Chemistry at Home

13. Write word and balanced symbol equations for a range of reactions, including neutralisation reactions 14. Recall the reactions of acids with metals and carbonates, including writing word and balanced symbol equations for them

1. ACID + METAL HYDROXIDE (OR OXIDE) SALT + WATER (NEUTRALISATION) Example: HCl(aq) + NaOH(aq) NaCl(aq) + H2O(l) 2. ACID + ACTIVE METAL SALT + HYDROGEN Example: 2HNO3(aq) + Mg(s) Mg(NO3)2(aq) + H2(g) 3. ACID + METAL CARBONATE SALT + WATER + CARBON DIOXIDE Example: H2SO4(aq) + Na2CO3(s) Na2SO4(aq) + H2O(l) + CO2(g) 4. METAL DISPLACEMENT Example: Pb(NO3)2(aq) + Zn(s) Zn(NO3)2(aq) + Pb(s) 5. PRECIPITATION Example: Pb(NO3)2(aq) + 2KI(aq) PbI2(s) + 2KNO3(aq) 6. REDOX (METAL DISPLACEMENT IS ONE EXAMPLE) Example: See number 4. 7. DECOMPOSITION Example: CaCO3(s) CaO(s) + CO2(g) 8. COMBINATION (SYNTHESIS) Example: 2Na(s) + Cl2(g) 2NaCl(s) 9. DEHYDRATION Example: CuSO4.5H2O(s) CuSO4(s) + 5H2O(l) 10. COMBUSTION Example: 2C2H6(g) + 7O2(g) 4CO2(g) + 6H2O(l) Energy Changes in Chemical Reactions:

25. Name covalent compounds given their formulae

1. The first element keeps its name. 2. If there is more than one atom of the first element in the formula, use a prefix. 3. Always use a prefix for the second element, even if there is only one atom. The end of its name becomes '—ide'. Number of Atoms in Compound Prefix on the Name of the Element 1 mono-* 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca-

31. Identify social, ethical and environmental issues associated with the production of Biopol, a biopolymer

1. Where do most of the plastics we use come from? • The main source of synthetic plastics is crude oil. • Coal and natural gas • Petrol, paraffin, lubricating oils and high petroleum gases are produced during the refining of crude oil. These gases are broken down into monomers. Monomers are chemical substances consisting of a single molecule • Natural 'plastic products' occur in such things as animals' horns, animals' milk, insects, plants and trees. 2. Which common plastics are recyclable? #1 - PET (Polyethylene Terephthalate) - found in most water and pop bottles, and some packaging. #2 - HDPE (High-Density Polyethylene) - used to make milk jugs, detergent and oil bottles, toys, and some plastic bags. #3 - PVC (Polyvinyl Chloride) - PVC is a soft, flexible plastic used to make clear plastic food wrapping, cooking oil bottles and children's and pets' toys. #4 - LDPE (Low-Density Polyethylene) - found in shrink wraps, dry cleaner garment bags, squeezable bottles, and the type of plastic bags used to package bread. #5 - PP (Polypropylene) - Polypropylene plastic is tough and lightweight. It serves as a barrier against moisture, grease and chemicals. #6 - PS (Polystyrene) - most often used to make disposable styrofoam drinking cups, take-out "clamshell" food containers, egg cartons and plastic picnic cutlery. #7 - Other (BPA, Polycarbonate and LEXAN) - The #7 category was designed as a catch-all for polycarbonate (PC) and "other" plastics. 3. What is landfill and where is the closest landfill to Sydney? Landfill is the disposal of waste material by burying it. The closest landfill to Sydney is Greenwood, St Ives. 4. What is the problem with non-biodegradable plastics? • In the Ocean, it can harm fish, seabirds and other marine life. Animals can eat the plastic and may strangle them or experience digestion problems • In the land, it can stay in landfill and take up space much longer than biodegradable materials. Some of this will make its way to forests, fields and the sea 5. What are microplastics and what issues are they causing for marine ecosystems? Microplastics are extraordinarily small pieces of plastic that are in the environment resulting in the discarding of consumer products and industrial waste. Plastic is man-made and manufactured, meaning it is not natural. Marine animals can become entangled, exposed to chemicals and ingest the plastics. 6. What is biopol, what is its chemical structure and how is it made? Biopol is an environmentally friendly and biodegradable plastic produced by plant sugars and glucose from sweet potatoes, starch and vegetable oil. Biopol can be decomposed by bacteria which will reduce pollution. 7. Will biodegradable plastics solve the environmental problems associated with plastics? Biodegradable plastics can help in assisting plastic problems, however it cannot fix the problem entirely. Biodegradable products require specific conditions for it to biodegrade properly which are micro-organisms, temperature and humidity. If not managed properly, it can make the environment worse than standard plastics. When biodegradable plastics are put into landfill, it can produce harmful greenhouse gases when breaking down. 8. What can we personally do to help address the plastics problem? • Don't use plastic at all - Stop buying water bottles • Use less plastic • Use recyclable plastic products • Biodegradable plastics • Plastic bag tax - Customers bring in their own fabric bags

