The amount of UVA radiation hitting a surface at sea level in a lightly clouded day is about 70W/m2. About half of that can be absorbed by the skin. A typical carbon- carbon bond requires 348 kJ/mol to break. A person lies on the beach for about 1 hour without sunscreen (i. e. fully exposed to UVA radiation). Estimate the number of C-C bonds broken in this person’s back (about 0.18 m2) over that period. Assume that the average wavelength of UVA is 335 nm.

Explanation:

energy of solar radiation = 70 W / m²

energy absorbed in 1 hour by an area of .18 m²

= 70 x .5 x .18 x 60 x 60 J

= 22.68 x 10³ J

bond energy of i mole bond = 348 x 10³ J

bond energy of 6.02 x 10²³ bonds = 348 x 10³  J

bond energy of one bond = 57.8 x 10⁻²⁰ J  

No of bonds broken by energy 22.68 x 10³

= 22.68 x 10³  / 57.8 x 10⁻²⁰

= .3923 x 10²³

= 39.23 x 10²⁰ .

answer: e.   sour taste

explanation: acids are those substances which dissociates in water to give ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. acids are sour in taste. example: hcl

bases are those substances which dissociates in water to give ions or accepts ions. as they dissociate to give ions, they act as electrolytes and thus are electrically conductive. bases are bitter in taste. bases are slippery in nature.