Physical Separation Techniques for Mixtures

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5 questions from this lesson’s quiz. Start the lesson to answer them and see the right answers.

1. 1. A mixture of common salt (NaCl) and ammonium chloride (NH_4Cl) is heated gently in an evaporating dish covered with an inverted funnel. Which separation technique is being used, and why does it work?

   • A. Sublimation, because ammonium chloride changes directly from solid to gas while salt does not
   • B. Filtration, because salt is insoluble and ammonium chloride is soluble
   • C. Decantation, because ammonium chloride is denser than salt
   • D. Chromatography, because the two solids move at different speeds on paper

2. 2. Cooking oil and brine (salty water) are shaken together and left to stand. Which method separates them, and which property makes it possible?

   • A. Simple distillation, because they have different melting points
   • B. Using a separating funnel, because they are immiscible and have different densities
   • C. Using a magnet, because brine is magnetic
   • D. Filtration, because oil is an insoluble solid

3. 3. In the fractional distillation of liquid air, nitrogen (boiling point -196 °C) boils off before oxygen (boiling point -183 °C). Why?

   • A. Nitrogen has a higher boiling point than oxygen
   • B. Nitrogen has a lower boiling point than oxygen, so it vaporises first as the temperature rises
   • C. Nitrogen is magnetic and is pulled out of the column
   • D. Nitrogen is insoluble in liquid oxygen and is filtered out

4. 4. Pupils in Kilifi want to get both clean water and salt from muddy seawater. Which order of methods is correct?

   • A. Simple distillation first, then filtration of the vapour
   • B. Use a magnet, then a separating funnel
   • C. Filter out the mud, then distil the filtrate to collect water and leave salt
   • D. Sublimation of the mud, then chromatography of the salt

5. 5. In filtration, what name is given to the insoluble solid that stays on the filter paper?

   Type your answer in the lesson.

More in Introduction to Integrated Science

• ▸Derived SI Quantities
• ▸Laboratory Apparatus Heating and Mass Measurement
• ▸Optical Instruments and Volumetric Glassware
• ▸Classification of Mixtures and Purity Determination
• ▸Community Service Learning Water Purification Project
• ▸Acids, Bases, and Natural Indicators
• ▸Acids, Bases and the pH Scale
• ▸Introduction to Laboratory Safety and Rules

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