How much heat energy in megajoules is needed to convert 7 kilograms of ice at -9c to water at 0c
2 answers:
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
<span>E=Lm</span>·m (Where Lm is a specific constant for the material/substance and m is the mass)
<span>Lm</span> for solid water (i.e. ice) is 334
We can now solve for E
E= <span>334⋅2</span> <span>Kj</span> =668<span>Kj</span>
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.
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Answer:
C. They have the same change of momentum.
Explanation:
Let "m" be the mass and "v" the velocity.
According to the property of conservation of momentum, when objects 1 and 2 collide:
Therefore, one can conclude that the change in momentum (Δ(mv)) has the same magnitude but opposite sign for any two objects regardless of how much heavier one might be than the other.
They have the same change of momentum.