Question

How many minutes should 750 mL of water take to boil?

Answer 1

Heat require to boil 750 g water can be calculated from the formula:

`Q=m* s* dT`

Here, Q is the heat

m, is the mass

s is the specific heat

dT is the temperature difference

Here ,

m, is 750 g

s of water is 4.2 cal g⁻¹ K⁻

dT , as water is boiled from 25 to 100 C

Q=
`750* 4.2* (100 - 25)`

= 236250 J

Assuming if input power is 1000 W then time required is:

Q=
`P* t`

`236250 = 1000 * t`

t = 236.25 s

Thus time required to boil 750 g of water will be 236.25 s

Answer 2

Heat require to boil 750 g water from 25 C0to 100 C0

Q = m s dT

= 750 g * 4.2 cal /g /K * (100 - 25)

= 236.25 * 103 J

If stove is supplying 1000 W power then time required is:

Q = P *t

236.25 * 103 = 1000 * t

t = 236.25 s

Thus 236.25 s is required by a 1000 W power supplying stove to boil 750 mL water