17. Identify and write word and symbol equations for combustion reactions

A combustion reaction is when a substance reacts with oxygen and releases a huge amount of energy in the form of light and heat. A combustion reaction always has oxygen as one reactant. The second reactant is always a hydrocarbon, which is a compound made up of carbon and hydrogen. A combustion reaction also always produces CO2 and H2O. C3H8 + O2 = CO2 + H2O Example: 2C2H6(g) + 7O2(g) 4CO2(g) + 6H2O(l) Balancing combustion reactions is easy. First, balance the carbon and hydrogen atoms on both sides of the equation. Then, balance the oxygen atoms. You balance oxygen after carbon and hydrogen because it is always standing alone as O2, and it is easier to balance than H and C. It's usually better to start balancing the harder things first, then the easier things after. Finally, balance anything that has become unbalanced.

22. Explain covalent bonding (sharing of electrons between non-metal atoms)

A covalent bond is formed between non metal atoms, which combine together by sharing electrons. Covalent compounds have no free electrons and no ions so they don't conduct electricity. The binding arises from the electrostatic attraction of their nuclei for the same electrons. A covalent bond forms when the bonded atoms have a lower total energy than that of widely separated atoms. Molecules that have covalent linkages include the inorganic substances hydrogen, nitrogen, chlorine, water, and ammonia (H2, N2, Cl2, H2O, NH3) together with all organic compounds. In structural representations of molecules, covalent bonds are indicated by solid lines connecting pairs of atoms

5. Recall common polyatomic ions and give some examples of their compounds

A polyatomic ion, also known as a molecular ion, is a charged chemical species (ion) composed of two or more atoms covalently bonded or of a metal complex that can be considered to be acting as a single unit. Polyatomic ions are everywhere! Bicarbonate ions, \text{HCO}_3^-HCO3−H, C, O, start subscript, 3, end subscript, start superscript, minus, end superscript, help maintain the pH level of our blood, while phosphates, \text{PO}_4^{3-}PO43−P, O, start subscript, 4, end subscript, start superscript, 3, minus, end superscript, are extremely important in various metabolic processes. Being familiar with the names, charges, and formulas of the most common polyatomic ions will be helpful for recognizing ionic compounds and predicting their reactivity. The following table lists some of the common polyatomic ions. FormulaHg2+2NH+4NO−2NO−3SO2−3SO2−4HSO−4OH−CN−PO3−4HPO2−4H2PO−4NameMercury(I)AmmoniumNitriteNitrateSulfiteSulfateHydrogen sulfate (bisulfate*)HydroxideCyanidePhosphateHydrogen phosphateDihydrogen phosphateFormulaSCN−CO2−3HCO−3ClO−ClO−2ClO−3ClO−4C2H3O−2(or CH3COO−)MnO−4Cr2O2−7CrO2−4O2−2C2O2−4NameThiocyanateCarbonateHydrogen carbonate (bicarbonate*)HypochloriteChloriteChloratePerchlorateAcetatePermanganateDichromateChromatePeroxideOxalate (refer to ques in doc)

28. Identify the main three forms of radioactivity (alpha, beta and gamma)

Alpha radiation - ɑ Alpha radiation is the least penetrating. It can be stopped (or absorbed) by a sheet of paper. Ionisation is useful for smoke detectors. Radioactive americium releases alpha radiation, which ionises the air inside the detector. Smoke from a fire absorbs alpha radiation, altering the ionisation and triggering the alarm. these are fast moving helium atoms. Beta radiation - β Beta radiation can penetrate air and paper. It can be stopped by a thin sheet of aluminium. Beta radiation is used for tracers and monitoring the thickness of materials. these are fast moving electrons. Doctors may use radioactive chemicals called tracers for medical imaging. Certain chemicals concentrate in different damaged or diseased parts of the body, and the radiation concentrates with it. Radiation detectors placed outside the body detect the radiation emitted and, with the aid of computers, build up an image of the inside of the body. Radiation is used in industry in detectors that monitor and control the thickness of materials such as paper, plastic and aluminium. The thicker the material, the more radiation is absorbed and the less radiation reaches the detector. It then sends signals to the equipment that adjusts the thickness of the material. Check your understanding of this by watching the simulation. Gamma radiation - γ Gamma radiation is the most penetrating. Even small levels can penetrate air, paper or thin metal. Higher levels can only be stopped by many centimetres of lead, or many metres of concrete. Gamma radiation is used in the treatment of cancer, testing equipment and sterilising medical instruments. these are photons, just like light, except of much higher energy

