According to newton's law of universal gravitation, if you triple the distance between two masses, the force they
a.
becomes one-third of the original.
b.
will be nine times larger.
c.
becomes one-ninth of the original.
d.
will also triple.

C)

Explanation: This fact is related with the expression of the Newton's Law of Universal Gravitation given by:

F = G m1*m2/d^2

where G si the gravitational universal constant

d is the distance between masses

if we triple the distance, we have a resultant force dividing by 9 this means one-ninth of the original force.

  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

if they have a finite resultant