Polarity

The CH4O molecule is polar. This means that there is an uneven distribution of the electrons in the molecule. In CH4O, the oxygen that is bonded to the carbon is very electronegative, and the hydrogens that are bonded to the carbon are not very electronegative. This creates a more negative end of the molecule, even though there is a hydrogen bonded to the oxygen. See the picture above so you can visualize this.

The bonds are also polar in nature. Hydrogen has an electronegativity value of 2.2, and carbon has an electronegativity value of 2.5, meaning that the arrow showing the electronegativity difference between the bonds is from the hydrogen to the carbon. This is true for all three hydrogens bonded to the carbon. Oxygen has an electronegativity value of 3.5, making it more electronegative than carbon. Thus the arrow showing polarity would be going from the carbon towards the oxygen. Hydrogen is obviously less electronegative than oxygen, meaning that the arrow would go from hydrogen to the oxygen. All of this is show in the picture above.