1. Describe the structure of atoms, including electron configurations

Atoms consist of electrons surrounding a nucleus that contains protons and neutrons. Neutrons are neutral, but protons and electrons are electrically charged. Protons have a relative charge of +1, while electrons have a relative charge of -1. The number of protons in an atom is called its atomic number. In the periodic table atoms are arranged in atomic number order. Electrons are arranged in energy levels or shells, and different energy levels can hold different numbers of electrons. The electronic structure of an atom is a description of how the electrons are arranged, which can be shown in a diagram or by numbers. There is a link between the position of an element in the periodic table and its electronic structure.

27. Identify the use of bicarb soda (NaHCO3) in cooking

Bicarbonate of soda, or baking soda, is an alkali which is used to raise soda breads and full-flavoured cakes such as gingerbread, fruit cake, chocolate cake and carrot cake. It needs an acid (as well as moisture) to activate it so is often combined with cream of tartar, yoghurt, buttermilk or milk.

29. Identify medical and industrial uses of radioactivity

Examples of the uses of radioisotopes in medicine: - X-rays - Trace aspects of blood flow and body chemistry - Technetium-99 for medical imaging (tracers - see inside - diagnose) - Radiotherapy - kill cancer cells Examples of the uses of radioisotopes in industry: - Produce electricity - Smoke detector - Keeps food safe - prevents food poisoning and keeps food fresh longer - Measure liquid levels and make sure bottles are filled - Nuclear gauges - density and depth of road surface - Oil and gas companies - locate underground wells and look for damaged pipes - Test aircraft parts before assembled

24. Recall the formulae of common covalent compounds, e.g. water, carbon dioxide, ammonia, methane, sulphur dioxide, carbon monoxide

Formula Common Name Prefix Name CH4 methane carbon tetrahydride NH3 ammonia nitrogen trihydride H2O water dihydrogen monoxide PCl3 - phosphorus trichloride CH3CH2OH - ethanol O3 - ozone H2 - hydrogen HCl - hydrogen chloride CO2 - carbon dioxide SO2 - sulphur dioxide

3. Explain why ions form and use the periodic table to identify the valency of ions in different groups of the table

Ions are electrically charged particles formed when atoms lose or gain electrons. They have the same electronic structures as noble gases. Metal atoms form positive ions, while non-metal atoms form negative ions. The strong electrostatic forces of attraction between oppositely charged ions are called ionic bonds. Valency is the combining power of an element. Elements in the same group of the periodic table have the same valency. The valency of an element is related to how many electrons are in the outer shell. The noble gases have the valency 0 as they do not usually combine with other elements. To write the chemical formula for a compound it is best to use the S.V.S.D.F system. Step one: Write down the symbols of both the elements involved. Step two: Beneath each symbol, write its valency. Memorise the table above to help you. Step Three: Swap the valencies over. Step Four: If the valencies can be simplified, divide them both by the smaller of the two numbers. If one of the numbers is already one, then they cannot be divided and simplified any further. Step Five: Write the formula.

15. Identify that chemical reactions are either endothermic or exothermic

Most chemical reactions are accompanied by a temperature change: Exothermic: release heat and feels hotter. E.g. combustion Endothermic: absorb heat and feel colder. E.g. chemical ice packs

9. Make and test a natural indicator

Plants You Can Use To Test pH BeetsA very basic solution (high pH) will change the color of beets or beet juice from red to purple. 'Black' BerriesBlackberries, black currants, and black raspberries change from red in an acidic environment to blue or violet in a basic environment. BlueberriesBlueberries are blue around pH 2.8-3.2, but turn red as the solution becomes even more acidic. Carrots Cherries Cherries and their juice are red in an acidic solution, but turn blue to purple in a basic solution.

