Live practice

Write the mass-action expression. Pressure increase favours two gas moles on the left; temperature increase favours the endothermic forward direction; catalyst changes only the rate.

Every single bond is sigma; a double bond adds one pi and a triple bond adds two pi bonds.

Down group 1, ionisation enthalpy falls, so electron loss becomes easier. Down group 17, size and shielding increase and the tendency to gain an electron falls.

For a shell n, l=0,...,n−1; for a subshell l, mₗ=−l,...,+l.

For elements, compare moles of atoms. One mole of Cl₂ contributes two moles of chlorine atoms.

Translate every condition into an equation and retain exact values throughout the ellipse calculation.

The last line satisfies the original conditions and supplies every requested part.

Choose one ace and four non-aces.

For a real square root, \(x-1\ge0\), hence \(x\ge1\). Also \(\sqrt{x-1}\ge0\), and every non-negative \(y\) occurs when \(x=y^2+1\).

The first pair shares 4, so it is not disjoint. The second shares e, so it is not disjoint. No integer can be both even and odd, hence the third intersection is empty.

Connect it in parallel between the two points, with positive terminal towards higher potential. Its very high resistance minimises current drawn.