A science teacher conducts an experiment to compare the nature of oxides formed by a metal and a non-metal.
The teacher performs the following steps:
- A magnesium ribbon is cleaned and burned in air. A white powder (Substance P) is obtained.
- A small amount of sulfur is heated. It burns with a blue flame, producing a gas (Substance Q).
- Substance P is dissolved in water and tested with red and blue litmus papers.
- Substance Q is dissolved in water and tested with red and blue litmus papers.
The students record the following observations.
| Substance | Observation in Water | Effect on Litmus Paper |
| P | Forms a solution | Red litmus turns blue |
| Q | Forms a solution | Blue litmus turns red |
The teacher asks the students to analyse the observations and get conclusions.
Answer variants:
acidic
magnesium oxide
red
basic
sulfur dioxide
blue
green
magnesium dioxide
1. Find Substance P and Substance Q
Substance P is .
Substance Q is .
2. What conclusion can be drawn about the products formed when metals and non-metals burn in oxygen?
Metals generally form oxides, whereas non-metals generally form oxides. The activity demonstrates that behaves as a base and behaves as an acid. Thus, the nature of the oxide depends on whether it is formed from a metal or a non-metal.
3. What is the nature of the two substances when dissolved in water? How do you know?
Substance P forms a solution.
Substance Q forms a solution.
When Substance P was tested with litmus paper, it changed litmus paper to . This is the characteristic property of a basic solution.
The solution prepared from Substance Q changed litmus paper to . This change indicates that the solution is acidic.