Chapter 4- The chemistry of life (3) Flashcards
What is a hydrogen bond?
It is an attraction between a H atom carrying a partial positive charge and an electronegative atom.
When do hydrogen bonds form?
It forms when hydrogen is already covalently bonded to either nitrogen or oxygen.
Is hydrogen bonds weak?
Yes
When do chemical reactions occur?
When electrons are gained or lost
When chemical bonds are altered
What are the types of chemical reactions?
1- Synthesis- where small particles are bonded together to form larger, complex molecules. This is an anabolic reaction
2- Decomposition reaction- where bonds are broken down in larger molecules, resulting in smaller, less complex molecules. This is a catabolic reaction
3- Exchange/ displacement reaction- where bonds are both made and broken
What type of reaction is an oxidation- reduction reaction?
Both a decomposition reaction and an exchange reaction
If one reactant loses electrons and another gains electrons what happens and what do they become?
If one reactant loses electrons, it becomes electron donor and it is oxidised
If one reactant gains electrons, it becomes an electron acceptor and it is reduced.
Can an oxidation-reduction reaction be an ionic reaction or covalent bonding?
Yes
What is an example of an oxidation- reduction reaction?
Cellular respiration. Glucose is oxidised to carbon dioxide as it loses a hydrogen. Oxygen is reduced to water as it gains a hydrogen.
What do chemical reactions do?
1- Release energy- exergonic reaction- catabolic or oxidative reactions
2- Absorb energy- endergonic reaction- anabolic or reduction reaction
Why do exergonic and endergonic tend to go hand in hand?
Because we do not want to lose energy from the system.
What are the external factors that influence chemical reaction rates?
1- Temperature
2- Concentration
3- Enzymes
What is the main difference between organic and inorganic compounds?
Organic compounds contain carbon
Inorganic compounds don’t contain carbon- Examples include water, salts, acids
How are all organic compounds bonded?
They are covalently bonded
What are the properties of water?
Has a high heat capacity- able to store of a lot of heat between the molecules.
Has a high heat of vaporisation- this means that a lot of energy is needed to turn water into a gas.
Essential reactant in many reactions
Water is polar- when one end of the molecule/ substance is slightly positive and the other end is slightly negative.
