 3. Properties of the mixture are just a mixture of the properties of the separate parts.
- 57. Elements, mixtures and compounds Fe Fe S S C O O In a compound the particles are held together by strong forces called chemical bonds. A chemical reaction will have taken place.
- 58. Elements, mixtures and compounds Fe Fe S S C O O In a compound the particles are held together by strong forces called chemical bonds. A chemical reaction will have taken place. 1. Particles in a compound are very difficult to separate. 2. The properties of a compound are very different to the properties of the original elements.
- 59. You need to be able to describe techniques for separating mixtures.
- 60. You need to be able to describe techniques for separating mixtures. Filtration Simple distillation Fractional distillation Crystallisation Paper chromatography
- 61. Filtration Filtration depends upon the different size of particles in a mixture. The filtrate passes through the filter paper, the residue is left behind. The technique is used to separate an insoluble solid from a liquid, eg. sand and water.
- 62. Simple distillation Simple distillation depends upon the different boiling points in a mixture. The lowest boiling point evaporates first and can be collected The technique is used to separate a soluble solid and a liquid, eg. pure water from salty water.
- 63. Fractional distillation Fractional distillation is used to separate two liquids that have different boiling points. The technique is used to separate mixtures such as ethanol and water
- 64. Crystallisation Crystallisation is used to separate a soluble solid from a liquid when you want to collect the solid. The technique is used to separate mixtures such as salt and water when the salt is required.
- 65. Paper chromatography Chromatography is used to separate and identify mixtures that are, or can be, coloured. The technique is used to separate mixtures such as the pigments in an ink sample.
- 66. Content Lesson 1 a) States of matter b) Atoms c) Atomic structure 1.8 recall that atoms consist of a central nucleus, composed of protons and neutrons, surrounded by electrons, orbiting in shells 1.9 recall the relative mass and relative charge of a proton, neutron and electron 1.10 understand the terms atomic number, mass number, isotopes and relative atomic mass (Ar) 1.11 calculate the relative atomic mass of an element from the relative abundances of its isotopes 1.12 understand that the Periodic Table is an arrangement of elements in order of atomic number 1.13 deduce the electronic configurations of the first 20 elements from their positions in the Periodic Table 1.14 deduce the number of outer electrons in a main group element from its position in the Periodic Table.
- 67. The size of an atom This is the head of a pin. Millions of atoms would fit onto it.
- 68. A spoonful of sugar A spoonful of sugar would contain about: 602,000,000,000,000,000,000,000 atoms!
- 69. So, atoms are very, very, small!
- 70. An atom is the smallest particle of an element that can exist. Cut a diamond up with a “magic knife” until you have the smallest piece possible, and you have a …. CARBON ATOM
- 71. This is a block of GOLD Being an ELEMENT, it is a PURE substance, so it contains particles of only ONE kind … GOLD ATOMS
- 72. THE ATOM
- 74. THE ATOM THE NUCLEUS • middle of the atom • contains protons and neutrons • positive charge (protons are positive) • almost all atom mass is concentrated in the nucleus • tiny compared to the atom as a whole
- 76. THE ATOM THE ELECTRONS • move around the nucleus • Negatively charged • tiny, but cover a lot of space • orbit volume determines size of the atom • virtually no mass • occupy orbits or shells around the nucleus
- 78. FACTS ABOUT THE ATOM! 1. NEUTRAL ATOMS HAVE NO CHARGE OVERALL 2. CHARGE ON THE ELECTRONS IS THE SAME SIZE AS THE CHARGE ON THE PROTONS BUT OPPOSITE 3. IN A NEUTRAL ATOM THE NUMBER OF ELECTRONS EQUALS THE NUMBER OF PROTONS 4. ELECTRONS MAY BE LOST OR GAINED. THE ATOM THEN BECOMES CHARGED, AND IS KNOWN AS AN ION 5. NEUTRON NUMBERS ARE USUALLY JUST A BIT HIGHER THAN PROTON NUMBERS, BUT CAN CHANGE
- 79. FACTS ABOUT THE ATOM! Particle Mass Charge Proton 1 +1 Neutron 1 0 Electron 1/2000 -1
- 80. Atomic Mass and Mass Number
- 81. Atomic Mass and Mass Number Na 23 11 Symbol for sodium
- 82. Atomic Mass and Mass Number Na 23 11 MASS NUMBER = total number of protons and neutrons
- 83. Atomic Mass and Mass Number Na 23 11 MASS NUMBER = total number of protons and neutrons ATOMIC NUMBER = number of protons (also electrons)
- 84. Atomic Mass and Mass Number Na 23 11 MASS NUMBER = total number of protons and neutrons ATOMIC NUMBER = number of protons (also electrons) Number of neutrons = mass number – atomic number
- 85. Atomic Number and Mass Number Na 23 11 MASS NUMBER = total number of protons and neutrons ATOMIC NUMBER = number of protons (also electrons) Mass number is always bigger than the atomic number
- 86. Atomic Mass and Mass Number Na 23 11 MASS NUMBER = total number of protons and neutrons ATOMIC NUMBER = number of protons (also electrons) For sodium: protons = 11, electrons = 11, neutrons = 12
- 87. What is an isotope?
