Question

understand concepts
use the data table to answer questions 63–66.

substance	color	melting point (°c)	boiling point (°c)
chlorine	green-yellow	−101	−34
ethanol	colorless	−117	78
mercury	silvery-white	−39	357
neon	colorless	−249	−246
sulfur	yellow	115	445
water	colorless	0	100

1. which colorless substance is a liquid at −30°c?
2. which colorless substance is a gas at 60°c?
3. which substance is a solid at 7°c?

*66. as the temperature rises, which solid will melt before mercury boils?

Explanation:

Question 63

Step1: Identify colorless substances

Colorless substances: Ethanol, Neon, Water.

Step2: Check state at -30°C

• Ethanol: Melting point -117°C, Boiling point 78°C. At -30°C, between melting and boiling, so liquid.
• Neon: Melting -249°C, Boiling -246°C. At -30°C, above boiling, so gas.
• Water: Melting 0°C. At -30°C, below melting, so solid.

Step1: Identify colorless substances

Colorless substances: Ethanol, Neon, Water.

Step2: Check state at 60°C

• Ethanol: Boiling point 78°C. At 60°C, below boiling, so liquid.
• Neon: Boiling point -246°C. At 60°C, above boiling, so gas.
• Water: Boiling point 100°C. At 60°C, below boiling, so liquid.

Step1: Check melting/boiling points

• Bromine: Melting -7°C. At 7°C, above melting, liquid.
• Chlorine: Boiling -34°C. At 7°C, above boiling, gas.
• Ethanol: Melting -117°C. At 7°C, liquid.
• Mercury: Melting -39°C. At 7°C, liquid.
• Neon: Boiling -246°C. At 7°C, gas.
• Sulfur: Melting 115°C. At 7°C, below melting, solid.
• Water: Melting 0°C. At 7°C, liquid.

Answer:

Ethanol

Question 64