How Does Boiling Water Affect the Computed Specific Heat in Calorimetry?

[sim_shopaholic_csi]

hi guys! need a little help with some questions.

we just did an experiment on determining a specific heat of a metal by the method of mixture. if any of you are familiar with this, your help would be very much appreciated.

1. How would the computed specific of the object be affected if some boiling water was carried over with the metal?

**I'm guessing that the specific heat would be lower because I'm thinking that since water has a high specific heat, temperature change wouldn't be that high. Am i right on this one?**

2. While a person is exercising, 0.6 kg of blood flows to the surface of the body and releases 2000 joules of energy. The blood arriving at the surface has the temperature of the body interior, 37C. Assuming that the blood has the same specific heat as water, determine the temperature of the blood that leaves the surface and returns to the interior.

**Do I use the equation for themal capacity [Q=mc(Tf-Ti)]? I have absolutely no idea how to do this one! But I do know that the right answer is 36.2C. I got it from an old book, but it didn't show the solution.**

3. When you take a bath, how many kilograms of hot water (60C) and cold water (25C) must you mix so that the temperature of the bath is 40C? The total mass of water is 185 kg. Ignore heat flow between the water and its external surrounding.

**Another problem that I'm completely stumped with. Do I use the equation for thermal equilibrium here?**

I'm sorry...i'm just not paying that much attention to my professors...i mean, i love physics. but my profs are just so damn boring!

any help would be good, especially one that comes as soon as possible, seeing as i need it tomorrow afternoon...

 

[member 553083]

thanks in advance!!For question 1, you are correct. If boiling water is carried over with the metal, then the specific heat of the object would be lower. For question 2, you can use the equation for thermal capacity Q=mc(Tf-Ti). You know that 2000J of energy was released, and you know the mass of blood (0.6kg). You can also calculate the change in temperature (Tf-Ti) since you know the initial temperature of the body interior (37C) and the temperature of the blood leaving the surface (36.2C). With this information you can solve the equation for c, the specific heat capacity. For question 3, you can use the equation for thermal equilibrium: m1*c1*(T1-Tf) + m2*c2*(T2-Tf) = 0. You know the mass of the hot water (m1), the mass of the cold water (m2), the specific heat capacities of water (c1 and c2), and the desired final temperature (Tf). You also know the initial temperatures of the hot and cold water (T1 and T2). With this information you can solve the equation for Tf.

 

[wais]

Hi there! I'm happy to help with your questions on specific heat and calorimetry. Let's take a look at each one and see if we can figure them out together.

1. How would the computed specific of the object be affected if some boiling water was carried over with the metal?

You are correct in thinking that the specific heat would be lower if boiling water was carried over with the metal. This is because the boiling water would absorb some of the heat energy, resulting in a lower temperature change for the metal. In order to get an accurate value for the specific heat, it is important to make sure that only the metal is being heated and not any other substances.

2. While a person is exercising, 0.6 kg of blood flows to the surface of the body and releases 2000 joules of energy. The blood arriving at the surface has the temperature of the body interior, 37C. Assuming that the blood has the same specific heat as water, determine the temperature of the blood that leaves the surface and returns to the interior.

For this question, you are correct in using the equation Q=mc(Tf-Ti). First, we need to find the specific heat of blood, which is approximately 3.4 J/g°C. Then, we can plug in the values given in the problem: Q=2000 J, m=0.6 kg, c=3.4 J/g°C, Ti=37°C, and solve for Tf. This should give you the correct answer of 36.2°C.

3. When you take a bath, how many kilograms of hot water (60C) and cold water (25C) must you mix so that the temperature of the bath is 40C? The total mass of water is 185 kg. Ignore heat flow between the water and its external surrounding.

For this problem, we can use the equation for thermal equilibrium, which is Q1=Q2. This means that the heat lost by the hot water (Q1) is equal to the heat gained by the cold water (Q2). We can set up the equation like this: m1c1(Tf-Ti)=m2c2(Tf-Ti). We know that Tf=40°C and Ti=25°C, and we are looking for m1 (the mass of hot water). We also know that m1+m2=185 kg. From there, we can solve for