- 88. What is an isotope? ISOTOPES ARE: different atomic forms of the same element, having the same number of PROTONS but different numbers of NEUTRONS
- 89. What is an isotope? ISOTOPES ARE: different atomic forms of the same element, having the same number of PROTONS but different numbers of NEUTRONS FOR EXAMPLE, there are two common forms of carbon: C 12 6 Carbon 12 Protons = 6 Neutrons = 6 Electrons = 6
- 90. What is an isotope? ISOTOPES ARE: different atomic forms of the same element, having the same number of PROTONS but different numbers of NEUTRONS FOR EXAMPLE, there are two common forms of carbon: C 12 6 Carbon 12 Protons = 6 Neutrons = 6 Electrons = 6 C 14 6 Carbon 14 Protons = 6 Neutrons = 8 Electrons = 6
- 91. What is an isotope? ISOTOPES ARE: different atomic forms of the same element, having the same number of PROTONS but different numbers of NEUTRONS FOR EXAMPLE, there are two common forms of carbon: C 12 6 Carbon 12 Protons = 6 Neutrons = 6 Electrons = 6 C 14 6 Carbon 14 Protons = 6 Neutrons = 8 Electrons = 6 Chemical properties are the same because the different number of neutrons in the nucleus doesn’t affect the chemical behaviour at all.
- 92. What is RELATIVE ATOMIC MASS? By definition: “mass of a particular atom compared to the mass of an atom of hydrogen”
- 93. What is RELATIVE ATOMIC MASS? By definition: “mass of a particular atom compared to the mass of an atom of hydrogen” Relative atomic mass is also the same as the mass number – it’s that simple!
- 94. What is RELATIVE ATOMIC MASS? By definition: “mass of a particular atom compared to the mass of an atom of hydrogen” Relative atomic mass is also the same as the mass number – it’s that simple! So why do some atoms have odd-looking relative atomic masses? Eg: Cl 35.5 17
- 95. What is RELATIVE ATOMIC MASS? By definition: “mass of a particular atom compared to the mass of an atom of hydrogen” Relative atomic mass is also the same as the mass number – it’s that simple! So why do some atoms have odd-looking relative atomic masses? Eg: Cl 35.5 17 Why has chlorine got a relative atomic mass (or mass number) of 35.5?
- 96. What is RELATIVE ATOMIC MASS? It’s because chlorine has two common isotopes (remember those?) Cl 35 17 Cl 37 17 AND
- 97. What is RELATIVE ATOMIC MASS? It’s because chlorine has two common isotopes (remember those?) Cl 35 17 Cl 37 17 AND They are found naturally in the ratio 3:1
- 98. What is RELATIVE ATOMIC MASS? It’s because chlorine has two common isotopes (remember those?) Cl 35 17 Cl 37 17 AND They are found naturally in the ratio 3:1 So the average relative atomic mass = 35 + 35 + 35 + 37 = 35.5 4
- 99. What is RELATIVE ATOMIC MASS? It’s because chlorine has two common isotopes (remember those?) Cl 35 17 Cl 37 17 AND They are found naturally in the ratio 3:1 So the average relative atomic mass = 35 + 35 + 35 + 37 = 35.5 4 So chlorine is written as: Cl 35.5 17
- 100. Where do we find the relative atomic mass and atomic number of an element, and so calculate the number of protons, neutrons and electrons in an atom?
