Question

iodine crystals do not dissolve in water. this is because

• iodine crystals are polar and water is non - polar
• iodine crystals are polar and water is polar
• iodine crystals are non - polar and water is polar
• iodine crystals are non - polar and water is non - polar

what property of water causes water to form a curved shape on the penny?

• density
• heat capacity
• polarity
• melting point

how do water molecules attach to other water molecules?

• covalent bonds
• ionic bonds
• water - water bonds
• hydrogen bonds

why do oil and water separate after being mixed?

• water is polar and oil is non - polar. non - polar molecules are not attracted to polar molecules.
• water is polar and oil is non - polar. the attraction between polar molecules and nonpolar molecules are not strong enough to mix.
• water and oil are both polar. polar molecules are not strongly attracted to each other.
• water is and oil are both non - polar. non - polar molecules are not strongly attracted to each other

Explanation:

First Question (Iodine dissolving in water)

The principle "like dissolves like" applies. Iodine (\(I_2\)) is a diatomic molecule with a non - polar covalent bond, so iodine crystals are non - polar. Water (\(H_2O\)) has a polar covalent bond due to the electronegativity difference between hydrogen and oxygen, making water polar. Non - polar substances do not dissolve well in polar solvents. So the correct option is the one stating iodine crystals are non - polar and water is polar.

The curved shape of water on a penny is due to surface tension, which is related to the polarity of water molecules. Water molecules are polar, and the cohesive forces between them (due to polarity - related hydrogen bonding) create surface tension. Density relates to mass per unit volume, heat capacity to heat absorption, and melting point to the temperature of phase change, none of which cause the curved shape.

Water molecules are polar, with a partially positive hydrogen and a partially negative oxygen. The attraction between the partially positive hydrogen of one water molecule and the partially negative oxygen of another water molecule is a hydrogen bond. Covalent bonds are within a water molecule, ionic bonds involve ions, and "water - water bonds" is not a recognized bond type.

Answer:

C. iodine crystals are non - polar and water is polar (assuming the options are labeled A, B, C, D in order)

Second Question (Water forming a curved shape on a penny)