Achemical solution contains 2% salt. how much salt is in 4 ml of solution?

How air particles exert a pressure on the inside of the balloon

If a polyatomic ionic compound has gained two hydrogen ions, then how does its name begin?

The activation energy for the reaction no2(g)+co2(g)⟶no(g)+co(g) is ea = 300 kj/mol and the change in enthalpy for the reaction is δh = -100 kj/mol . what is the activation energy for the reverse reaction?