REDOX REACTIONS Flashcards
Define oxidation. (1)
Oxidation refers to the loss of electrons by a substance, leading to an increase in its oxidation state. It often involves the addition of oxygen or loss of hydrogen.
Define a redox reaction. (1)
where one substance loses electrons (oxidation) while another gains electrons (reduction).
What is an oxidation state? (1)
indicate the number of electrons that an atom has gained or lost to form a chemical bond.
What are oxidising agents? (1)
Substances that cause other substances to undergo oxidation are called oxidizing agents. They gain electrons themselves during the reaction.
What are some examples of oxidation reactions? (3)
-Combustion reactions
-corrosion of metals
-biological oxidation (cellular respiration)
What is the oxidation state of a compound? (1)
Always zero
What is the oxidation state of oxygen? (1)
-2
What are the exceptions to oxygens oxidation state? (1)
In peroxides such as H2O2 oxidation state is -1
What is the oxidation state of hydrogen? (1)
+1
What are the exceptions to hydrogens oxidation state? (1)
In metal hydrides such as NaH, oxidation state is -1
Define reduction. (1)
Reduction refers to the gain of electrons by a substance, leading to a decrease in its oxidation state.
What is meant by electron transfer? (1)
In a reduction reaction, electrons are gained by a substance. This can occur through the direct transfer of electrons from another substance or through the gain of electrons from an external source.
What are reducing agents? (1)
Substances that cause other substances to undergo reduction are called reducing agents. They lose electrons themselves during the reaction.
How does reduction alter oxidation states? (1)
Reduction leads to a decrease in the oxidation state of a substance.
What are hydrogenation reactions? (1)
Reduction reactions often involve the addition of hydrogen atoms to unsaturated compounds, converting them into saturated compounds.
How are reduction reactions important biologically? (1)
Reduction plays a crucial role in biological processes such as photosynthesis, where carbon dioxide is reduced to glucose in plants using energy from sunlight.
Define disproportionation. (1)
Disproportionation is a type of redox reaction where the same element undergoes both oxidation and reduction within the same chemical reaction.
What reactions are usually disproportionation? (2)
often involve an element in an intermediate oxidation state being converted to two different oxidation states. One species of the element is oxidized, while another is reduced.
Why are disproportionation reactions important? (1)
are important in various industrial processes, such as the production of bleach and in biological systems, such as the decomposition of hydrogen peroxide in cells.
What are some common oxidising agents? (3)
H2SO4, Al3+ and Cl2
What are some common reducing agents? (4)
Na, O2-, I2 and H2O32-
