All categories

3 years ago

How much heat energy in megajoules is needed to convert 7 kilograms of ice at -9c to water at 0c

Physics

2 answers:

gayaneshka [121]3 years ago

7 0

We can solve this by using the formulas provided to us by calorimetry.

The energy (heat) that is needed to change a given mass of some solid into its liquid form is

E=Lm·m (Where Lm is a specific constant for the material/substance and m is the mass)

Lm for solid water (i.e. ice) is 334 $\frac{Kj}{Kg}$

We can now solve for E

E= 334⋅2 Kj =668Kj

This is the minimum energy required to melt 2 kg of ice. Remember that this energy will in no way change the temperature of the water since every amount of this energy is needed just to melt the solid itself. Even more energy would be needed to increase the end temperature.

Musya8 [376]3 years ago

6 0

The latent heat of fusion of water is 344 j/p.This will take 344x300 or 100200 J to melt the ice. once it melted its at oc

You might be interested in

What is the force that opposes the movement of an object through water??

anastassius [24]

In air, you'd call it air resistance, pilots call it drag. In water, some call it
water resistance, or just plain drag.

Whatever it's called, it's the friction between the object and the fluid, plus
the force needed to push the fluid out of the way to let the object get through.

5 0

3 years ago

Read 2 more answers

A 5.7 kg block attached to a spring executes simple harmonic motion on a frictionless horizontal surface. At time t = 0s, the bl

Genrish500 [490]

Answer:

Explanation:

Given

mass of block $m=5.7\ kg$

at $t=0 s$

displacement is $x=-0.7\ m$

velocity $v=-0.8\ m/s$

acceleration $a=2.7\ m/s^2$

suppose $x=A\cos (\omega t+\phi )$ is the general equation of SHM

where A=amplitude

$\omega$ =natural frequency of oscillation

therefore velocity and acceleration is given by

$v=-A\omega \sin (\omega t+\phi )$

$a=A\omega ^2\cos (\omega t+\phi )$

for t=0

$-0.7=A\cos (\phi )---1$

$v=-0.8=-A\omega \sin(\phi)---2$

$a=2.7=-A\omega ^2\cos(\phi )----3$

divide 1 and 3 we get

$\omega ^2=\frac{27}{7}$

$\omega =\sqrt{\frac{27}{7}}$

Now square and 1 and 2 we get

$(0.7)^2+(\frac{0.8}{\omega })^2=A^2$

$A^2=0.49+0.166$

$A=0.81\ m$

3 0

2 years ago

Do sound waves always travel in straight lines explain

babunello [35]

They travel like waves. Just throw rock at lake you will see wave. When it bumps to barrier barrier reflects some part of it . Not like a line lika a wave

3 0

2 years ago

When a puddle of water evaporates, does the water change into a new kind of matter

PIT_PIT [208]

Evaporated water changes form into gas

8 0

2 years ago

How can understanding velocity help to prevent a mid-air collision

dsp73

Answer:

To maintain enough time to prevent a collision, a system operating in air traffic where aircraft speed does not

fall below 100 km/h (most medium-sized UAVs and GA aircraft) will need to be able to detect obstacles which

subtend an arc-width of as small as 0.125 mra

7 0

2 years ago