Measurements also show that a certain sample of the unknown compound contains 6.2 mol of oxygen and 4.1 mol of nitrogen. Write the complete chemical formula for the unknown compound.

The chemical formula for the unknown compound : N₂O₃

Given

6.2 mol of oxygen and 4.1 mol of nitrogen.

Required

The chemical formula

Solution

Chemical formulas can be expressed in terms of empirical or molecular formulas.

The empirical formula shows the simplest mole ratio of a compound

Meanwhile, the molecular formula shows the actual ratio of the number of elements that make up the compound

We divide the two known moles by the smallest mole (moles of nitrogen)

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"

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.