Answer:
The chemical reaction is: AB + CD ---> AC + BD (ΔH= - )
Explanation:
After the reaction between two reactants, two products are generated.
As the products have less energy than the reactants, this energy is released and ΔH is negative
Answer:
The stratosphere
contains the ozone layer
,
is used by airplanes,
has strong, steady winds
, and
increases in temperature as altitude increases
.
Explanation:
The stratosphere is the atmospheric layer between 10 km and 50 km above the Earth's surface.
It includes the ozone layer, which is at an altitude of about 20 km.
It has strong, steady winds that can reach as high as 220 km/h.
Passenger aircraft generally fly in the lower levels of the stratosphere, at altitudes of about 10 km to 12 km.
Temperatures increase with altitude, from -50 °C at 10 km to -3 °C at 50 km.
A is wrong. The mesosphere (altitude 50 km to 85 km) is the coldest of the atmospheric layers, with temperatures as low as -90 °C at 85 km.
Answer:
they have thin membranes to allow diffusion of substance for short distance
they are numerous to increase the surface area of absorption
hope this helps