{ "items" : [
    { "id" : "http://dbpedia.org/resource/Kerogen"
      "properties" : {
        "http://www.w3.org/2000/01/rdf-schema#comment" : [ "Kerogen (Greek κηρός \"wax\" and -gen, γένεση \"birth\") is a mixture of organic chemical compounds that make up a portion of the organic matter in sedimentary rocks. It is insoluble in normal organic solvents because of the high molecular weight (upwards of 1,000 daltons or 1000 Da; 1Da= 1 atomic mass unit) of its component compounds. The soluble portion is known as bitumen. When heated to the right temperatures in the Earth's crust, (oil window ca. 50–150 °C, gas window ca."] } } }
