Answer:
2Cu + O2 ----------------> 2CuO
I think it would be these three answers ionic , covalent , and polar covalent
2BF₃ + 3Li₂SO₃ ----> B₂(SO₃)₃ + <u>6LiF
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I think the answer is C. An element or compound that cannot be physically separated. Sorry if im wrong.