4. Explain ionic bonding and the formulae of ionic compounds

Positive and negative ions attract one another and bind together forming a new substance. This is called ionic bonding. For example: Sodium chloride consists of Na+ ions and Cl- ions bound together. Ionic bonding occurs between positive and negative ions, which attract each other and bind together to form ionic compounds. For example, sodium chloride consists of Na+ ions and Cl- ions bound together. Name of ion Formula and charge Chloride Cl− Sodium Na+ Sulfate SO42− Magnesium Mg2+ Calcium Ca2+ Potassium K+ Carbonate CO32− Bromide Br− (refer to cation and anions table)

30. Research problems associated with the use of radioactivity

Possible harmful effects of using radioisotopes: - Damage surrounding material (beta) - Biological damage - different kinds - alpha stops hard and deposits all energy into one place - Can cause birth defects - Reducing of lymphocyte in the blood - Hair loss

21. Explain factors which affect the rate of a chemical equation

Reactions may occur when reactant particles collide with each other. The speed or rate of a chemical reaction is measured by how quickly reactants are converted into products. In a firework, there is rapid conversion of reactants into products. In the browning of an apple, the conversion is much slower. The collision theory seeks to explain how reactants interact during the course of a chemical reaction to form products. From the collision theory comes a qualitative explanation of the factors known to alter the rate of chemical reactions. These factors are: particle size concentration temperature the presence of a catalyst

18. Use solubility rules to determine whether a precipitate will form in a chemical reaction

Solubility Rules All salts of the group I elements (alkali metals = Na, Li, K, Cs, Rb) are soluble. NO3: All nitrates are soluble. Chlorate (ClO3-), perchlorate (ClO4-), and acetate (CH3COO- or C2H3O2-, abbreviated as Oac-) salts are soluble. Cl, Br, I: All chlorides, bromides, and iodides are soluble except those of silver, mercury, and lead (e.g., AgCl, Hg2Cl2, and PbCl2). SO42: Most sulfates are soluble. Exceptions include BaSO4, PbSO4, and SrSO4. CO32: All carbonates are insoluble except NH4+ and those of the Group 1 elements. OH: All hydroxides are insoluble except those of the Group 1 elements, Ba(OH)2, and Sr(OH)2. Ca(OH)2 is slightly soluble. S2: All sulfides are insoluble except those of the Group 1 and Group 2 elements and NH4+. Solubility Rules for Ionic Compounds The rules are meant as a guide only. There are exceptions to these rules. 1. Salts of the alkali metals are soluble. (Note: The alkali metals are in group 1.) e.g. If M = Li, Na or K, then MX, M2X, M3X, etc. are soluble regardless of what X is. 2. Ammonium (NH4+ ) salts are soluble. e.g. NH4 X, ( NH4 )2X, (NH4 )3X, etc. are soluble regardless of what X is. 3. Nitrates NO−3 are soluble. e.g. MNO3, M(NO3)2, M(NO3)3, etc. are soluble regardless of what M is. 4. Halides i.e. chlorides (Cl− ), bromides (Br− ) and iodides (I− ) are soluble except for the halides of lead (Pb2+), mercury (Hg+ and Hg2+2 ) and silver (Ag+). e.g. If X = Cl, Br or I, then MX, MX2, MX3, etc. are soluble unless M = Pb, Hg or Ag. 5. Sulfates (SO24− ) are soluble except for the sulfates of calcium, strontium, barium, silver mercury and lead. e.g. M2SO4, MSO4, M2(SO4)3, etc. are soluble unless M is from group 2 (the alkaline earths) or M = Pb, Hg or Ag. 6. Carbonates (CO23− ), phosphates (PO34− ) and sulfides (S2− ) are insoluble except for (i) the carbonates/phosphates/sulfides of the alkalis (because of Rule 1), and (ii) ammonium carbonate/phosphate/sulfide (because of Rule 2). − 7. Hydroxides (OH ) are insoluble or slightly soluble except for the hydroxides of the alkalis (because of Rule 1). Note: The hydroxides of group 2 (the alkaline earth metals) are slightly soluble. Virtually all other hydroxides are insoluble.

