2nd midterm review

Some students are asked to describe differences between gases and liquids. Three of their suggestions are:

(1) gas molecules are further apart;

(2) gas molecules are smaller;

(3) liquid molecules vibrate around fixed positions. Which suggestion(s) is/are correct?

• 1 only
• 2 only
• 3 only
• 1 and 3 only

When steam at 100 oC condenses to water at 25 oC, what happens to the water molecules?

• They move faster and closer together.
• They move faster and further apart.
• They move slower and closer together.
• They move slower and further apart.

How many electrons are shared between the atoms in a molecule of carbon dioxide?

(a)  

Which gas diffuses slowest?

• ethane

• carbon dioxide
• hydrogen
• argon

X and Y are isotopes of the same element, so the chemical properties of A and Y are similar.

• True
• FALSE

Which statement describes the attractive forces between covalent molecules?

• A. They are strong covalent bonds which hold molecules together.
• B. They are strong ionic bonds which hold molecules together.
• C. They are weak forces formed between covalently-bonded molecules.
• D. They are weak forces which hold ions together in a lattice.

Why is copper malleable?

• A. Its ions are attracted to the ‘sea of electrons’.
• B. Its ions are tightly packed together.
• C. Its ions repel each other.
• D. Its layers of ions can slide over each other.

The relative atomic mass of fluorine is 19. What is the mass of 2 mol of fluorine gas?

• 19
• 38
• 76
• 9.5

A compound with the formula XCl2 has a relative formula mass of 111. What is the name of X?

(a)  

A sample containing 0.0800 mol of potassium carbonate is added to a solution containing 0.100 mol of hydrochloric acid. Which volume of carbon dioxide is produced, measured at room temperature and pressure?

• A. 0.96 dm3
• B. 1.20 dm3
• C. 1.92 dm3
• D. 2.40 dm3