The average atomic mass of the element is the sum of the products of the percentage abundance of isotope and its mass number. Therefore, for atomic mass equal to 58.933, the most abundant isotope is cobalt-59. Thus, the answer is letter C.
Point of the graph because it’s the point
The symbol : 
<h3>Further explanation
</h3>
There are two components that accompany an element, the mass number and atomic number
Atoms are composed of 3 types of basic particles (subatomic particles): <em>protons, electrons, and neutrons
</em>
The Atomic Number (Z) indicates the number of protons and electrons in an atom of an element.
Atomic number = number of protons = number of electrons ⇒ neutral number
Atomic mass is the sum of protons and neutrons
Atomic Number (Z) = Atomic mass (A) - Number of Neutrons
The element has 71 electrons and a charge of +1 , so
Number of protons = 71 + 1 = 72
Number of protons = the atomic number = 72
The element with atomic number 72 is Hafnium(Hf)
The atomic mass of Hf = 178 g/mol
Answer:
it looks good to me just pay attention to the subscriped, i always have trouble with that.
Explanation:
Answer:
1. The change in energy is 60KJ or 6.0 × 10^1 KJ
2. Endothermic reaction
Explanation:
The Enthalpy (ΔU) for the mixture is given as 215kJ and the workdone (W) on the mixture is - 155KJ. Hence, the change in the energy (ΔH) ofthe mixture is computed using the equation below:
ΔH = ΔU + w
Where,
ΔH= Change in energy
ΔU= Enthalpy change
W= workdone
Therefore ΔH is:
ΔH= 215 kJ + (-155Kj)
ΔH= 60 KJ
Therefore, the change in energy is 60KJ or 6.0 × 10^1 KJ
The value is positive so it is an endothermic reaction.
An endothermic reaction happens when the energy used to break the bonds in the reactants is higher than the energy given out when bonds are formed in the products. This means that the entire reaction takes in energy, hence there is a temperature decrease in the surroundings. Endothermic reactions cannot happen spontaneously. Work is usually done in order to get these reactions to occur. When endothermic reactions absorb energy, a temperature drop is measured by the reaction.
