Chemistry

For both work and heat, there are positive and negative signs, which mainly depend on transfer of energy. When work is done on the system, it will have a negative sign, but when work is done by the system, we will use a positive sign. This would be similar to how we view heat in chemical thermodynamics. If a system absorbs heat, it will be a positive sign. But if heat releases from a system, it will be a negative sign. 

${\left(\frac{C^{14}}{C^{12}}\right)}_t=\frac{{\left(\frac{C^{14}}{C^{12}}\right)}_{t=0}}{{\left(2\right)}^n}$

n = 3

t = 3 * 1580

= 4740 years

Amphoteric oxides are those which can react with both acid and base

SnO₂, PbO₂ and Al₂O₃ are amphoteric oxide

SiO₂, P₂O₅, CO₂ are acidic oxides

CO, NO and N₂O are neutral oxides

–C º N $?\underset{\begin{array}{l}\left|\text{?}\right|\\ O\end{array}}{C}$ , – CH₃ are –R group which is deactivating

– $\ddot{N}H$ – $\stackrel{\begin{array}{l}O\\ \left|\text{?}\right|\end{array}}{C}$ – CH₃ and – $\ddot{N}H$ – CH₃ due to presence of lone pair in nitrogen atom behaves as activating (+R) group.

Classical smog contains SO₂

E_cell = 0 – log2

= – 0.03 (0.3)

 = – 0.009

 = – 9 * 10^–3 V

x = 9