A 50.00 g sample of an unknown metal is heated to 45.00°C. It is then placed in a coffee-cup calorimeter filled with water. The
calorimeter and the water have a combined mass of 250.0 g and an overall specific heat of 1.035 cal/g•°C. The initial temperature of the calorimeter is 10.00°C. The system reaches a final temperature of 11.08°C when the metal is added.
2 answers:
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Answer:
The heat absorbed by the water is 228,948.48 J
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
In this way, between heat and temperature there is a direct proportional relationship (Two magnitudes are directly proportional when there is a constant so that when one of the magnitudes increases, the other also decreases; and the same happens when either of the two decreases .). The constant of proportionality depends on the substance that constitutes the body and its mass, and is the product of the specific heat and the mass of the body. So, the equation that allows to calculate heat exchanges is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the variation in temperature.
In this case:
- c= 4.184
- m=855 g
- ΔT= Tfinal - Tinitial= 85 °C - 21°C= 64 °C
Replacing:
Q= 4.184 *855 g* 64 C
Solving:
Q= 228,948.48 J
<u><em>The heat absorbed by the water is 228,948.48 J</em></u>
Number of moles = 5.7 moles of oxygen.
<u>Explanation:</u>
We have to convert number of molecules into number of moles by dividing the number of molecules by Avogadro's number.
Here number of molecules of oxygen given is 34.1 × 10²³ molecules.
Now we have to divide the number of molecules by Avogadro's number as,
Number of moles =
=
= 5.7 moles
So here molecules is converted into moles.