c) Draw a sketch of a graph illustrating the relationship between the volume of a fixed mass of a gas and its absolute temperature at a constant pressure.

You're on a roll — Here are the solutions to the questions: 13. c) Draw a sketch of a graph illustrating the relationship between the volume of a fixed mass of a gas and its absolute temperature at a constant pressure. This relationship is described by Charles' Law, where volume is directly proportional to absolute temperature. ` Volume (V) ^ | / | / | / | / +-----------> Absolute Temperature (T) 0 ` 14. a) Hydrogen can reduce Copper (II) Oxide but cannot reduce Aluminium Oxide. Explain. Hydrogen can reduce oxides of metals that are less reactive than itself. Copper is less reactive than hydrogen, so hydrogen can reduce copper (II) oxide. Aluminium is more reactive than hydrogen, so hydrogen cannot reduce aluminium oxide. b) Nitric (V) acid is not used to prepare hydrogen gas. Explain. Nitric (V) acid is a strong oxidizing agent. When it reacts with metals, it oxidizes the hydrogen gas produced to water. Instead of hydrogen, oxides of nitrogen (like NO_2, NO, or N_2O) are typically formed. c) When water reacts with potassium metal, the hydrogen gas produced ignites explosively on the surface of water. i) What causes this ignition? The reaction between potassium and water is highly exothermic, releasing a large amount of heat. This heat is sufficient to ignite the hydrogen gas produced, causing it to burn explosively. 15. Study the diagram below and answer the questions that follow. a) State and explain the observations made in: i) Combustion Tube (I) Observation: The blue solid turns white, and a colorless liquid condenses on the cooler parts of the tube. Explanation: Hydrated copper (II) sulphate (CuSO_4 · 5H_2O) loses its water of crystallization upon heating, forming anhydrous copper (II) sulphate (white solid) and steam (which condenses to liquid water). ii) Combustion Tube (II) Observation: The black solid (iron powder) turns red-brown/grey, and a colorless gas is produced. Explanation: Steam (from Tube I) reacts with hot iron powder to form iron (II, III) oxide (Fe_3O_4) and hydrogen gas. 3Fe(s) + 4H_2O(g) heat Fe_3O_4(s) + 4H_2(g) b) Give a reason why ice is mixed with Sodium Chloride. Mixing ice with sodium chloride creates a freezing mixture that achieves a temperature significantly below 0^. This is done to effectively condense any water vapor or other volatile liquids produced in the reaction, ensuring efficient collection of liquid W. c) State one industrial use of Hydrogen gas. Hydrogen gas is used in the Haber process for the industrial manufacture of ammonia. (Other uses include hydrogenation of oils to make margarine, and as a fuel). 16. Use the information to answer questions that follow: Solid E was put in a boiling tube and 10cm^3 of distilled water was added. The mixture was shaken thoroughly and the solid dissolved. The resulting solution was divided into five portions. a) Place about a half spatula full of the solid into a clean dry test tube. Heat gently. | Observation | Inference | | :------------------------------------------------------------------------------------------------------ | :-------------------------------------------- | | The solid melts, and a colorless liquid condenses on the cooler parts of the test tube. The solid may change color (e.g., blue to white) or remain white. | The solid is a hydrated compound. | What's next?