Module 4: The Wonder of Water

Question 1

electrolysis

Answer 1

using electricity to break a molecule down into its constituent elements

Question 2

what are the constituent elements of water? (H2O)

Answer 2

hydrogen and oxygen

Question 3

polar molecule

Answer 3

a molecule that has slight positive and negative charges due to an imbalance in the way electrons are shared

Question 4

non polar molecule

Answer 4

has no net electrical charge

Question 5

solvent

Answer 5

a liquid substance capable of dissolving other substances

Question 6

solute

Answer 6

a substance that is dissolved in a solvent

Question 7

hydrogen bond

Answer 7

a weak bond that is established between the hydrogens on one water molecule and the oxygens on another molecule

Question 8

what is the difference between a hydrogen bond and a chemical bond?

Answer 8

hydrogen bonds link molecules together; chemical bonds link atoms together to form molecules

Question 9

cohesion

Answer 9

the phenomenon that occurs when individual molecules are so strongly attracted to each other that they tend to stay together, even when exposed to tension

Question 10

hard water

Answer 10

water that has certain dissolved ions in it, predominately calcium ions

Question 11

what type of substances can water dissolve?

Answer 11

polar molecules and ionic molecules

Question 12

What is the chemical formula for water?

Answer 12

h2o

Question 13

The chemical formula for baking soda is NaHCO3. How many atoms make up one molecule of baking soda?

Answer 13

6

Question 14

Vinegar’s actiave ingredient is acetic acid, C2H4O2. How many of each atom is present in a molecule of acetic acid?

Answer 14

2 carbon atoms, 4 hydrogen atoms, 2 oxygen atoms

Question 15

a molecule of glucose contains six carbon atoms, twelve hydrogen atoms, and six oxygen atoms. What is the chemical formula of glucose?

Answer 15

C6H12O6

Question 16

Why is water liquid at room temperature, while other similar substances are gases at room temperature?

Answer 16

hydrogen bonding is the reason because it keeps the molecules close together

Question 17

Why are water molecules polar?

Answer 17

because both the oxygen and hydrogen atoms are fighting over the electrons that they are supposed to be sharing. Oxygen can pull on the electrons harder, so it gets more than its fair share of electrons, making it slightly negative. Since the hydrogen atoms get less than their fair share of electrons, they end up slightly positive.