When a mass rests on a surface, the surface "pushes up" on the object with a force that is equal in
magnitude to the gravitational force exerted by the object on the surface. this is sometimes called the
"normal force." suppose that a 30 kg basset hound rests on a couch. what is the magnitude of the normal
force that the couch exerts on the dog? hint: the acceleration due to gravity on the earth's surface is 9.8
m/s2 and 1 newton = 1 kg m/s2

294 N

Explanation:

Since the Normal Force is equal to the weight of the dog, we have:

Where:

is the mass of the dog

is the acceleration due to gravity on the Earth's surface

Solving:

  the grams     of oxygen gas   that can be produced     is 20.6   grams of o₂

calculation

2liclo₃ →   2 licl + 3 o₂

step 1:   find the moles of liclo₃

moles = mass÷ molar mass

from periodic table the molar mass of liclo₃ =6.9 +35.5   +(16 x3) =90.4 g/mol

moles=38.7 g÷90.4 g/mol=0.4281   moles

step 2:   use the   mole ratio   to calculate the moles of o2

from equation above, liclo₃: o₂   is 2: 3  

therefore the moles of   o₂=0.4281 moles x3/2 =0.6422   moles

step 3: find mass   of o₂

mass= moles x molar mass

from periodic table the   molar mass of   o₂ = 16 x2= 32 g/mol

mass=0.6422   moles   x   32 g/mol = 20.6 grams of o₂