- 101. Where do we find the relative atomic mass and atomic number of an element, and so calculate the number of protons, neutrons and electrons in an atom? We look in the Periodic Table!
- 103. Vertical columns are called GROUPS, and numbered from 1 to 8
- 104. 1 2 3 4 5 6 7 8
- 105. Horizontal rows are called PERIODS, and numbered from 1 to 7
- 106. 1 2 3 4 5 6 7
- 107. So for any given element we can read off the group and period number.
- 108. So for any given element we can read off the group and period number. For example: Silicon (Si) is Group 4 and Period 3
- 109. So for any given element we can read off the group and period number. For example: Silicon (Si) is Group 4 and Period 3 Also, for any given element we can record the Atomic Number and Relative Atomic Mass
- 110. Atomic number (4) Relative Atomic Mass (9)
- 111. Let’s just pause and recap a second ………
- 112. Let’s just pause and recap a second ……… You should now know how to find out for any given element: The Relative Atomic Mass (Mass number) The Atomic Number The Number of Protons The Number of Neutrons The Number of Electrons Are you ready for some practice?
- 113. Element Symbol Atomic number Relative atomic mass Number of protons Number of neutrons Number of electrons Hydrogen 1 1 Li 7 4 Potassium 19 20 Beryllium 5 4 Ca 20 20 Iron 56 30 Boron 6 5 Ne 10 10
- 114. Element Symbol Atomic number Relative atomic mass Number of protons Number of neutrons Number of electrons Hydrogen H 1 1 1 0 1 Lithium Li 3 7 3 4 3 Potassium K 19 39 19 20 19 Beryllium Be 4 9 4 5 4 Calcium Ca 20 40 20 20 20 Iron Fe 26 56 26 30 26 Boron B 5 11 5 6 5 Neon Ne 10 20 10 10 10
- 115. Note: the Periodic Table is arranged in order of increasing atomic number, not mass number.
- 116. Do you remember that electrons are found in orbits (or shells) around the nucleus?
- 117. Do you remember that electrons are found in orbits (or shells) around the nucleus? The orbits can only hold a certain number of electrons:
- 118. Do you remember that electrons are found in orbits (or shells) around the nucleus? The orbits can only hold a certain number of electrons: The first orbit can hold up to 2 electrons The second orbit can hold up to 8 electrons The third orbit can hold up to 8 electrons Let’s look at some examples:
- 119. Lithium has an atomic number of 3 so has 3 electrons. The first 2 electrons go into the first orbit (shell) and the remaining electron goes into the second orbit.
- 120. Lithium has an atomic number of 3 so has 3 electrons. The first 2 electrons go into the first orbit (shell) and the remaining electron goes into the second orbit. The electron configuration (arrangement) can also be written in this format.
- 121. Silicon has an atomic number of 14 so has 14 electrons. The first 2 electrons go into the first orbit (shell), the next 8 go into the second orbit, and the remaining 4 electrons go into the third orbit. To make sure you understand this, try drawing the electron configurations for the first 20 elements (hydrogen to calcium)
- 122. The Periodic Table can also help us when we are trying to work out the electron configuration of a particular element.
- 123. The Group Number tells you how many electrons there are in the outer shell (orbit) of an element. For example, oxygen is in Group 6, so has 6 electrons in its outermost shell (2:6)
- 124. The Period Number tells you how many shells (orbits) there are around the nucleus. For example, Calcium is in Period 4, so will have 4 shells around the nucleus
- 125. The Period Number tells you how many shells (orbits) there are around the nucleus. For example, Calcium is in Period 4, so will have 4 shells around the nucleus
- 126. End of Lesson 1 In this lesson we have covered: States of Matter Atoms Atomic structure