Calcium is obtained industrially by electrolysis of molten cacl2 and is used in aluminum alloys. how many coulombs are needed to produce 13.3 g of ca metal? if a cell runs at 15 a, how many minutes will it take to produce 13.3 g of ca(s)?

64 000 C; 71 min

Explanation:

1. Number of coulombs

a. Write the equation for the half-reaction.

Ca²⁺ + 2e⁻ ⟶ Ca

b. Calculate the moles of Ca

Moles of Ca = 13.3 g Ca × (1 mol Ca/40.08 g Ca) = 0.3318 mol Ca

c. Calculate the moles of electrons

Moles of electrons = 0.3318 mol Ca × (2 mol electrons/1 mol Ca) = 0.6637 mol electrons

d. Calculate the number of coulombs

No. of coulombs = 0.6637 mol electrons × (96 485 C/1 mol electrons)

= 64 000 C

It takes 64 000 C to produce 13.3 g of Ca.

2. Time required

Q  = It  

t = Q/I = 64 000 C/15 C·s⁻¹ = 4270 s

t = 4270 s × 1 min/60 s = 71 min

The process will take 71 min.

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.