Which of these is not an element? 1. On heating it gives off a gas and

1.	Which of these is not an element? 1. On heating it gives off a gas and leaves residue. 2. It burns in air to form carbon dioxide and water. 3. It changes into solid at 273 K and to gas at 373 K. I don't know about elements so can you please explain the answer?
Answer» Which of these is not an element? 1. On heating it gives off a gas and leaves residue. 2. It burns in air to form carbon dioxide and water. 3. It changes into solid at 273 K and to gas at 373 K. I don't know about elements so can you please explain the answer?

Which of these is not an element? 1. On heating it gives off a gas and leaves residue. 2. It burns in air to form carbon dioxide and water. 3. It changes into solid at 273 K and to gas at 373 K. I don't know about elements so can you please explain the answer?

Answer»

Which of these is not an element?

1. On heating it gives off a gas and leaves residue.

2. It burns in air to form carbon dioxide and water.

3. It changes into solid at 273 K and to gas at 373 K.

I don't know about elements so can you please explain the answer?