Para poder simular la reacción que ocurre en una bolsa de aire, en el laboratorio se produjo nitrógeno mediante la reacción de amoniaco con el oxido de cobre . La ecuación química es la siguiente. NH3+CuO-->Cu+H2O+N2
a)Si reaccionan 80 g de NH3 con 160 g de CuO, determina el reactivo limitante y el de exceso
b)Determina la masa de N2, producida mediante la reacción
c) Calcula el rendimiento si se obtienen 17 g de N2

For cyclohexane compounds drawn in a chair conformation:   -axial bonds are vertical  -equatorial bonds are parallel to two bonds within the ring.  thus, as i assume the chair conformation is drawn:   -the x group is in an axial position, as are the five other vertical bonds.  -three axial bonds are on the top face of the ring  -the other three axial bonds are on the bottom face  the position of the second substituent on each ring carbon is equatorial.  gauche groups must be on an adjacent carbon such as carbon 6 and carbon 2, and also gauche groups are rotated by 60 degrees relative to each other.  drawing the newman projections for c1–c2 and c1–c6 aids in visualizing the groups that are gauche to the y group on c1.  click this link and watch some academic videos that may you more understand the topic 

Ans. : frostbite is when exposure to cold temperatures causes freezing to the skin or other tissues. it most commonly affects the hands, feet, and face. the longer areas are exposed to cold, typically the worse the frostbite. the water temperature used for rewarming a frostbitten part should be : (102 -105) f degrees.