Copper & Aluminum in Water Lab Answers
Aim To perform and observe the action of water on quicklime, action of heat on ferrous sulphate crystals, reaction of iron nails kept in copper sulphate solution, reaction between sodium sulphate and barium chloride solutions and classify the reaction. Materials Required Calcium oxide quicklime , distilled water, borosil beaker, test tube, glass rod, dropper, red and blue litmus paper strips. Theory When calcium oxide quicklime is dissolved in water, it forms calcium hydroxide slaked lime.
The reaction is highly exothermic, i. This reaction may be represented in the form of a chemical reaction as follows: Note Calcium hydroxide is basic in nature.
Aluminum and copper chloride lab procedure manual
Therefore, it turns moist red litmus paper blue. If we pass CO 2 through clear calcium hydroxide solution lime water , it turns milky due to the formation of a white precipitate insoluble calcium carbonate.
In reaction i , two compounds-quicklime and water combine to give a single product slaked lime. So, this is an example of combination reaction. Hence, it may be stated that when two or more substances react together to form a single product, is called a combination reaction. Also, it has been observed that a large amount of heat is evolved alongwith the formation of products. Such type of reactions which are accompanied by the evolution of heat, are called exothermic reactions.
Observation The hissing sound is produced and solution becomes hot. The heat is evolved during the reaction which raises the temperature of the reaction mixture. On putting a few drops of the solution on red and blue litmus paper, it is observed that only red litmus paper turns blue, no changes occur in blue litmus paper. As heat is evolved, the reaction is exothermic. Result The reaction between quicklime and water to form slaked lime is a combination reaction as well as exothermic reaction.
Question 1. What is combination reaction?
CBSE Class 10 Science Lab Manual – Types of Reactions
Answer: A reaction in which two or more substances combine to form a single product compound is called a combination reaction.
Question 2. What is calcium oxide commonly called? Answer: Calcium oxide CaO commonly known as quicklime. Question 3. When slaked lime is brought in contact with red litmus paper, what do you observe? Answer: We observe that red litmus paper turns blue. From this, we can conclude that slaked lime is basic in nature. Question 4. A small amount of quicklime is taken in a beaker.
Water is added slowly to the beaker. What observation would you note down? Answer: When water is added slowly in a quicklime, hissing sound is produced and the solution becomes hot. Question 5.
Name the reaction between calcium oxide and water. Answer: The reaction between calcium oxide and water is known as combination reaction.
Question 6. Why should we not touch iron container in which CaO reacts with H 2 O? Answer: We should not touch iron container in which CaO reacts with H20 because iron container will be very hot as the reaction is exothermic. Question 7. Write the product formed when quicklime reacts with water. Answer: Quicklime reacts with water to give calcium hydroxide Ca OH 2 , ie.
Question 8. What is the effect of temperature on the solubility of calcium hydroxide? Answer: Solubility of calcium hydroxide or slaked lime decreases with increase in temperature.
Question 9. Is the reaction between quicklime and water exothermic or endothermic? Answer: As heat energy is released during the reaction, therefore it is an exothermic reaction. Question Name the chemical formula and chemical name of slaked lime.
Most of the combination reactions are exothermic in nature. Give reason. Answer: Most of the combination reactions are accompanied by liberation of heat energy. This is known as exothermicity.
For example, when natural gas burns in the oxygen of air, it forms carbon dioxide and water vapour. A large amount of heat is also produced. Give an example of a combination reaction. Answer: When magnesium ribbon burns in air, it forms magnesium oxide. This is an example of combination reaction.
How is lime water prepared? Answer: Mix calcium oxide with water, shake the mixture well and leave it to stand for a while. Collect the clean solution on top. This is lime water. What is the suspension of slaked lime in water commonly called? Answer: The suspension of slaked lime in water is commonly called milk of lime.
Why lime water turns milky when CO 2 gas is passed through a test tube containing lime water?
Answer: Lime water turns milky due to the formation of insoluble precipitate of calcium carbonate CaCO 3. Avinav takes 2 mL of clear liquid from the mixture of quicklime with water and then he breath out in it. What would he observed?
Answer: The filtrate turns milky. Answer: When water is mixed with CaO, lime water is formed.
Materials Required Ferrous sulphate crystals 2g , boiling tube, test tube holder, safety glass goggle , Bunsen burner, blue and red litmus paper strips. Theory The ferrous sulphate crystals are actually ferrous sulphate heptahydrate FeSO 4.
They contain seven molecules of water of crystallisation. These crystals are green in colour. When this anhydrous ferrous sulphate is heated, it decomposes to give ferric oxide, sulphur dioxide and sulphur trioxide.
What Do Copper(II) Chloride and Aluminum Form When They Are Combined?
So, this is a decomposition reaction. It is actually a thermal decomposition reaction. On combining Eqs. Result Heating of ferrous sulphate crystals is a decomposition reaction and it decomposes to give ferric oxide Fe 2 O 3 , sulphur dioxide SO 2 and sulphur trioxide SO 3. What is decomposition reaction? Answer: When a compound decomposes to give two or more simpler substances, it is a decomposition reaction.
When lead nitrate Is heated, it decomposes as shown below:. Write the formula of ferrous sulphate crystals. Answer: FeSO 4. What is the common name of ferrous sulphate crystals? Answer: The common name of ferrous sulphate crystals are green vitriol.
When FeSO 4 crystals are strongly heated, it given off some gases. Name these gases. Answer: These gases are sulphur dioxide SO 2 and sulphur trioxide SO 3 , which have suffocating smell like burning sulphur. The heating of ferrous sulphate FeSO 4.
Answer: The heating of FeSO 4. What happens when crystals of ferrous sulphate are heated? Answer: Ferrous sulphate crystals FeSO 4. On heating ferrous sulphate crystals, two gases are evolved. Which gas produces fumes of sulphuric acid when it comes in contact with moist air? Answer: Sulphur trioxide gas produces fumes of sulphuric acid when it reacts with water vapour present in the air. What residue is formed when hydrated ferrous sulphate crystals are heated?
Write the use of decomposition reaction. Answer: The decomposition reactions carried out by electricity, are used to extract several metals from their naturally occurring compounds like chlorides or oxides.