URGENT You add 6.2 g iron to 23.80 mL of water and observe that the volume of iron and water together is 24.59 mL . Calculate the density
of iron. Answer in two significant figures with proper units.

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next

How many grams of oxygen gas are contained in a 15 l sample at 1.02 atm and 28°c? show your work.