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The smallest possible piece of the compound hydrogen peroxide contains two hydrogen atoms and two oxygen atoms. Write the chemical formula for hydrogen peroxide, with hydrogen first.

The smallest possible piece of the sugar glucose has twice as many hydrogen atoms as oxygen atoms or carbon atoms. Given that glucose has six carbon atoms, write its chemical formula with carbon first, then hydrogen, then oxygen.

The air you breathe is made up mostly of nitrogen gas, \(\mathrm{N}_{2}\). (a) What can you say about the smallest possible piece of nitrogen gas? (b) Is nitrogen gas a compound? Explain.

What are the three most common states of matter?

What is the name of the process by which matter changes directly from the solid state to the gas state?

Propane has a boiling point below room temperature, and hexane has a boiling point above room temperature. In what physical state would you expect to find each substance at room temperature (which is usually about \(\left.20{ }^{\circ} \mathrm{C}\right) ?\)

At normal atmospheric pressure, the freezing point of ethanol is \(-114^{\circ} \mathrm{C}\) and its boiling point is \(78.4{ }^{\circ} \mathrm{C}\). What is the melting point of ethanol?

Solid mothballs work by filling a closet with a chemical vapor that is toxic to moths, and the balls shrink and disappear slowly with time. What is going on?

What are the melting point and boiling point of water in degrees Celsius and degrees Fahrenheit (at normal atmospheric pressure)?

Water, \(\mathrm{H}_{2} \mathrm{O}\), is a harmless liquid, but hydrogen peroxide, \(\mathrm{H}_{2} \mathrm{O}_{2}\), is a poison. How is this possible, given that both are compounds of hydrogen and oxygen?