can someone do #3 . aparantly I had significant figure issues 1. An unknown meta
ID: 548856 • Letter: C
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can someone do #3 . aparantly I had significant figure issues
1. An unknown metal and container were weighed and the mass was 109.73 g. After pouring some of the metal out of the container and into a large test tube, the new mass was found to be 64.01 g. What is the mass of the metal? 45.74 2·The Styrofoam cups were weighed and their mass was found to be 6.09 g. Deionized water was added and the new mass was 51.55 g. What is the mass of the water? 3. The temperature of the water in the calorimeter measured 253 The temperature of the boiling water bath measured 100.9 when the metal is transferred to the calorimeter with the water and the lid is placed on the cup, the new temperature measured 27.0 Temperature of the water in the calorimeter: Temperature of the hot metal: Equilibrium temperature of water and metal: what is the T of the water? 100.9C 210C 1"( Determine Qwater 4.184.45·4G-1.7 what is the QMetal? ·25.3 what is the T of the metal? Determine the specific heat of the metal. PRE-LAB POINTS:Explanation / Answer
Significant figures rules
Perform operations as usual... then
account for the significant figures of each number.
Recall:
- ZEROS to the left do NOT matter ; 0.02 and 0.2 will have 1 sig. fig (digit = 2)
- ZEROS between numbers, DO matter 0.0202 and 0.202 will have 3 sig fig (digits 2, 0 and 2)
- ZEROS to the right, DO matter, since those show precise data i.e. 2.0 vs. 2.00 exists (2 sig fig. vs 3 sig. fig)
Then... apply rule, round as required
* Addition / Subscraction --> round answer to the LEAST sig. fig of the operation ( i.e. 2 sig fig vs. 3 sig fig --> round to 2 sig. fig)
* Multiplication/Division --> round answer to the LEAST sig. fig of the operation ( i.e. 2 sig fig vs. 3 sig fig --> round to 2 sig. fig)
dT is given by:
dT = Tf-Ti
dT = (27.0-25.3) = 1.70 (keep 3 sig fig; since there are 3 sig fig)
Q2
Qwater
Qwater = mwateR*Cpwater(dT) = 45.46*4.184*1.70 = 323.347888 J = 323 J ( keep 3 sig fig)
find Qmetal
Qmetal = -Qwater = -323.347888 = -323 J
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