Learn German: Wird exakt dasselbe geschehen? - Will exactly the same thing happen?

When you refer to a general, unspecified "thing" or abstract event rather than a specific masculine or feminine noun, German defaults to the neuter form. Here, dasselbe stands alone to mean "the same thing".

Is it ever correct to write das selbe as two separate words?

No, it must always be written as one single word: dasselbe. Even though the first half changes like a definite article (der, die, das) and the second half changes like an adjective, they are always fused together.

Could I say "Wird exakt das Gleiche geschehen?" instead?

Yes, but there is a famous, subtle difference in German! Dasselbe refers to the exact identical thing. Das Gleiche refers to two different things of the exact same type. For a repeating event, people often use them interchangeably, but dasselbe strongly implies the exact same historical situation repeating itself.

Why use geschehen instead of the more common word passieren?

Both mean "to happen." Passieren is the everyday word used for daily occurrences or minor accidents. Geschehen sounds slightly more formal, serious, or dramatic, which perfectly fits the tone of wondering if a major event will repeat.

Why is geschehen at the very end of the sentence?