Can I apply visa free transit in 2 times during a trip ?

I'll stay overnight in Guangzhou's hotel on 7 August,then in order to fly to Vietnam in the morning of 8 August, Can I get a 24-hoursvisa free transit in baiyun airport ?

After Vietnam tour finished, I'll fly from Ho Chi Minh City (Vietnam) to GZ on 14 August, stay overnight in a hotel again,then fly to Xiamen ,China in the morning of 15 August for other 6 days tour there. I have to apply a single entry to China ONLY in Sydney (I am Austrlian passport holder). In 14 of August Do I need apply a 24-hour visa free transit if I need to get out of hotel ? or my SINGLE entry visa to China is enough to cover ? because from 14 August to 20 August I am in China, then when the Xiamen tour finish I will fly back to Sydney.