A salt crystal has a mass of 0.12 mg. How many NaCl formula units does it contain?

Video transcript

Hey everyone, we're asked to determine the amount in formula units of sodium bicarbonate, found in 0.52 mg of baking soda powder. In order to answer this question, we're going to need to determine our molar mass of sodium bicarbonate. Starting off with our sodium, we can see that we have one of sodium And so we're going to multiply this by its atomic mass of 22.99 g per mole. And this will get us to a total of 22.99. Moving on to our hydrogen, we have one of hydrogen and we're going to multiply this by its atomic mass of 1.008 Which again will get us to 1.008 g per mole. And for carbon, we have one of carbon. And so we're going to multiply that by its atomic mass of 12. g per mole. And lastly we have three of oxygen. And we're going to multiply that by its atomic mass of 16.0 And this will get us to a total of 48 g per mole. When we add this all up, we end up with a molar mass of 84.008 g per mole. Now that we have our molar mass, let's go ahead and start off with our 0.5, two mg. So we know that we have 10 to the third milligrams per one g. And since we calculated our molar mass, we're going to use our 84.008 grams of sodium bicarbonate per one mole. And since we want to go and convert into formula units, We know that one mole Of sodium bicarbonate is going to be equivalent to 6.02, 2 times 10 to the 23rd formula units of sodium bicarbonate. And this is going to be avocados number. So when we cancel out our units and calculate this out, we're going to end up with a total of 3.7 times 10 To the Formula units of sodium bicarbonate. And this is going to be our final answer. So I hope this made sense. And let us know if you have any questions.