Question

distinguishing mixtures from pure substances through physical properties read the descriptions below of two substances and an experiment on each. decide whether the result of the experiment tells you the substance is a pure substance or a mixture, if you can. sample a is 100 ml of a clear liquid. the density of the liquid is measured, and turns out to be 0.77 g/ml. the liquid is then cooled in the refrigerator. at 10.0 °c crystals begin to appear. the temperature of the liquid remains at 10.0 °c until all the liquid has crystallized. after all the liquid is frozen, the temperature starts to fall again, eventually reaching 6.2 °c. sample b is a solid yellow cube with a total mass of 50.0 g. the cube is put into a beaker filled with 250 ml of water. the cube collapses into a small pile of orange powder at the bottom of the beaker. when this powder is filtered out, dried and weighed, it has a total mass of 29.9 g. if the experiment is repeated with 500 ml of water, the powder thats left over has a mass of 10.0 g. is sample a made from a pure substance or a mixture? if the description of the substance and the outcome of the experiment isnt enough to decide, choose \cant decide.\ pure substance mixture (cant decide) is sample b made from a pure substance or a mixture? if the description of the substance and the outcome of the experiment isnt enough to decide, choose \cant decide.\ pure substance mixture (cant decide)

Explanation:

Step1: Analyze Sample A

Pure substances have a definite melting - freezing point. Sample A has a constant temperature during crystallization (at 10.0 °C), which is a characteristic of a pure substance.

Step2: Analyze Sample B

The mass of the residue changes with the volume of water used. This indicates that different components of the substance have different solubilities in water, which is a sign of a mixture.

Answer:

Is sample A made from a pure substance or a mixture? pure substance
Is sample B made from a pure substance or a mixture? mixture