Mandala Chemistry

A water molecule has the chemical formula H2O. This means that the water molecule is made up of

• Two hydrogen atoms and one oxygen atom

• Two oxygen atoms and one hydrogen atom

• Two hydrogen atoms and two oxygen atoms

• Two molecules of water

The atoms in a water molecule are held together by covalent bonds. This means that the bonded atoms

• Two hydrogen atoms and one oxygen atom

• Two oxygen atoms and one hydrogen atom

• Two hydrogen atoms and two oxygen atoms

• Two molecules of water

The water molecule is a polar molecule. A water molecule is polar because

• The electrons are shared equally

• Oxygen has a stronger attraction for electrons than hydrogen

• It is very cold

• Hydrogen atoms have a stronger attraction for electrons than oxygen

The water molecule is ....

• Slightly negative near the hydrogen atoms and slightly positive near the oxygen atom

• Slightly positive in all areas of the molecule

• Slightly negative near the oxygen atom and slightly positive near the hydrogen atoms

• The same charge in all areas of the molecule

Water molecules are attracted to each other because....

• They are all positively charged

• Each water molecule has the same number of protons as electrons

• The positive area of one water molecule is attracted to the negative area of another

• All water molecules are neutral

If liquid A is more polar than liquid B, you might expect

• Liquid A to evaporate faster than liquid B

• Liquid A to evaporate more slowly than liquid B

• Liquid A and liquid B to evaporate at the same rate

• Liquid B to be colored

A paper clip can stay on the surface of a sample of water because of water’s strong surface tension. Water’s surface tension is mostly a result of

• Water’s temperature

• The motion of water molecules

• The attraction of water molecules

• The impurities in the water

Sodium chloride is made up of sodium ions and chloride ions which bond together in a salt crystal because

• They have the same charge

• They are the same size

• One is positive and one is negative so they attract

• They both have protons and electrons

Water is able to dissolve sodium chloride because

• The polar areas of water molecules attract the oppositely charged ions of sodium chloride

• The shape of the water molecules pushes the sodium and chloride ions apart

• The oxygen in the water molecules reacts with the sodium and chloride ions

• Water molecules and sodium chloride are covalently bonded

Water cannot dissolve all substances that are made from ionic bonds. This is probably because

• Some water molecules are not as strong as others

• Water needs to be stirred to dissolve all ionic substances

• Some ionic bonds are too strong for the attractions of water molecules to pull them apart

• Water needs to be heated to dissolve all ionic substances