2 sentences

1. 碳酸钙是构成大理石的主要成分。

   tàn​suān gài shì gòu​chéng dà​lǐ​shí de zhǔ​yào chéng​fèn.

   Calcium carbonate is the main component of marble.

   Source: Dong Chinese Dictionary

2. 碳酸在受热时会分解成水和二氧化碳。

   tàn​suān zài shòu​rè shí huì fēn​jiě chéng shuǐ hé èr​yǎng​huà​tàn.

   Carbonic acid decomposes into water and carbon dioxide when heated.

   Source: Dong Chinese Dictionary