Tutor profile: Bea A.
Distinguish between endothermic and exothermic processes in terms of enthalpy changes.
Enthalpy is the heat content of a substance. An ENDOthermic process absorbs heat (ENdo/IN) and an EXOthermic process releases heat (EXO/EXITS). With all this information it is easy to remember that enthalpy increases in endothermic reactions and decreases in exothermic ones.
Explain the cohesive and adhesive property of water.
Cohesion is when alike molecules attract each other. Adhesion is when unlike molecules attract each other. Knowing this, when two water molecules attract (cohesion) bonds form between these two molecules. This is called hydrogen bonding. These bonds are temporary (which also explains why water forms into droplets when split) and create a surface ‘tension’. When water molecules are attracted to other types of molecules for example cellulose (the component of plant cell walls) it allows water to be pulled up as column. Cohesion moves water up and adhesion prevents the column to slide down.
Why don't antibiotics work on viruses?
The central idea is that antibiotics work by interfering with the metabolic processes of organisms. Viruses lack their own metabolism, they have to use the chemical processes of the host cell that they have infected in order to survive. They cannot reproduce on their own and cannot perform protein synthesis, transcription and other metabolic functions. Due to this, antibiotics have no effect on viruses.
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