Balance this chemical equation :

HCl + NaOH → NaCl + H2O

The reaction of the burning of carbon in oxygen is represented by equation

$\mathrm{C}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right) \stackrel{}{\to } {\mathrm{CO}}_2\left(\mathrm{g}\right)+\mathrm{Heat}+\mathrm{Light}$

When 9.0 g of solid carbon is burnt in 16.0 g of oxygen gas the mass of carbon dioxide gas formed would be:

(Note: Atomic mass of C-12,o u, O=16.0 u)

Select from the following figure(s) that correctly represent(s) the experimental set-up for the verification of conservation of mass in a chemical reaction.
${\mathrm{BaCl}}_2\left(\mathrm{aq}\right)+{\mathrm{Na}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to {\mathrm{BaSO}}_4\left(\mathrm{s}\right)+2\mathrm{NaCl}\left(\mathrm{aq}\right)$

According to Dalton's atomic theory, the smallest particle of matter is___________.

The law of constant proportion was stated by Proust as?