Cân 2,1g NaHCO3 cho vào 250 ml nước cất, ta thu được dung dịch B. Tính pH và đệm năng của dung dịch B. Biết axit H2CO3 có pKa1 = 6,35; pKa2 = 10,33.

Can someone me with questions 12 and 13 plz.

Let the ed50 of a recreational drug be defined as the amount required for 50% of a test group to feel high or get a buzz. if the ed50 value of ethanol is 470 mg/kg body mass, what dose would a 70 kg party goer need to quickly consume in order to have a 50% chance of getting a buzz? 235 mg 470 mg 32,900 mg 35,000,000 mg

The number of moles of a given mass of a substance can be found without knowing its molecular formula or molar mass. true false