The force of gravity between two objects depends on?

Please help

Fill in the coefficients that will balance the following reaction: a0cr2(so4)3 + a1agno3

What will most likely happen when two bromine atoms bond together?

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?