how many moles of h20 are in 12.4 g h20?

12.4g of water has 0.689 moles of water.

Explanation:

Molar weight of = 16 + 2 = 18g

One mole of weighs 18g.

Hence, 12.4g of water has 0.689 moles of water.

weight of any object is given by

w = m*g

where m is mass of the object and g is the acceleration due to gravity.

for earth the value of g is 9.8 m/s^2 so

w=117.6 n m=12 g=?

117.6=12g => g=9.8 m/s^2

which is the force of gravity on earth.

c. 4.54 x 10–12 j happens to be correct