Question

1. Water, ethanol and hexane are known solvents in a liquid state. When heated, the rising temperature changes the state from liquid to gas. Is this a chemical or physical change? Can you arrange from lowest to highest the ease of boiling? (5 pts 2. If you have a mixture of hexane and water in a beaker. Which is the top layer? Explain (5 pts) 3. The length of a ballpoint pen was recorded by the students as: (5 pts) 14.30 cm 14.33 cm 14.34 cm There is always introduces uncertainty in measurements. a. Circle the digit that is considered estimated. b. How many figures are certain?

Answer 1

Answer 1. Change in state is a physical change. So, change from liquid to gas of water, ethanol and hexane is physical change.

Hexane has 68^oC, ethanol has 78^oC and water has 100^oC as their boiling point. So the lowest to highest ease order is water, ethanol and hexane.

Answer 2. Hexane will be in top layer as it is lighter than water (since density of hexane is 0.66g/ml and 1g/ml that of water).