Calculation in transition metal​

When will le chatelier's principle come into effect? at the beginning of a reaction, when there are only reactants when a reaction has reached chemical equilibrium when a catalyst is added to a reaction mixture when a reaction is occurring but not yet at equilibrium

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?

How many moles of no2 will form when 3.3 moles of cu are reacted with excess hno3?