Question

please please please answer this is very important i will mark u as brainlist pls explain it clearly 2 , 3 , 4 , 5

Answer 1

$\underline{\textsf{Question 2}}$

How much energy is released when 5 g of water at 20° C changes into ice at 0°C?

$\underline{\textsf{Answer}}$

We know
Specific Heat Energy of Water(SHE)=4.2 g^-1 K^-1
Change in Temperature=20°C
Mass=5g

Heat Energy=Mass×SHE×Changes in Temperature
=5×4.2×20
=420J

Now ,420J energy released to reach water from 20°C to 0°C.
But till it is not in ICE.

Latent Heat of fusion generally means own heat of A solid.
MEANS when It release it will become ice

Latent Heat of fusion ice=336 J g^-1

Latent heat fusion of ice
Mass×336
=5×336
=1680J

Total Heat Energy
=420J+1680J
=2100J

$\boxed{\mathbf{2100J}}$

$\underline{\textsf{Answer 3}}$

(1)We know that
Mass=150g
Energy Released=75000J

Mass×Latent Heat of metal=75000J
150×Latent Heat of metal=75000J
Latent Heat of metal=75000/150
=500J g^-1

$\boxed{\mathbf{{500J\:g}^{-1}}}$

(2)Specific Heat Capacity=200 J kg^-1
In gram=0.2 J g^-1
If Temperature goes from 800°C to -50°C changes cause 850°C
Mass=150g

Energy=Mass×SHE×change into Temperature
=150×0.2×850
=25500J

$\boxed{\mathbf{25500J}}$

$\underline{\textsf{Answer 4}}$

Mass=100 g
From 20°C to 0°C change in Temperature=20°C
Specific Heat Energy of water=4.2J g^-1

Heat Energy=Mass×Changes In Temperature×SHE
=100×20×4.2
=8400J

Now To form ice it will release Latent Heat
We know Latent Heat of Fusion of ice=336 J g^-1
Energy Released=Mass×Latent Heat of ice
=100×336
=33600 J

Now Again
Mass=100 g
Specific Heat Capacity=2.1 J g^-1 of ice
Change in Temperature from 0°C to -10°C
=10°C
Heat Energy=100×2.1×10
=2100J

Total Heat Energy
8400J+2100J+33600J
=44100

Time=73.5 min
73.5 min in seconds=4410 seconds

Watt=Joule/seconds
=44100/4410
=10 W

$\boxed{\mathbf{10\:W}}$