Ethanol with H₂SO₄ at 443k forms ethene while at 413K forms ethoxy ethane. Explain it ?

When ethanol is heated with conc.H₂SO₄ at 443k (or) 170°C 1 mole underoges dehydration to form ethene but at 413K 2 moles undergo dehydration to form ether.
$\text{ ii) }{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\underset{443 \mathrm{k}}{\overset{\mathrm{conc}. {\mathrm{H}}_2{\mathrm{SO}}_4}{\to }}{\mathrm{CH}}_2={\mathrm{CH}}_2+{\mathrm{H}}_2\mathrm{O}$
$2{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH} \underset{413 \mathrm{K}}{\overset{\mathrm{conc}. {\mathrm{H}}_2{\mathrm{SO}}_4}{\to }} {\mathrm{C}}_2{\mathrm{H}}_5-\mathrm{O}-{\mathrm{C}}_2{\mathrm{H}}_5+{\mathrm{H}}_2\mathrm{O}$