The kinetic energy of a hydrogen molecule travelling at 1900 m/s is(A)

1.	The kinetic energy of a hydrogen molecule travelling at 1900 m/s is(A) 1.21 x 10 20 J (B) 3,02 × 10-21 J (C) 5.99 x 10-21 J (D)6,04 x 10-18 J
Answer» mass of 1mole H molecule = 2g mass of 1 molecule = 2/(6×10²³) = 10/3 ×10^-²² g = 10/3× 10^-24 kg so, K.E = 1/2(m)(v²) = 1/2*(10/3× 10^-24 kg)×(1900)² = 601 × 10^-24 × 10^4 = 6.01×10^-18J option D

The kinetic energy of a hydrogen molecule travelling at 1900 m/s is(A) 1.21 x 10 20 J (B) 3,02 × 10-21 J (C) 5.99 x 10-21 J (D)6,04 x 10-18 J

Answer»

mass of 1mole H molecule = 2g mass of 1 molecule = 2/(6×10²³) = 10/3 ×10^-²² g = 10/3× 10^-24 kg

so, K.E = 1/2*(m)*(v²) = 1/2*(10/3× 10^-24 kg)×(1900)² = 601 × 10^-24 × 10^4 = 6.01×10^-18J

option D