Question

How much water

can be heated from
15 C to boiling with
a gas burner with an
efficiency of 35% by
burning 100 l of
natural gas?​

Answer 1

The mass is
`m = 3.75 \ kg`

Step-by-step explanation:

From the question we are told that

The initial temperature is
`T_1 = 15^oC`

The final temperature is
`T_2 = 100 ^o C \ (boiling point )`

Generally the maximum heat produced by 1 Liter of natural gas is
`9000 \ cal`

So the amount of heat produced by 100 L is

`E = 9000 * 100`

=>
`E = 9000 00 \ cal`

Generally given that the efficiency is
`\eta = 0.35`

Then actual heat received by the water is

`H = 0.35 * E`

=>
`H = 0.35 * 9000 00`

=>
`H = 315000 \ cal`

Converting to kcal

=>
`H = 315000 \ cal = (315000)/(1000) = 315 \ kcal`

Generally the specific heat of water is

`c_w = 1 kcal/ kg \cdot ^oC`

Generally the heat received by the water is mathematically represented as

`H = m * c_w * (T_2 - T_1)`

=>
`315 = m * 1 * ( 100 - 15 )`

=>
`m = 3.75 \ kg`