Answer: [Kr] 5s24d10 is the element Cadmium, Cd. It has 48 electrons.
Fred is using interactive for sure. It requires a response from you, not just looking, watching, or listening.
I believe it the answer is 3412
Hrxn = Q reaction / mol of reaction
mol of reaction = M * V = 10 * 1 = 10 mmol = 0.01 mol
Q water = m * C * (Tf - Ti)
= (10 + 10) (4.184) (26-20) = 502.08 J
Q reaction = - Q water = -502.08 J
Hrxn = -502.08 / (0.01) = - 50208 J = - 50.21 kJ/mol
To answer this question you need to know how to calculate the molecular weight of a molecule. The compound is having 1 Mg atom and 2 Cl atom, thus the molecular weight should be:
24.305+ 2*35.453= <span>95.211 gram/mol.
Then, the mass of 3 mol of MgCl would be:
3 mol * 95.211 gram/mol= 285.633 gram</span>