National 4 Unit 1 1. Rates of Reaction 2. Atomic Structure 3. Acids & Bases 4. Energy Changes Homework 1
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Homework 1 - Rates of Reaction Decide which of the following are True or False: 1. Increasing the temperature increases the rate of a reaction. 2. Lumps of calcium carbonate react faster than calcium carbonate powder, with acid. 3. A less concentrated acid reacts faster than a more concentrated one. 4. A catalyst can speed up the rate of a reaction. 5. Milk is more likely to turn sour at 0 o C than at 100 o C. 6. Small potatoes take longer to cook than large potatoes. 7. Plants grow faster in warm weather than in cold weather. 8. Compared with coal dust, lumps of coal burn very rapidly. 9. A catalyst can be recovered chemically unchanged at the end of a reaction. 10. Catalysts can be used in car exhaust systems to speed up the reactions which remove harmful gases. 11. Acetylene burns less rapidly in pure oxygen than in air. 12. Chips cook faster in oil at 300 o C than in oil at 100 o C. 13. A catalyst is used up during a chemical reaction. 14. Reactions involving gases go faster when the pressure is increased. 3
Homework 2 - Rates of Reaction 4
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Homework 3 - Rates of Reaction 1. 2. 6
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Homework 4 - Periodic Table Revision 1. Name 2 elements which are: a) Metals b) Non-metals c) Solid at room temperature d) Liquid at room temperature e) Gas at room temperature f) Naturally occur as compounds g) Naturally occur as elements h) Named after scientists. 2. The diagram below shows the periodic table. A B A C E D Which letter represents: a) A halogen b) An alkali metal c) A noble gas d) A transition metal 3. At room temperature (20 o C), decide whether the following are A. Solid B. Liquid C. Gas a) Oxygen b) Iodine c) Phosphorous d)hydrogen e) Calcium f) Bromine g) Mercury h) Argon 4. Which family of elements do the following elements belong to? A. the halogens B. the alkali metals C. the noble gases D. the transition metals a) Chlorine b) Fluorine c) Iron d) Argon e) Sodium f) Neon g) Potassium h) Copper 5. Why do potassium and sodium have similar chemical and physical properties? 8
6. Name 2 other elements with similar chemical properties. 9
Homework 5 Structure of the Atom 1. The atom is made up of three small particles, what are these particles called? 2. What is the name given to the core of the atom? 3. Copy and complete the following table: Subatomic particle Mass Charge Location in atom + ve Orbiting the nucleus 1 4. What is the charge in the nucleus of the atom? 5. Which particle if responsible for this charge? 6. Explain why an atom is neutral? 7. Label the particles in the following carbon atom: 10
Homework 6 Atomic Number & Mass Number 1. Explain what is meant by Atomic Number. 2. How can the Mass Number of an element be calculated? 3. Name the elements with the following Atomic Numbers: a) 23 b) 3 c)18 d) 28 e) 9 4. Copy and complete the following table: Element Symbol Element Name Atomic Number Mass Number No of Protons No of Neutrons No of Electrons Electron Arrangement Ne 22 N 7 Ca 40 4 9 2,2 14 6 89 36 14 14 5. Put the following elements in order by increasing atomic number: Nickel, Beryllium, Chlorine, Boron, Silver, Sulphur 6. The following table gives information about atoms. A The number of protons in the nucleus B The number of neutrons in the nucleus C The number of protons plus neutrons in the nucleus D The number of electrons outside the nucleus E The number of electrons in the outer energy shell a) Which letter represents 7 for halogens? b) Which 2 letters are the same in all neutral atoms? c) Which letter is the mass number of an element? 7. Name the elements with the following electron arrangements: a) 2,8,1 b) 2,8 c) 2,8,3 d) 2,4 e) 2,7 f) 2,8,4 g) Which two of these elements have similar chemical properties? 11
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Homework 7 Covalent and Ionic Bonding 1. Explain what is meant by a covalent bond. 2. What type of elements bond to form an ionic bond? 3. Properties for four different substances sodium chloride, copper bromide, aluminium and glucose are shown in the following table: Solubility in water Colour of solution Electrical conductivity in solid state Electrical conductivity in molten state P Q R S Soluble Insoluble Soluble Soluble Colourless - Blue Colourless Does not conduct Does not conduct Conducts Does not conduct Does not conduct Conducts Conducts Conducts a) Use the table to identify P, Q, R and S. b) State the type of chemical bonding in substances P, R and S. c) Explain why R and S only conduct electricity when molten. 4. Draw a labelled diagram of an experiment to test whether a substance is ionic or covalent. 5. The table below shows some properties of two chlorides: Chloride Melting point o C Boiling point o C Solubility in water XCl 801 1417 soluble YCl4-23 77 insoluble a) Which of these chlorides would you expect to be covalent? b) In which group of the periodic table would you expect to find element X? 13
