Hots Questions : Think and answer.
- A bottle contains either salt to chalk. How will you find out what it has, without tastion it?
- Think and write how you will separate a mixture of water, sand, salt and iron filings. You may have to use a method not given in the chapter to separate sand and iron filings. Think -- which property of iron can be used for this?
- A mixture of salt and sugar is prepared by grinding then together. Do the molecules of the salt and sugar undergo any change?
- A Saturated solution of sugar in water is prepared. The temperature of water is lowered by 50C. Will the solution continue to be saturated ? Give reasons.
- Sea water has salt dissolved in it. You know that pure water can be obtained from sea water by distillation. However, this method is not used to get drinking water from sea water. What do you think is the reason?
1. Take water and add to it. If it will dissolve in water, then it is salt and if it will not dissolve in water, then it is chalk.
2. To seperate iron fillings,usemagnet to seperate it. Sand, salt and water is left. Seperate sand by sedimentation and decantation. Salt and water is left. Seperate salt from water by evaporation and condensation.
4. Yes, temperature doesn't matter here.
5. Because by distillation all the impurities cannot be seperated.
- Take the content and stirr it in water, if it dissolves it is salt and if it settles down as sediment, it is chalk.
- 1st = For iron filings - magnetic separation, left sand, salt and water. 2nd = For sand - sedementation and decantation, left salt, water. 3rd = For water and salt - distillation.
- Yes, temparature does not matter here.
- we use distillation.