今度はきっと成功するはずです
means It should be successful this time
.
今度 means this time, きっと is an adverb indicating certainty, 成功する is a suru verb that means to succeed and はず, a noun, which can appear at the end of a sentence followed by だ or です to mean 'to be supposed to (do)'. It is used when the speaker draws a conclusion from preexisting understandings.
だから、こんなにいい結果が出たわけです
means In this way, I got a good outcome
.
だから is a conjunction indicating consequence, こんなに is an adverb meaning in this way, いい is an adjective meaning good, 結果 is a noun meaning result, 出た is the past form of 出る that, in this case, means to get. Finally, わけ is a noun that means reason. This noun can be followed by だ or です at the end of a sentence to mean 'that's why' and it can follow:
- Adjectives and verbs in the dictionary or ta-form.
- Adjectival nouns or nouns + na/no or datta
In this case it follows 出た.
As for 実験のやり方を変えてみたんです
, which means I changed the way I experimented
, you may consult: