The student wanted to be sure he had made Calcium Oxide. He crushed some heated limestone and added water. The mixture got hot. The student cooled the mixture and filtered it. This gave a colourless solution and a white solid that was left in the filter paper. The student added unversial indicator to the solution and it turned purple. Explain how the students observations show that he had made some Calcium Oxide by heating limestone.
Its in for tommorow
CaO + H2O --> Ca(OH)2 and this reaction is exothermic and it is a basic solution so the universal indicator would show that.
What do you mean by "exothermic"?
I'm only year 9
The student's observations provide evidence that they had indeed produced calcium oxide by heating limestone. Here's why:
To begin with, the student crushed and heated limestone, which is primarily composed of calcium carbonate. When calcium carbonate is heated, it undergoes a chemical reaction called thermal decomposition. This reaction releases carbon dioxide gas and leaves behind calcium oxide.
By adding water to the heated limestone, the student facilitated a process called slaking. In slaking, calcium oxide reacts with water to form calcium hydroxide. This reaction is exothermic, meaning it releases heat. Therefore, when the water was added to the mixture, it caused the solution to become hot.
Next, the student cooled the mixture and filtered it. Filtering is a common technique used to separate solids from liquids. In this case, the white solid left in the filter paper was the calcium oxide obtained from the thermal decomposition of limestone. The colorless solution obtained through filtration likely contained calcium hydroxide.
To further confirm the presence of calcium ions in the solution, the student added universal indicator, which changes color based on the pH of the solution. When the universal indicator turned purple, it indicated the presence of a strongly basic solution. Calcium hydroxide is an alkaline compound and is known to produce a strongly basic solution, which would explain the color change observed.
Overall, the student's observations of a hot mixture, the presence of a white solid (calcium oxide) in the filter paper, and the purple color obtained with universal indicator all suggest that the student successfully produced calcium oxide by heating limestone.