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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1) 29.8 C
At the beginning, the metal is at higher temperature (70.4 C) while the water is at lower temperature (23.6 C). When they are put in contact, the metal transfers heat to the water, until they reach thermal equilibrium: at thermal equilibrium the two objects (the metal and the water have same temperature). Therefore, since the temperature of the water at thermal equilibrium is 29.8 C, the final temperature of the metal must be the same (29.8 C).
2) 6.2 C
The temperature change of the water is given by the difference between its final temperature and its initial temperature:
where
Substituting into the formula,
And the positive sign means that the temperature of the water has increased.
3) -40.6 C
The temperature change of the metal is given by the difference between its final temperature and its initial temperature:
where
Substituting into the formula,
And the negative sign means the temperature of the metal has decreased.
Answer:
<h2>12 m/s²</h2>Explanation:
The acceleration of an object given it's mass and the force acting on it can be found by using the formula
f is the force
m is the mass
From the question
f = 6000 N
m = 500 kg
We have
We have the final answer as
<h3>12 m/s²</h3>Hope this helps you