Molecules Flashcards
What is a polar molecule?
A molecule with slight charge
What is a non-polar molecule?
A molecule with zero charge
What is a polar covelent bond and how is it formed?
Slightly positively charged ions attract to slightly negatively charged ions and share electrons, this forms the bond and happens due to a force of attraction.
What are the 7 properties of water?
- Adhesion
- Cohesion
- High specific heat capacity
- High heat of vaporization
- High heat of Fusion
- Versatile solvent
- Higher density as a liquid than as a solid
What is cohesion?
When two water molecules attract to each other and create hydrogen bonds, this happens due to O- and H+ attracting
What is adhesion?
When a molecule of water attracts to an other molecule and creates a hydrogen bond, this happens due to a polar end of the water attracting the opposing polar end of the other ion
How is cohesion and adhesion used?
- Surface tension, water does not break at the surface due to hydrogen bonds, this allows some insects to walk on the water,
- Carrying water and mineral ions up xylems, the water attaches to each other (cohesion), and pulls itself up the wall of the xylem (adhesion)
- Capillary action, adhesion in a narrow tube, this cause a meniscus which can me measured for volume
What is Specific heat capacity?
The amount of energy it takes to raise 1 gram by 1°C
Why is high specific heat capacity good in water?
- Temperature does not change quickly*
- This means we keep a stable body temperature as out body has time to make adjustments to cool down or heat up depending on a changing weather,
- Also means that life in water will have time to adapt to their change in environment as the weather gets hotter
What is a Versatile solvent?
Water has the capabilities of dissolving most solutes
Why is water being a versatile solvent beneficial?
- In plants, mineral ions dissolve in water and are carried up in the xylems to the rest of the plant
- In animals, water makes up a large proportion of our cells and can transport important nutrients.
What is Heat of vaporization?
The energy it takes to turn a liquid into a gas or gas to liquid/ change state
- In water: 540cal/g at 100°C
Why is a high heat of vaporization important?
- In order to cool down, our bodies use excess energy to evaporate sweat (predominantly water) on the surface of our skin, this energy is lost to the surroundings as the water vapor leaves our skin
Why does water have a higher density than ice?
When water freezes, the lattice structure it forms when it changes state has the water molecules spread further apart than when the water was a liquid. Since the water molecules are closer together as a liquid, its density is greater
Why is it important for some animals that water has a higher density than ice?
A layer of ice will float atop the body of water so the fish are free to live unfrozen underneath
What type of bonds form from water to water?
Hydrogen bonds
What type of bonds form between the OH+ and H- in water molecules?
Polar covalent bonds
What is a calorie?
The amount of energy it takes to raise 1 g of WATER by 1°C
What does hydrophobic mean?
When something is hydrophobic it is non-polar, so it does not attract to the polar water molecules
What does Hydrophilic mean?
When a molecule is hydrophilic it is polar, so it does attract to polar water molecules
What is electronegativity?
The attractive force that an atomic nucleus exerts on electrons.
If a molecule is electronegative it is charged
Where is another example of where hydrogen bonds are used?
Bonds between base pairs in a nucleotide
Why does water have a high specific heat capacity?
The energy emitted onto the water does not excite the molecules and cause them to move quicker, instead, the energy is used to attempt to break the hydrogen bonds between water molecules. So the water resists temperature change
What is a macromolecule?
larger molecules, also known as polymers.
- The polymers are made of monomers that bond together
- ‘Poly’ means many
- ‘Mer’ means unit
What are the 4 functional groups?
- Hydroxyl group (OH)
- Carboxyl group (COOH)
- Phosphate group (P)
- Amine Group (NH2)
What is a condensation reaction?
Removal of a water molecule when bonding two monomers together, creating a polymer with a hydrogen bond and a biproduct of water
What is a hydrolysis reaction?
The addition of water to a polymer, breaking it down back into its original monomers with the water distributed between the two monomers
What is another name for a condensation reaction?
A dehydration reaction
What is the functional group of Carbohydrates?
C:H:O (1:2:1)
What are examples of Carbohydrates?
- Glucose
- Starch
- Cellulose
- Ribose
- Lactose
What is the bond created in a Carbohydrate polymer?
Glycosidic bond
What is the function of Carbohydrates?
Fast energy, structure, identification
What is the Carbohydrate monomer called?
Monosaccharides
What is the chemical formula for the structure of a monosaccharide?
C{n}H{2n}O{n}
What is the differences between Ribose and Deoxyribose?
- In ribose there is a hydroxyl group at C2
- Ribose is single stranded so less stable
- Deoxyribose is double stranded so more stable
What are the similarities between Ribose and Deoxyribose?
- Both are pentoses/ 5 Carbon sugars
What is the structure of cellulose?
- Thick long chain, so very tough
- β glucose
What is cellulose used for?
The cell wall in plants