Molar mass of 13c = 13 grams
number of moles = mass / molar mass
therefore,
number of moles = 7 / 13
To know the number of atoms in 7/13 moles, we simply multiply the number of moles by Avogadro's number as follows:
number of atoms = (7/13) x 6.022 x 10^23 = 3.2426 x 10^23 atoms
The correct option is A.
To calculate the binding energy, you have to find the mass defect first.
Mass defect = [mass of proton and neutron] - Mass of the nucleus
The molar mass of thorium that we are given in the question is 234, the atomic number of thorium is 90, that means the number of neutrons in thorium is
234 - 90 = 144.
The of proton in thourium is 90, same as the atomic number.
Mass defect = {[90 * 1.00728] +[144* 1.00867]} - 234
Note that each proton has a mass of 1.00728 amu and each neutron has the mass of 1.00867 amu.
Mass defect = [90.6552 + 145.24848] - 234 = 1.90368 amu.
Note that the unit of the mass is in amu, it has to be converted to kg
To calculate the mass in kg
Mass [kg] = 1.90368 * [1kg/6.02214 * 10^-26 = 3.161135 * 10^-27
To calculate the binding energy
E = MC^2
C = Speed of light constant = 2.9979245 *10^8 m/s2
E = [3.161135 * 10^-27] * [2.9979245 *10^8]^2
E = 2.84108682069 * 10^-10.
Note that we arrive at this answer because of the number of significant figures that we used.
So, from the option given, Option A is the nearest to the calculated value and is our answer for this problem.
In easy words the connection between Reactants, Products and Limiting reactants is as follow,
Reactants and Products:
Reactants are the starting materials for the synthesis of final synthesized materials called as products.
Example:
CH₄ + 2 O₂ → CO₂ + 2 H₂O
In above reaction Methane (CH₄) and Oxygen (O₂) are the reactants while, CO₂ and H₂O are the products.
Reactants, Products and Limiting Reactants:
Considering the same example it is seen that for one mole of CO₂ two moles of O₂ are required to completely convert into CO₂ and H₂O. If either of the reactant is taken less than the required amount then it will act as a limiting reactant because it will consume first leaving the second reactant present in excess as compare to it. Hence, we can say that the limiting reactant is the starting material which controls the amount of product being formed.
