객관식How many atoms are present in a 12.0 g sample of lithium (Li)? (Atomic mass of Li = 6.94 g/mol)105views
객관식A sample contains 1.25 grams of CH_4 and no other substances. What is the mole fraction of O_2 in this sample?95views
객관식A copper sample has a mass of 63.5 g. How many moles of copper are present in the sample? (Atomic mass of Cu = 63.5 g/mol)146views
객관식A solution has a concentration of 0.025 M HCl. How many moles of H+ are present per liter in this solution? (Use the decimal form of your answer.)86views