4. Lead dioxide gives off a gas when heated. The gas relights a glowing splint. Give the name of this gas.
5. Hydrated cobalt chloride are dark red crystals. Give twoobservations you would make (what you would see) when these crystals are heated.
4. What are the properties of oxygen?
5. Doesn't this form a pattern with the answers to your previous questions?
To find the answer to question 4, you can utilize your knowledge about lead dioxide and gases that relight a glowing splint. Let's break down the process step by step:
1. Identify lead dioxide: Lead dioxide is a chemical compound that consists of lead and oxygen. Its chemical formula is PbO2.
2. Understand the reaction: When lead dioxide is heated, it undergoes a decomposition reaction, resulting in the release of oxygen gas (O2).
3. Recall the properties of oxygen gas: Oxygen gas is known to support combustion, meaning it helps fuel the burning process. It reacts exothermically (releasing heat) with flammable materials.
Therefore, the gas released when lead dioxide is heated and relights a glowing splint is oxygen gas (O2).
Moving on to question 5, we can determine the observations one might make when heated hydrated cobalt chloride crystals based on our knowledge of the compound. Here's how to approach it:
1. Identify hydrated cobalt chloride: Hydrated cobalt chloride is a compound that contains cobalt, chlorine, and water molecules. Its chemical formula is CoCl2.nH2O.
2. Understand the behavior of hydrated compounds when heated: When hydrated compounds are heated, the water molecules incorporated within the crystal structure are typically driven off as steam or vapor due to the applied heat.
Based on this information, here are two possible observations (what you would see) when heated hydrated cobalt chloride crystals:
1. Color change: The initially dark red crystals would gradually change color and become paler or turn blue. This color change occurs as a result of the water molecules being removed from the crystal structure.
2. Steam or vapor production: As the water molecules are driven off, you may observe the release of steam or vapor, indicating the presence of water being evaporated from the compound.
By following these steps, you can determine the name of the gas released when heating lead dioxide and identify two observations when heating hydrated cobalt chloride crystals.