Determine how many grams of one of the chemicals that you investigated in the experiment are required to achieve the following temperature: hot pack, 55° C (131° F) The chemical in question is Na2CO3. The other substance in a hot pack would be water. How do I calculate the amount of Na2CO3 that is needed to heat water up to 55° C?

True, the standard unit for volume is liters which can be represented by either a lower case "l" or a capital "l"

Answer two atoms of oxygen;

Answer is: the equilibrium  shifts toward the reactants, to the left side of chemical reaction.it is because lead(ii) nitrate dissociates in water: pb(no₃)₂ → pb²⁺(aq) + 2no₃⁻(aq).according to lechatelier's principle, the position of equilibrium moves to counteract thechange (more lead cations, common ion), the position of equilibrium will move so that the concentration ofproducts decrease and concentration of reactants of chemical reaction increase.read more on -