Question

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 liquid is heated in a flask until it boils. the vapor that rises off the boiling liquid is collected for 10 minutes and cooled until it condenses into a separate beaker. the density of the liquid that remains in the flask is then measured, and turns out to be 1.04 g/ml. the density of the liquid that boiled off turns out to be 0.77 g/ml. sample b is 100. g of a coarse grey powder with a faint unpleasant smell. 15. g of the powder are dissolved in ethanol. 0.5 mg of the resulting black solution is carefully dropped onto a thick sheet of paper laid flat in a tray. after 30 minutes the initial round black stain has spread out and faded in color to a deep purple. 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

In sample A, when heated, the liquid separates into two parts with different densities. Pure substances have consistent physical properties throughout, and different densities of the boiled - off part and the remaining part indicate different components. So it is a mixture.

Step2: Analyze sample B

In sample B, when a solution of the powder in ethanol is dropped on paper, the stain spreads and changes color. This indicates that there are multiple components in the powder that separate and move at different rates, which is characteristic of a mixture.

Answer:

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