1 / 63

Introduction to Matter and Qualitative Analysis

Introduction to Matter and Qualitative Analysis. Welcome. While we are waiting for everyone to arrive, attempt the following problems before we begin Page 2  Questions 1 through 15. Particle Theory - Review. All Matter is made up of extremely tiny particles

alexia
Télécharger la présentation

Introduction to Matter and Qualitative Analysis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction to Matter and Qualitative Analysis

  2. Welcome • While we are waiting for everyone to arrive, attempt the following problems before we begin • Page 2  Questions 1 through 15

  3. Particle Theory - Review • All Matter is made up of extremely tiny particles • Each Pure substance has its own kind of particles, different from the particles of other pure substances • Particles are always moving -Particles at a higher temperature are generally moving faster, on average than particles at a lower temperature. • Particles attract each other

  4. What is matter? • Anything that has: • Mass • Volume • So pretty much everything.

  5. Physical Properties • Physical Properties- The characteristics of a substance. • There are three states of matter, what are they? • Solid • Liquid • Gas • All three of these states are physical states of matter.

  6. Physical Properties of Solids, Liquids and Gases

  7. Physical Properties • Physical property observations can be made using several senses. • Sight • Smell • Touch • Taste • Sound – This can only give additional information about the others

  8. Physical Properties

  9. Typical physical properties • Hardness- The measure of the resistance of a solid to being scratched or dented. A harder Material will dent a softer one. • Rank the following from hardest to softest. Steel nails, chalk, glass, diamond. • Diamond ˃ Steel nails ˃ Glass ˃ Chalk • Malleability- The ability to be hammered or bent into different shapes • Example Aluminum foil. • Brittle – Shatters easily

  10. Typical physical properties • Ductility- Can be pulled into a wire. • Example: Copper wires • Melting and Boiling Points - The temperatures at which substances change states. • Ex Water: MP = 0ºC , BP = 100 ºC

  11. Typical physical properties • Crystal Form – The solid forms of minerals • Example – Sodium chloride = table salt • Solubility- The ability a substance to dissolve in a solvent. • Eample: salt is soluble in water where pepper is not.

  12. Typical physical properties • Viscosity- Refers to how easily a liquid flows: the thicker the liquid the more viscous it is. • Density – The amount of mass per unit volume of that matter. (kg / cm3)

  13. Chemical properties (3) • A chemical property describes the behaviour of a substance as it becomes a new substance

  14. Chemical Properties 1. Combustibility is the ability of a substance to burn. In order to burn a substance requires Oxygen

  15. Chemical Properties • Light sensitivity is a chemical property of that can cause new substances to form when light hits it.

  16. Chemical Properties 3. Reacting with an acid is a chemical property where when acid is poured on a substance it produces a gas and bubbles.

  17. Classification Of Matter

  18. Pure Substance • A substance with constant composition. Can be classified an either an element or as a compound. • Examples: Table salt (sodium chloride, NaCl), sugar (sucrose, C12H22O11), water (H2O), iron (Fe), copper (Cu), and oxygen (O2).

  19. Element • A substance that cannot be separated into two or more substances by ordinary chemical (or physical) means. We use the term ordinary chemical means to exclude nuclear reactions. Elements are composed of only one kind of atom. • Examples: Iron (Fe), copper (Cu), and oxygen (O2).

  20. Compound • A substance that contains two or more elements, in definite proportion by weight. The composition of a pure compound will be invariant, regardless of the method of preparation. Compounds are composed of more than one kind of atom. • The term molecule is often used for the smallest unit of a compound that still retains all of the properties of the compound. • Examples: Table salt (sodium chloride, NaCl), sugar (sucrose, C12H22O11), and water (H2O).

  21. Mixture • Two or more substances, combined in varying proportions - each retaining its own specific properties. The components of a mixture can be separated by physical means, i.e. without the making and breaking of chemical bonds. • Examples: Air, table salt thoroughly dissolved in water, milk, wood, and concrete.

  22. Homogeneous Mixture • Mixture in which the properties and composition are uniform throughout the sample. Such mixtures are termed solutions.Examples: Air and table salt thoroughly dissolved in water

  23. Heterogeneous Mixture • Mixture in which the properties and composition are not uniform throughout the sample.Examples: Sand, Salads, chocolate chip cookies • - You will be able to see different substances in the mixture.

  24. Suspension • A cloudy mixture in which tiny particles of one substance are held within another. • Can be separated out when the mixture is poured through filter paper. • A suspension is also a heterogeneous mixture.

