Answer:
126.99g
Explanation:
NiO has a molar mass of 74.7 g/mol. This means that one mole of nickel (II) oxide has a mass of 74.7 grams. We can use stoichiometry/dimensional analysis to figure out how many grams are in 1.7 moles.

Groups 13-16, hope this helps!
I think the correct answer from the choices listed above is option A. The key characteristic by which Dmitri Mendeleev arranged his periodic table was that the elements are arranged in increasing atomic number. Hope this answers the question.
Answer:
Theoretical moles of V are 1.6 moles
Explanation:
The theoretical yield of a reaction is defined as the amount of product you would make if all of the limiting reactant was converted into product.
In the reaction:
V2O5(s) + 5Ca(i) → 2V(i) + 5CaO(s)
Based on the reaction, 1 mol of V2O5 needs 5 moles of Ca for a complete reaction. As there are just 4 moles, <em>limiting reactant is Ca.</em> As there are produced 2 moles of V per 5mol of Ca, Theoretical moles of V are:
4 moles of Ca × (2mol V / 5Ca) = <em>1.6 moles of V</em>
<em></em>
I hope it helps!
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