Homework 8 Chemical Formulae 1. Write the formula for the following compounds using prefixes: a) Sulfur trioxide b) Dinitrogen monoxide c) Carbon tetrachloride d) Sulfur hexafluoride 2. Write the chemical formula for the following covalent compounds using valencies: a) Hydrogen oxide b) Phosphorous fluoride c) Nitrogen chloride d) Sulfur chloride 3. Write the formula for the following ionic compounds using valencies: a) Sodium bromide b) Potassium chloride c) Magnesium chloride d) Aluminium oxide 4. Write the formula for the following ionic compounds a) Lead(II) bromide b) Copper(I) oxide c) Iron(II)chloride d) Nickel(II) fluoride Homework 9 Word Equations and Formulae Write the word equation for each statement and then write out the reaction using formulae. 1. Nitrogen and hydrogen react together to form ammonia (NH3). 2. Copper (II) chloride reacts with iron to form copper and iron chloride. 3. During photosynthesis carbon dioxide and water join together to from glucose (C6H12O6) and oxygen. 4. When carbon is burned in a good oxygen supply the product formed is carbon dioxide. 5. Iron ore and carbon monoxide react in a blast furnace to form iron and carbon dioxide. 14
Homework 10 - Acids and Bases 1. a) Name 2 oxides which dissolve in water to give acids. b) Name 2 oxides which dissolve in water to give alkalis. 2. Copy and complete the following When non-metal oxides dissolve in water they turn ph paper But soluble metal oxides turn it. 3. Write a word equation for these elements burning in Oxygen. a) Carbon b) Sodium 4. Write the above equations as chemical equations. 15
Homework 11 - Acids and Bases 1. Over the last 50 years a game keeper has been keeping a log of the number of trout caught in his loch and the mean ph of the loch water. Here are some of his notes. 1960-69, 1000 fish caught and the mean ph was 6.4. In the next 10 years the mean ph was 5.6 and only 750 fish were caught. In 1980-1989 the mean ph was 4.5 and 200 trout were caught. Only 10 trout caught in 1990-1999 and the acidity has increased to ph 3.6. In 2000-2009, the ph has dropped to 3.1 and no trout caught. a) Put the above information into a table with suitable headings. b) Looking at the results in your table, why do you think the number of trout caught has gone down so much? 2. What effect does acid rain have on a) Buildings b) Soil and plants c) Animal life (e.g. fish)? 3. Copy and complete the following The ph scale is a range. have a ph of less than 7 and have a ph of more than 7. Neutral solutions have a ph equal to 4. Pure water Sodium Citric acid Potassium hydroxide Hydroxide Salt water Alka-seltzer Vinegar Nitric acid Ammonia solution Coca-cola Lemon juice Hydrochloric From the above table choose a) 2 acids used in the laboratory. b) 2 alkalis used in the laboratory. c) 2 acids used in the home. d) 2 alkalis used in the home. acid 16
Homework 12 - Naming Salts A salt is a compound made when and a reacts with and b to neutralise it. Complete the following word equations Calcium + Calcium + water hydroxide chloride Calcium + Calcium + hydroxide sulfate potassium + Hydrochloric + hydroxide acid potassium + sulfuric + hydroxide acid Name the salt made in each case when: a) sodium hydroxide is added to hydrochloric acid b) sodium hydroxide is added to sulfuric acid. 17
Homework 13 - Energy changes 1. Copy and complete a) Chemical reactions which give out energy are called b) Chemical reactions which take in energy are called. c) In an reaction the temperature of the reaction mixture rises. d) In an.. reaction the temperature of the reaction mixture falls e) Burning a fuel in air is an reaction f) Neutralisation is an.. reaction g) Dissolving sherbet in water is an reaction. 2. Spirit burners can be used to burn liquid fuels safely in the lab. Plan an investigation to compare the amount of energy transferred when different fuels are burnt. 3. Is respiration an exothermic or endothermic reaction? How do you know? 18