A redox reaction is a reaction that involves both reduction and oxidation, it involves a reducing agent which looses electrons and undergoes oxidation and an oxidizing agent that gains electrons (reduction). I believe the following are true about redox reactions; Electrons move from one substance to another, One atom gains electrons and one looses electrons.
Answer: A, C, E
Explanation: PLATO. all testable questions.
Answer: a) 
: Decomposition
b) 
: double displacement
c) 
: Synthesis (Combination)
d) 
: redox
Explanation:
Decomposition is a type of chemical reaction in which one reactant gives two or more than two products.
A double displacement reaction is one in which exchange of ions take place.
Synthesis reaction is a chemical reaction in which two reactants are combining to form one product.
Redox reaction is a type of chemical reaction in which oxidation and reduction takes place in one single reaction. The oxidation number of one element increases and the oxidation number of other element decreases.
Answer: -112200J
Explanation:
The amount of heat (Q) released from an heated substance depends on its Mass (M), specific heat capacity (C) and change in temperature (Φ)
Thus, Q = MCΦ
Since,
Q = ?
Mass of water vapour = 30.0g
C = 187 J/ G°C
Φ = (Final temperature - Initial temperature)
= 100°C - 120°C = -20°C
Then apply the formula, Q = MCΦ
Q = 30.0g x 187 J/ G°C x -20°C
Q = -112200J (The negative sign does indicates that heat was released to the surroundings)
Thus, -112200 joules of heat is released when cooling the superheated vapour.
