premise: These widely advertised products , which are used primarily for washing clothes , are based on high-sudsing , synthetic organic actives ( sodium alkylbenzenesulfonates ) and contain up to 50 % by <mask> of sodium tripolyphosphate or a mixture of sodium tripolyphosphate and tetrasodium pyrophosphate .
hypothesis: the proper context for <mask> here should be the vertical force exerted by a mass as a result of gravity