Answer:
<h2>Krypton is a halogen, so it should be kept secret because it is so reactive and toxic. Krypton is a noble gas, so it was difficult for chemists to find it, as though it was a secret.</h2>
Explanation:
<h2>
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The potential energy stored in the form of heat is called as enthalpy of a system. The reactions in which a system absorbs heat, are called as endothermic reactions. The ones in which a system releases heat, are called as exothermic reactions
I am answering A question
Answer:
1(a) N = 3
(b) N = 0
(c) N = 5
(d) N = -2
(2) Molecular formula for benzene is C6H6
Explanation:
1(a) N02 1-
N + (2×-2) = -1
N-4 = -1
N = -1+4 = 3
(b) N2
2(N) = 0
N = 0/2 = 0
(c) NO2Cl
N + ( 2×-2) + (-1) = 0
N - 4 - 1 = 0
N - 5 = 0
N = 0+5 = 5
(d) N2H4
2(N) + (4×1) = 0
2N + 4 = 0
2N = 0 - 4 = -4
N = -4/2 = -2
(2) Molcular mass of benzene = 78g/mole = (6×12g of carbon) + (6×1g of hydrogen) = 72+6 = 78g/mole
Therefore, molecular formula for benzene is C6H6