Friday, May 24, 2013

Specific heat of metal

     Our goal in this lab is to find the specific heat of an unknown metal. In order to figure this out a needed to collect several things. I needed to collect temperature of a cup if water, the temperature of boiling water, the weight of the water in the cup, the weight of the metal, and the temperature changed when you added the heated metal into the cup if water.
       
In order to figure out the specific heat of our metal we needed to learn about an equation that would give us it,  q=mc(ΔT) . The q in this equation stands for number if Joules, m stands for mass, c stands for specific heat, and the Δ and T are the change in temperature. By knowing any three of these four things you can solve for whatever you need. In order to find what we need we will first have to plug our information in with the water to find the joules of it. Then we will use the joules of water to put into our equation for our mental. We will have the mass, the joules, and the change in temperature. We simply solve the equation and are given our product. Our metal can be 
         Aluminum: .897
         Brass: .385
         Copper: .385
         Lead: .129
         Stainless Steal: . 490
         Zinc: .39
The specific heat of each metal is given as well. The specific heat is the rate at which heat is lost or kept by an object. Specific heat is joules divided by grams times Celsius. 
                                              J/(GxC)
I collect the mass of the cup, my metal, and the weight of the water. I also needed the temperature of the cup of water, the boiling water, and the metal. 



                TEST1

  • Weight of cup(g): 3.044g
  • Weight of cup and water (g): 100.46g
  • Weight of metal(g): 26.422g
  • Temperature of water: 22.7C
  • Temperature of metal: 99.6C
  • Temperature of water + metal: 24.9C
               TEST 2
  • Weight of cup: 3.02g
  • Weight of cup + water: 101.59g
  • Weight of metal: 26.422g
  • Temperature of water: 24.6C
  • Temperature of metal: 99.9C
  • Temperature of water + metal: 27.8C

I used one equation and had to do it four times.
photo.JPG
With my tests I came to the conclusion that I had stainless steel. My first test hit right on the mark and was .3 away from the theoretical amount. In my second test I got a slightly larger number at .57. This was still closest to .49 of stainless steel which supported my first test. 






  

Friday, May 10, 2013

Chemical Reactions

Copper and Nitric Acid


In this lab we conducted seven chemical reactions. We did this to see what the different kinds of reactions look like, synthesis, decomposition, single replacement, double replacement, and combustion. 






Cu + 2NHO3 -----> H2 + Cu (NO3)2

We can predict the outcome by knowing that it is a single replacement. Then since we know all of the sub types of a single replacement reaction we can guess the outcome. In this case we have a replacement of a hydrogen atom in an acid by a metal. Copper is a copper colored metal while nitric acid is a clear liquid. When we drop the copper in a brownish gas emerged.