Answer:
B is False
Explanation:
In physical chemistry we always look from system's perspective, so if we heat something ΔH is positive and if the system gives heat out then ΔH is negative.
A. We have to give energy to benzene to evaporate it. Statement true.
B. If heat is absorbed then the enthalpy must be positive.
C. The heat is absorbed then ΔH is positive.
D. Usually for burning heat is exposed from system. So enthalpy is negative.
E. Obvious
Answer:
penicillin could protect mice against infection from deadly Streptococci.
Explanation:
Answer:
ii.
Explanation:
Isoelectric species are the species which have same number of electrons.
From the given options:-
are the isoelectric species.
All the three species have same number of electrons which is equal to 6.
Carbon has 6 electrons.
has 6 electrons.
has 6 electrons.
Explanation:
Percentage ethylene by weight = 57%
Percentage propylene by weight = 43%
Suppose in 100 grams of polymer:
Mass of ethylene = 57 g
Mass of propylene = 43 g
Moles of ethylene =
Moles of propylene =
1 mole = molecules/ atoms
Units of ethylene =
Units of propylene =
a) Fraction of ethylene units:
b ) Fraction of propylene units: