To determine which substance is most likely a mixture based on the given descriptions, we need to analyze each description carefully.
1. Substance P: Formed by boiling pure water.
- Pure water, when boiled, remains a pure substance. There is no combination or mixing with other substances. Thus, substance P is a pure substance.
2. Substance Q: Formed by combining three hydrogen atoms to every nitrogen atom.
- This description indicates the formation of a compound (specifically, ammonia, NH₃), as it involves a chemical combination of hydrogen and nitrogen atoms. Therefore, substance Q is clearly a compound.
3. Substance R: Formed by adding 5 grams of sugar to 1 liter of water.
- Here, sugar is dissolved in water. This creates a mixture, as both sugar and water retain their chemical properties while being physically combined. Such a mixture is called a solution where the sugar (solute) dissolves in the water (solvent).
4. Substance S: Formed by compressing carbon under high pressure.
- Compressing carbon under high pressure forms a different allotrope of carbon, like diamond, but it remains an element since it is composed only of carbon atoms. Thus, substance S is an element.
Based on the analysis, it is clear that substance R, formed by adding 5 grams of sugar to 1 liter of water, is the mixture.
Therefore, the substance most likely to be a mixture is:
- R
