Answer:
Molar mass of the gas = 15.15 g/mol
Explanation:
PV = nRT
Where,
P = pressure
n = No. of moles
R = Gas constant
T = Temperature
P = 698 torr, 1 torr = 0.00131579 atm

Temperature = 111 °C = 100 + 273.15 = 384.15 K
V = 48.7 L
R = 0.082057 L atm/mol K
Now, PV = nRT


           =1.4189 mol
Molar mass = Mass/ No. of  moles
                     = 21.5/1.4189
                     =15.15 g/mol
 
        
             
        
        
        
1.The use of land is determined both by physical factors such as topography, climate, soil types as well as human factors such as population density, technological capability and culture and traditions etc.
2. Common property resources (environmental) are natural resources owned and managed collectively by a community or society rather than by individuals.
3.
Wind erosion is a natural process that moves soil from one location to another by wind power. ... Wind erosion can be caused by a light wind that rolls soil particles along the surface through to a strong wind that lifts a large volume of soil particles into the air to create dust storms.
4. Terrace cultivation or terrace agriculture method of growing crops on sides of hills or mountains by planting on graduated terraces built into the slope. Though labour-intensive, the method has been employed effectively to maximize arable land area in variable terrains and to reduce soil erosion and water loss.
HOPE THIS HELPS....
        
             
        
        
        
Answer:
O(Oxygen) 
Explanation:
2+2+4=8
And the eighth element of the periodic table is Oxygen 
 
        
             
        
        
        
Answer:
Explanation:
Groundwater is stored in the open spaces within rocks and within unconsolidated sediments. Rocks and sediments near the surface are under less pressure than those at significant depth and therefore tend to have more open space. For this reason, and because it’s expensive to drill deep wells, most of the groundwater that is accessed by individual users is within the first 100 m of the surface. Some municipal, agricultural, and industrial groundwater users get their water from greater depth, but deeper groundwater tends to be of lower quality than shallow groundwater, so there is a limit as to how deep we can go.