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Chemistry Final Exam Review 1. Define: a) mixture: _____________________________________________________________________ ______________________________________________________________________________ b) pure substance: _______________________________________________________________ ______________________________________________________________________________ 2. Beside each situation below list it as either a physical change or chemical change: 3. a) ice melts ________________________ b) wood burns _____________________________ c) a glass breaks ____________________ d) a snowflake forms _________________________ a) Define: heterogeneous: ___________________________________________________________ homogeneous: ____________________________________________________________ b) List the following as homogeneous or heterogeneous: i) pure sugar ______________________ ii) salt dissolved in water _________________________ iii) iron filings and sugar _______________________ iv) marbles and stones _______________________ 4. Define: a) chemical change ______________________________________________________________ ______________________________________________________________________________ b) physical change ______________________________________________________________ ______________________________________________________________________________ c) physical property ______________________________________________________________ ______________________________________________________________________________ d) chemical property ______________________________________________________________ ______________________________________________________________________________ 5. List each of the following as either a physical property or a chemical property: a) texture _____________________ b) odour __________________________ c) reaction with acid _____________________ d) clarity __________________________ 6. a) Define: qualitative observation _____________________________________________________ ________________________________________________________________________ quantitative observation _____________________________________________________ ________________________________________________________________________ b) List each observation below as qualitative or quantitative: i) the colour of the substance turned from orange to green _______________________________ ii) the mass of the substance decreased by 5.0 g ____________________________________ iii) a colourless liquid collected on the sides of the test tube ______________________________ iv) the liquid had a mass of 25.0 g _____________________________________ 7. a) Define: characteristic physical property ___________________________________________________ ______________________________________________________________________________ b) Check off the observations below that are characteristic physical properties: i) melting point _______ ii) boiling point ______ iii) density ______ iv) lustre _______ 8. Which of the following are considered to be pure substances and which are mixtures? a) elements _______________________ b) solutions ____________________________ c) compounds _______________________ 9. Define: a) element _____________________________________________________________________ ______________________________________________________________________________ b) compound ___________________________________________________________________ ______________________________________________________________________________ 10. Beside each of the following mark whether it is a physical change or a chemical change: a) moth balls sublimate into the air ______________________ b) iron rusts on a car _______________________ c) wood is chopped into little pieces _________________________ d) glass is shattered with a hammer __________________________ 11. a) List the 5 pieces of evidence of a chemical change: i. ____________________________________________ ii. ____________________________________________ iii. ____________________________________________ iv. ____________________________________________ v. ____________________________________________ b) Define precipitate: ____________________________________________________________________ _____________________________________________________________________________________ 12. State the gas tests for the following: a) oxygen: ____________________________________________________________________________ b) hydrogen: __________________________________________________________________________ c) carbon dioxide: ______________________________________________________________________ 13. List the 5 parts of the particle theory or matter: i. _____________________________________________________________________________ ii. _____________________________________________________________________________ iii. ____________________________________________________________________________ iv. ____________________________________________________________________________ v. _____________________________________________________________________________ 14. a) List the characteristics of metals: ________________________________________________________ b) List the characteristics of non-metals: _____________________________________________________ 15. Compare the reactivity of elements in families 1A, 2A, and 8A: _______________________________________ _____________________________________________________________________________________ 16. Complete the following table to compare subatomic particles: Particle Location Electric Charge Mass electron proton neutron 17. a) Define: ion __________________________________________________________________________ b) How does an atom become a: positive ion ___________________________________________ negative ion __________________________________________ 18. Define: atomic number: __________________________________________________________________ atomic mass: ___________________________________________________________________ 19. For a Bohr atom how many electrons can fit in each of the following shells? a) first ____________ b) second _____________ 20. Classify the diagrams below as elements, compounds, or mixtures 21. Add the following labels to the diagram of the periodic table below: c) third _______________ a) Groups 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A b) Alkali metals (AM), Alkaline Earth metals (AEM), Halogens (H), Noble gases (NG) c) Put "X"s through each of the elements in period 4 d) Draw the "staircase" e) Shade all the elements that are metals 22. Use the periodic table provided to answer the following questions: a) What is the chemical symbol for sodium? ___________________ b) What is the name for the element with chemical symbol Pb? _________________ c) What happens to the relative reactivity in the following set of elements? Na Mg ________________________ d) What happens to the relative reactivity in the following set of elements? K Na Li _______________________ 23. Complete the following table Element Symbol Nitrogen Atomic Number 5 17 24. Draw a Bohr Model for Fluorine 25. Complete the following table Atomic Mass Number of Protons Number of Neutrons Number of Electrons 5 35 17 Group Number of electrons in the outermost shell? 2A 5A 26. Write a word equation to describe the following reaction When iron burns in pure oxygen iron oxide is produced. 27. Determine the names and number of atoms of each element the following molecules (4) Molecule Atoms in the molecule Number of Molecule Atoms in the each atom molecule CaF2 2CO2 (NH4)2S Mg(ClO3)2 Number of each atom 28. Draw a set of Bohr diagrams to illustrate how oxygen and hydrogen share electrons to form H2O (water) Gold Nanoparticles Quickly Detect Hazardous Chemicals Gold nanoparticles align in a single layer in this graphical representation (Credit: Image courtesy of Imperial College London) ScienceDaily (Nov. 20, 2012) — Scientists at Imperial College London have developed a system to quickly detect trace amounts of chemicals like pollutants, explosives or illegal drugs. The new system can pick out a single target molecule from 10,000 trillion water molecules within milliseconds, by trapping it on a self-assembling single layer of gold nanoparticles. The team of scientists, all from the Department of Chemistry at Imperial, say this technology opens the way to develop devices that are compact, reusable and easy to assemble, and could have a range of uses including detecting illegal drugs, explosives, pollutants in rivers or nerve gases released into the air. Results of the research are published this week in Nature Materials. In one potential use, such a device could detect tiny traces of explosives or other illegal substances left behind by criminals on the surfaces they touch. The advances made by this team would help law enforcers to identify and deal with such activities involving illegal substances. Research co-author, Michael Cecchini, said: "Our system could solve a key problem of reliable and portable chemical testing for use in the outside world. It is very sensitive and could well be used to look for very small amounts of a specific molecule even in busy, public areas." The target molecules are identified by an effect called Surface Enhanced Raman Scattering (SERS) of light. This technique, which has been around since the late 1970's, works because each molecule scatters light in a unique way. Previous research has shown that the signal can be amplified by catching molecules in a particular way on a layer of metal nanoparticles. However, these sheets are complex to manufacture. The scientists overcame this problem by dealing with interfaces of two liquids that do not mix, such as water and oil, or water and air interface. By manipulating the electrical charge of the gold nanoparticles and the composition of the solution, they were able to create a situation where the particles line themselves up at the interface between the two non-mixable liquids, or between a liquid and the air. "The trick to achieving this system's sensitivity to the target molecules was in finding the conditions at which nanoparticles would settle at the interface at close distances to each other without fusing together," commented another co-author Jack Paget. If the nanoparticles are disturbed, they spontaneously arrange themselves back in the correct way make the device more robust than those made rigidly arranged particles. Research co-author, Vladimir Turek, said: "The system shows real promise for detectors for use in rough outdoor environmental and defence applications, since the liquids and nanoparticles can be easily replaced to regenerate the device." This research is supported by funds from the UK's Defence Science and Technology Laboratory (DSTL) and the European Research Council (ERC) starting investigator grant. The cross-disciplinary team in the Department of Chemistry at Imperial is led by Dr Joshua Edel, an expert in applied nanoscience, and Professor Alexei Kornyshev, professor of chemical physics and expert in condensed matter. They are corresponding authors of the study, alongside research postgraduates Michael Cecchini, Vladimir Turek and Jack Paget. 29. Use the article above to answer the following questions: a) List three things the nano particle layer can be used to detect: i. __________________________________ ii. __________________________________ iii. __________________________________ c) What is the name of the effect by which target molecules are identified? ____________________________________________________________________ b) When was this technique first developed? ______________________