  25. Physical changes • In a physical change, the substance involved remains the same. The substance may change form or state, however. All changes of state are physical changes. • There are other physical changes that are not changes of state. Dissolving is a physical change. When sugar is dissolved it spreads out in the water but the sugar is still sugar. If the water was boiled off there would be sugar left over. Most Physical changes can be reversed.

  26. Chemical changes • In a chemical Change the substance is changed into one or more different substances. The new substances have different properties from the original substance. Most chemical changes are difficult to reverse and most cannot be. The new substances are not likely to combine and form the original substance. • Often during a chemical change you cannot see the change that has occurred in the substance, but you can observe the results of the change. There are clues that suggest that a chemical change has taken place.

  27. Building Scientific Knowledge

  28. Clues that a chemical change has occurred

  29. Clues that a chemical change has occurred

  30. Clues that a chemical change has occurred

  31. Clues that a chemical change has occurred

  32. Clues that a chemical change has occurred

  33. Qualitative Analysis • Qualitative analysis: Involves determining the composition of an unknown compound or mixture. This is usually done by investigating its physical and chemical properties.

  34. Quantitative Analysis • Refers to analyses in which the amount or concentration may be determined (estimated) and expressed as a numerical value in appropriate units. • Qualitative Analysis may take place without Quantitative Analysis, but Quantitative Analysis requires the identification (qualification) of the analyte for which numerical estimates are given.

  35. Observation and Inference • Observation: • A statement that is based on what you see, hear, taste, touch and smell. • Inference: • A judgement or opinion that is based on observations and/or conclusions

  36. In chemistry we use these two components of qualitative analysis frequently. • When trying to identify a sample of matter we • Observe the sample, and then • Infer what it is based on what we know about other matter.

  37. Empirical Knowledge and Theoretical Knowledge • Empirical Knowledge: • Knowledge coming directly from observations • It describes what is being observed • Theoretical Knowledge: • Knowledge based on ideas that are created to explain observations • We explain things by using theories that we know.

  38. Theory: • A explanation of a large number of related observations • Ex. Theory of relativity , Theory of evolution   • Model: • A model is a way of representing a theory or idea. • A model can change over time • Ex. The model of the atom , a globe of the earth.

  39. How to light a Bunsen burner • Step 1 • The first step is to check for safety - lab coat on, long hair tied back, safety glasses on, books and papers away from the flame, apparatus set up not too close to the edge of the table...

  40. How to light a Bunsen burner Step 2 • The second step is to look at the holes.  Check that the holes are closed.  The holes can be adjusted to let in more or less air by turning the collar(see photos below). Open Closed

  41. How to light a Bunsen burner • Step 3 • Hold the sparker in one hand above the burner and turn on the gas with the other. • As soon as you turn the gas on start sparking. • NOTE: some have an extra gas valve to them. Look before you light it.

  42. How to light a Bunsen burner • Step 4 • Adjust the flame by turning the collar so that you have the appropriate flame for the experiment (usually the medium blue flame). 

  43. How to light a Bunsen burner • Step 5 • During the experiment, stay vigilant so that if a problem occurs, you are ready to turn off the flame quickly.  This means that you should not leave your bench unattended. 

  44. Now its your turn • Everyone in the class must show that the know how to do this properly before they can continue with the activity.

  45. Homework “The Burning Candle” lab on page 11 Do this now Class / Homework – page 12 # 1- 6 Do this later

  46. Questions • Classify each of the following statements as either an inference or an observation • The wood does not burn because it is wet • The boiling point of methanol is 67.5 C • The light that a glow stick emits can be prolonged if the glow stick is placed in a fridge • The temperature of a metal increased due to an increase in the vibrations of the atoms within it. • There is 125mL of water in the flask

  47. 2. “Theories cannot be prove; they can only be supported with experiment evidence” Comment on this statement 3. Explain how models are useful for conveying a theory or idea 4. Using a concept map, illustrate how the following terms are interconnected: empirical knowledge, inference, observation, theory.

  48. 5. In a court of law, responses from witnesses who state opinions are often stuck from the record. Give reasons why a lawyer may want a witness to make statements based on observations rather than inferences. 6. Qualitative chemical analysis involves identifying a substance through diagnostic tests. Diagnostic test are based on physical and chemical properties of substances. Is qualitative analysis empirical or Theoretical. Give reasons.

  49. The periodic Table

  50. The Foundation of the periodic Table • Dmitri Mendeleev devised and published the periodic table in in 1869. • Mendeleev found he could arrange the 65 elements that were then known in a grid or table so that each element had: • 1. A higher atomic weight than the one on its left. • 2. Similar chemical properties to other elements in the same column. • He did not know about orbits at this time

More Related