Question

Calculate the kinetic energy (in joules) of a mole of water molecules traveling at 11.7 m/s.

Answer 1

Atomic mass of hydrogen= 1 u
Atomic mass of oxygen = 16 u
Molecular mass of water=1*2+16*1
=18 u
Mass of 1 mole of water= 18 g=0.018 kg
KE=1/2mv²
=1/2*0.018*11.7²
=1.23 J (approx.)

Answer 2

`k=1.23J`

Step-by-step explanation:

1. The equation to calculate the kinetic energy is:

`k=(mv^(2) )/(2)` (Eq.1)

where, m=mass, v=velocity, k=kinetic energy

2. Find the mass of one mole of water,
`H_(2)O`:

Atomic weight of H = 1
`(g)/(mol)`

Atomic weight of O = 16
`(g)/(mol)`

Molecular weight of
`H_(2)O` = (2*1) + 16

Molecular weight of
`H_(2)O` = 18
`(g)/(mol)`

3. Convert the mass of
`H_(2)O` from g to Kg:

`18g*(1Kg)/(1000g)=0.018Kg`

3. Replace quantities in Eq.1:

`k=(0.018g*(11.7(m)/(s))^(2))/(2)`

`k=1.23J`