Types of mixtureIB MYP Chemistry: Mind map

Exam questions on Types of mixture

1. A student looks up how much of two solids dissolves in 100 g of water to make a saturated solution. Potassium nitrate: 32 g at 20 °C, 64 g at 40 °C, 109 g at 60 °C and 169 g at 80 °C. Sodium chloride: 36 g at 20 °C, 36 g at 40 °C, 37 g at 60 °C and 38 g at 80 °C.
   Describe how the effect of temperature on the solubility of sodium chloride differs from its effect on potassium nitrate.2 marks
2. A food technologist classifies four products. Muddy river water has soil particles that can be seen and settle to the bottom after an hour. Sweet tea is clear, with the sugar particles too small to see. Mayonnaise has tiny droplets of oil spread through a water-based liquid and stays evenly mixed. A bronze coin is made by melting copper and tin together and letting the liquid solidify.
   Explain why bronze is classed as an alloy and as a mixture.2 marks
3. A student investigates how temperature affects how much potassium nitrate dissolves. She warms 20 g of water to each chosen temperature in a water bath, adds potassium nitrate in small portions while stirring, and records the total mass added when some solid will no longer dissolve. The total masses dissolved in 20 g of water were: 6.4 g at 20 °C, 12.8 g at 40 °C, 21.8 g at 60 °C and 33.8 g at 80 °C.
   Describe the pattern in the results, using data from the investigation.3 marks