That's why molecular substances like ice and water can be physically broken or separated into portions, while only a chemical reaction can break apart the molecules themselves, like how water can be split into hydrogen and oxygen using electricity.

这就是为什么像冰和水这样的分子物质可以物理破碎或分成几部分，而只有化学反应才能分解分子本身，就像水如何用电分解成氢和氧一样。