A 2.80 kg mass is dropped from a height of 4.50 m. Find its potential energy when it reaches the ground.

123.48J

Explanation:

Given parameters:

Mass of the ball  = 2.8kg

Height  = 4.5m

Unknown:

Potential energy  = ?

Solution:

The potential energy is the energy due to the position of a body. It is mathematically given as;

      P.E   =  mgh

m is the mass

g is the acceleration due to gravity

h is the height

 Now insert the parameters and solve;

          P.E  = 2.8 x 4.5 x 9.8  = 123.48J

  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

no simpler subs form complex ones. synthesise = make