A straight-chain alkane will have a boiling point higher than a branched-chain alkane due to the greater surface area in contact, and thus greater van der Waals forces, between adjacent molecules.
ɐ stɹˈeɪttʃˈeɪn ˈælkeɪn wɪl hæv ɐ bˈɔɪlɪŋ pˈɔɪnt hˈaɪɚ ðˌænə bɹˈæntʃttʃˈeɪn ˈælkeɪn dˈuː tə ðə ɡɹˈeɪɾɚ sˈɜːfɪs ˈɛɹiə ɪn kˈɑːntækt, ænd ðˈʌs ɡɹˈeɪɾɚ vˈændɜː wˈɑːlz fˈoːɹsᵻz, bᵻtwˌiːn ɐdʒˈeɪsənt mˈɑːlɪkjˌuːlz.