Nitrogen from a gaseous phase is to be diffused into pure iron at 700°c. if the surface concentration is maintained at 0.1 wt% n, what will be the concentration 1 mm from the surface after 10 h? the diffusion coefficient for nitrogen in iron at 700°c is 2.5 × 10−11 m2/s.

Forests and meadows are often cut down to make way for farms or large number of new homes. what are some of the elements of ecosystems that are lost when plants in these areas are removed?

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

An object displaces 652 ml of water. the volume of the object is: 0.652 cm³ 6.52 cm³ 65.2 cm³ 652 cm³