Question

1) A student performed this experiment with a watch glass that has a area of 956,667,666,076,834.6 nm². If the area of a stearic acid molecule is 0.21 nm² and it took 0.0000021 grams of stearic acid to form the monolayer, what is his approximate value for Avogadro's number? Molar mass of stearic acid is 282 g/mol.

2) A student calibrated a dropper and found that it delivered 1.00 ml of solution in 57 drops. If it took 5 drops to form his monolayer, and the stearic acidconcentration was 1.76 g/L, what mass (g) of stearic acid was in his monolayer?

3) If a watch glass has an area of 86.11 cm², what is its area in nm²?

4) A watch glass has a radius of 5.35 cm. What is the area of the watch glass in cm²?

5) If a student has a crystal with 818,795,544,682,724,600,000,000 molecules of iodine, what mass (g) of iodine does she have?

6) A student massed 22.65 grams of elemental iron. How many moles (mol) of iron does this represent?

7) When converting from mass in grams to moles it is necessary to divide by what? a)atomic number b) molar mass c) Avogadro's number d) the number of atoms in a mole

8) A student fills a balloon with air, to a volume of 20.0L. If it took 529,841,802,202,048,000,000,000 molecules of air to fill the balloon how many moles (mol) of air does that equal?

9) Avogadro's number is equal to what, and it represents what? a) 6.022e23, atoms in a molecules b) 6.022x10²³, atoms in a gram. c)6.022x10²³, atoms and/or molecules in a mole. d)6.022x10^-23, atoms and/or molecules in a mole.

Answer 1