Bellahouston Academy S2 CHEMISTRY. Part 1 Matter HOMEWORK

Transcription

1 Bellahouston Academy S2 CHEMISTRY Part 1 Matter HOMEWORK Name May 2012

2 HOMEWORK SHEET 1: States of Matter There are three states of matter: solid liquid gas Heat a solid to its melting point and it will become a liquid and heat a liquid to its boiling point and it will become a gas. melting point boiling point 1. Against each of the diagrams below write the name of the state of matter represented and record two things that describe the arrangement of the particles in that state The planet Mars has a very thin atmosphere consisting of carbon dioxide, nitrogen and argon, with trace amounts of oxygen and water. During the Martian winter the temperature can drop to -133 C. Record in the table below the state of these materials in the Martian atmosphere at that temperature? Material Melting Point Boiling Point State (solid, liquid or gas?) Carbon dioxide -57 C -78 C Nitrogen -210 C -196 C Argon -189 C -186 C Oxygen -218 C -183 C Water 0 C 100 C

3 HOMEWORK SHEET 2: Elements Read the following passage and answer the questions below: Elements If you heat a piece of bread, or a piece of wood, for long enough you will be left with a black solid that is called carbon. It is one of the simplest chemicals. It is called an element. The word elementary means simple. Carbon is called an element because it is only made up of carbon atoms it can t be broken down into anything simpler. Copper is another example of an element it is made up only of copper atoms. Each element has a name and a symbol. C is the symbol for carbon and Cu is the symbol for copper. There are just over 100 different elements and they are listed in a chart called the Periodic Table. Around 90 elements have been found in nature. The rest have been made by scientists. 1. Why is carbon an element? 2. What name is given to the chart which lists the elements? 3. How many elements are there? 4. How many kinds of atom are found in a lump of copper? Why is water not listed in the Periodic Table of the Elements?

4 HOMEWORK SHEET 3: Groups in the Periodic Table The main vertical columns within the Periodic Table are called groups. These are numbered 1 to 8 (although the last group is sometimes numbered as Group 0). Elements in the same group have similar chemical properties. The rows are called periods. The Periodic Table of the elements /8 Consider the table below: A Carbon (C) B Lithium (Li) C Potassium (K) D Neon (Ne) E Magnesium (Mg) F Mercury (Hg) G Platinum (Pt) H Bromine (Br) I Rhodium (Rh) Which box (or boxes you must name them all) in the table shows: 1. an alkali metal? 2. a halogen? 3. a noble gas? 4. a transition metal? 5. a non-metal? 6. an element which reacts vigorously with water? 7. an element which is a very unreactive gas? 8. three elements in the same period of the periodic table? 9. an element which has similar chemical properties as chlorine? 10. a metal element which conducts electricity? 11. a non-metal element which conducts electricity?

5 HOMEWORK SHEET 4: Elements and Compounds Atoms join together to form molecules. In elements all the atoms in the molecule are the same. In compounds the atoms in the molecule are different. Write beside each box whether it contains an element, a compound, a mixtures of elements, a mixture of compounds, or a mixture of elements and compounds: A A B B C C D D E E F F G G H H

6 HOMEWORK SHEET 5: Naming Compounds Compounds are molecules containing the atoms of different elements joined together chemically. The name of a compound containing 2 elements only always ends in the letters -ide. If a compound contains 3 elements, and one of them is oxygen, then its name usually ends in the letters ite or -ate. 1. Name the elements present in the following compounds: Compound hydrogen sulphide Elements Present zinc nitrate potassium chloride barium nitride magnesium chlorate calcium bromide lithium carbonate sodium nitrite nitrogen hydride phosphorus chloride iron sulphite 2. Name the compounds that would contain the following elements: Elements copper and sulphur Compound iron and chlorine potassium and oxygen potassium, carbon and oxygen zinc, sulphur and oxygen oxygen, nitrogen, and lithium

7 HOMEWORK SHEET 6: Breaking Compounds Energy is needed to break a compound into its elements. Using electricity to break up a compound into its elements is known as electrolysis. Read the following passage and answer the questions below: Electrolysis of Common Salt Common salt is a substance called sodium chloride. Salt dissolves in water to form a solution. During electrolysis (when an electric current is passed through this solution) a green gas called chlorine is given off at the positive electrode and sodium is formed at the negative electrode. The sodium then reacts with water in the solution to give off hydrogen gas and sodium hydroxide which remains in solution Cl - Na + 1. List three compounds mentioned above: 2. List three elements mentioned above: 3. Explain why electricity needed to form the elements sodium and chlorine from the compound sodium chloride. 4. A reaction which needs energy is called endothermic. A reaction which gives out energy is called exothermic. Electrolysis is endothermic. If sodium metal is added to a jar of chlorine then sodium chloride will form. Is this reaction likely to be endothermic or exothermic?

8 HOMEWORK SHEET 7: Solutions and Mixtures 1. Give the meaning of the following words: Solute Solvent Dilute Concentrated Saturated 2. Sometimes, but not always, when a material is insoluble in water it can be dissolved in an organic solvent. Suggest an organic solvent you might use to form a non-aqueous solution with oil based paints. 3. Sodium carbonate is an important household chemical because when used with soap it can stop scum forming. Sodium carbonate is obtained in the United States from large natural despots which are mined but this raw material (known as Trona) also contains a lot of sand and soil. Explain below how you could obtain a pure dry sample of sodium carbonate from Trona. (Hint: sodium carbonate must be soluble if it is used in washing!) Draw a diagram of the apparatus you would use.

9 HOMEWORK SHEET 8: Some Analytical Techniques 1. In separating a mixture we must look for differences between the materials in the mixture. (For example: iron is magnetic but sulphur is not, salt is soluble but sand is not). The same can be applied to a mixture of liquids. A mixture of liquids with different boiling points can be separated by distillation. Distillation: Mixture of alcohol & water Condenser Alcohol has a boiling point of 79 C and water, of course, boils at 100 C. What temperature would you select to remove alcohol from a mixture of alcohol and water by distillation? 2. A solution can have several materials dissolved in it. Paper chromatography These can be separated out using chromatography An unknown solution (P) containing several dissolved materials were spotted onto chromatographic paper with several standard solutions of known materials (A, B, C, D, and E). The resulting chromatogram is shown below: some hours later What materials were present in solution P?