7. Identify and test household substances to determine whether they are acid, base or neutral

Testing household substances Note: Acidic substances turn blue litmus red and produce hydrogen ions in solution Basic substances turn red litmus blue and produce hydroxide ions in solution Neutral substances do not change the colour of red or blue litmus Substance Result with red and blue litmus Acidic, basic or neutral Milk Blue: no change Red: no change Neutral Coke Blue: red Red: no change Acidic Sugar Solution Blue: no change Red: no change Neutral Sodium Carbonate Blue: no change Red: blue Basic Lemon Juice Blue: red Red: no change Acidic Hydrochloric Acid Blue: red Red: no change Acidic Sodium Hydroxide Blue: no change Red: blue Basic Antacid Blue: no Red: no Neutral Pineapple Juice Blue: no change Red: blue Acidic Cloudy Ammonia Red: blue Blue: no change Basic Sprite Red: no change Blue: red Acidic Mylanta Red: blue Blue: no change Basic Aspro Clear Red: no change Blue: red Acidic The pH Scale pH = power of hydrogen and represents the concentration of hydrogen ions in a solution. At 25 degrees 0 ---------------------7----------------------14 0 = strong acids 7 = neutral 14 = strong bases 0 7 acids solutions getting weaker 14 7 basic solutions are getting weaker [H+] = [OH-] Acids produce H+ ions in solution Bases produce OH- ions in solution [] = concentration pH = -log10[H+] ie/ every step along the scale = 10x difference in concentration e.g. pH 4 solution is 100 times weaker than a pH 2 solution. Valency = charge on an ion e.g. the valency of sodium is +1

6. Explain what conversation of mass means in relation to chemical reactions

The Law of Conservation of Mass says that in chemical reactions no matter is lost or gained. The law of conservation of mass means that during chemical change there is no loss or gain of atoms. It is for this reason that we always balance chemical equations.

2. Use electron configurations to explain the structure of the periodic table

The noble gases (group 18) are the most stable elements because they have very stable electron configurations. All noble gases either have a full outer shell (He or Ne) or a stable octet (8 electrons) in their outer shells. All other elements participate in chemical reactions in order to become more stable. They do this by losing or gaining outer shell electrons until they have a noble gas electron configuration. There are two links between an atom's electronic structure and its position in the periodic table: The number of occupied shells is the same as the period number(row in the table) The number of electrons in the outer shell is the same as the group number (column in the table)

11. Recall the pH scale and perform a dilution experiment to observe a range of pHs

The pH Scale pH = power of hydrogen and represents the concentration of hydrogen ions in a solution. At 25 degrees 0 ---------------------7----------------------14 0 = strong acids 7 = neutral 14 = strong bases 0 7 acids solutions getting weaker 14 7 basic solutions are getting weaker [H+] = [OH-] Acids produce H+ ions in solution Bases produce OH- ions in solution [] = concentration pH = -log10[H+] ie/ every step along the scale = 10x difference in concentration e.g. pH 4 solution is 100 times weaker than a pH 2 solution. Universal indicator is widely used to measure pH. It is a mixture of different idicators and undergoes a series of colour changes over a range of pH values. Place 10ml of hydrochloric acid in one test tube then measure 1ml of the acid and transfer to other test tubesand add 9ml of water. Shake and repeat. Place 10 ml of water in 7. Measure 0ml of sodiu hydroxide into test tube 14 then repeat other steps It is possible to tell if a solution is acidic or alkaline by using an indicator. An indicator is a substance which has different colours when it is in acidic or alkaline conditions. Litmus is probably the most well-known indicator. This is red in acids and blue in alkalis. Litmus can be used as a liquid, or as litmus paper. Solutions of acids and alkalis can vary widely in their acidity and alkalinity. It is useful to know not just whether a solution is an acid or an alkali, but how acidic or how alkaline it is. To measure acidity and alkalinity, we can use the pH scale. The easiest way to do this is to use Universal indicator. This is a mixture of several different indicators, and can be used as a liquid or paper. It has many different colour changes. The colour of the Universal indicator shows the pH value of the solution. The pH scale runs from pH 0 to pH 14. Diagram of the PH scale Diagram of pH scale and universal indicator colours To get a more accurate measurement of the pH of a solution, we can use a pH meter. This device can measure the pH of a solution to 0.01 of a pH unit.

16. Perform an experiment to show energy changes in chemical reactions

Use a thermometer and measure temperatue of substance in water suc as magnesium ribbon, calcium chloride solid and sodium acetatw solid

19. Perform an experiment on precipitation reactions

Using spotting tiles with silver nitrate and odium hydroxide, sodium carbonate and barium nitrate

10. Perform an experiment to determine what makes a substance an acid or a base

Using: Plant indicator Hydrochloric acid Sulphuric acid Nitric acid Sodium hydroxide Potassium hydroxide Ammonium hydroxide

26. Define decomposition as a chemical reaction where a compound is broken down into smaller units

decomposition as a chemical reaction where a compound is broken down into smaller units

8. Define indicators as chemicals that have different colours when added to acids and bases

indicators as chemicals that have different colours when added to acids and bases

12. Recall the word equation for neutralisation acid + base salt + water

neutralisation acid + base salt + water