The Federal Trade Commission is investigating Chevron’s acquisition of Hess oil company, the second inquiry the independent agency has opened this week of a major oil industry merger. Chevron and Hess said in separate filings that the FTC is seeking additional information and documentary materials related to Chevron’s proposed $53 billion purchase of Hess, announced in October. The statements Friday follow an announcement earlier this week that the FTC is reviewing ExxonMobil’s proposed $60 billion acquisition of Pioneer Natural Resources. If completed, the Exxon and Chevron deals would be among the largest mergers in the energy industry in two decades.