Hydrogen (H) was first, followed by helium (He).
Hello!
The reaction that the graph represents is
A. Exothermic because Hrxn=-167 kJTo calculate Hrxn we apply the following equation:

Looking at the graph, and at the result of the calculations, we can see that the enthalpy of the products is
lower than the enthalpy of the reagents, because the sign is negative. That means that the reaction
releases energy in the form of heat and that the reaction is
exothermic.
Have a nice day!
When energy transforms into mass, the amount of energy does not remain the same. When mass transforms into energy, the amount of energy also does not remain the same. However, the amount of matter and energy remains the same. ... You would weigh much less on the Moon because it is only about one-sixth the mass of Earth. So the answer is D
Answer : The atom with the same number of neutrons as
is, 
Explanation :
- The given atom is,

Atomic mass number = 12
Atomic number = 6
Atomic number = Number of protons = Number of electrons = 6
Number of neutrons = Atomic mass number - Atomic number = 12 - 6 = 6
Now we have to determine the number of neutrons in the given options.
- In atom,

Atomic mass number = 9
Atomic number = 4
Atomic number = Number of protons = Number of electrons = 4
Number of neutrons = Atomic mass number - Atomic number = 9 - 4 = 5
- In atom,

Atomic mass number = 11
Atomic number = 5
Atomic number = Number of protons = Number of electrons = 5
Number of neutrons = Atomic mass number - Atomic number = 11 - 5 = 6
- In atom,

Atomic mass number = 13
Atomic number = 6
Atomic number = Number of protons = Number of electrons = 6
Number of neutrons = Atomic mass number - Atomic number = 13 - 6 = 7
- In atom,

Atomic mass number = 14
Atomic number = 7
Atomic number = Number of protons = Number of electrons = 7
Number of neutrons = Atomic mass number - Atomic number = 14 - 7 = 7
Therefore, the atom with the same number of neutrons as
is, 
Answer:
Does the Big Bang theory count?