In a(n) reaction, the products are at a higher energy level than are the reactants.
select one:
a. endothermic
b. activation
c. exothermic
d. catalytic

In an endothermic reaction, the products are at a higher energy level than are the reactants.

Explanation:

ΔH = E products - E reactants.

So, for endothermic reactions, the products are at a higher energy level than are the reactants.

Kindly see the attached image.

a sequence is a function whose domain is the set of natural numbers.

natural numbers are all the negative and positive integers

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally