Often, the adverbial particle か is used in the middle of a sentence, in the same way that it is as a sentence ending particle. The main differences are as follows:
Adverbial Particle: 副助詞（ふくじょし） - Highlights uncertain things '不確（ふたし）かであること'. This is the same か as in どこか 'somewhere'.
Sentence Ending Particle: 終助詞（しゅうじょし） - Highlights doubts and questions '疑問（ぎもん）や質問（しつもん）'. This is a direct question.
In the case of the adverbial particle か and 'uncertain things', this will almost always be followed by a word that is seeking information about the uncertain thing.

• 忘年会（ぼうねんかい）に社長（しゃちょう）が来（く）るか分（わ）かりますか？
  Do you know if the CEO is coming to the end of year party? (Literally, 'If the CEO is coming, do you know?')
• これで足（た）りるか分（わ）かる？
  Do you know if this is enough? (Literally, 'If this is enough, do you know?')
• 何（なん）でこのビルを壊（こわ）すか知（し）っていますか。
  Do you know why they are destroying this building? (Literally, 'Why they are destroying it, do you know?')
• お祭（まつ）りは何時（なんじ）に終（お）わるか知（し）ってる？
  Do you know what time the festival is going to end? (Literally, 'What time it will end, do you know?')

As can be seen in these examples, sometimes the adverbial particle will appear by itself, and sometimes it will appear together with the sentence ending particle in the same sentence. However, due to the 'uncertainty' being displayed by the adverbial particle, the question marker at the end of the sentence is not required.