Calculate the number of moles in:

1)6g of C

2) 48g of Mg

3) 8g of O2

4) 170g of NH3

1) 72 mole

2)1152 mole

3)256 mole

4) 2890 mole

Explanation:

very important for u

number of mole= given mass/molecular mass

symbolically : n= m/Mm

1) first atomic mass (carbon =12)

n=6gram × 12gram /mole

n=72mole

2) atomic mass (Magnesium =24)

48 gram × 24 gram /mole

n= 1152 mole

3)atomic mass (oxygen = 16×2=32

n= 8 gram × 32 gram/ mole

n= 256mole

4) atomic mass ( Nitrogen =14 , hydrogen = 1×3

14+3=17

n= 170 gram × 17 gram / mole.

n= 2890 mole

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.