In performing a gravimetric analysis experiment of a salt mixture the student wa
ID: 915986 • Letter: I
Question
In performing a gravimetric analysis experiment of a salt mixture the student was instructed to weigh a cruicible, Add the sample reweigh it then heat mixture to constant weight. When shebegins the experiment she notices that sides of the cruicibles is wet with beads of the unknown liquid fromits uses in previous lab period. She proceeds to carry out the experiment anyway. Provided that she does everything else correctly, the yield of product would be: too high correct too low could eighter be too high or too low The temperature of a 15-g sample of lead metal increases from 22 degreeC to 37 degreeC upon the addition of 29.0 J of heat. The specific heat capacity of the lead is j/g. k. 7.8 1.9 2.9 0.13 .29 The specific heat capacity of solid copper metal is 0 385 j/g-K How many Joules of heat are needed to raise the temperature of a 1.55-kg block of copper from 33 0degreeC to 77 5 degreeC? 1.79 times 10^3 2.66 times 10^4 0.00558 26.6 5.58 times 10^6 A chemical reaction that absorbs heat from the surroundings is said to be and has a deltaH at constant pressure. endothermic, positive exothermic, negative endotherm, negative exothermic, positive The reaction 4AI(s)+302 (g) 2AI2O3(s) deltaHw is and therefore heat Is by the reaction. endothermic, released endothermic, absorbed exothermic, released exothermic, absorbed When 0.800 grams of NaOH is dissolved in 100.0 grams of water, the temperature of the solution increases from 25.00 degreeC to 27.06 degreeC. The amount of heat absorbed by the water is j. (The specific heat of water is 4.18 J/g degree C.) 861 681 168 960 list all of the following for which a MSDS can be a useful reference reactivity information lethal dosage control measures.Explanation / Answer
23. a
24.
Q= m.c.dT
C = Q/m.dT = 29.0 J/ (15g x 15ºC) = 0.13 J/g.grd
25.
Q = 1550g x 0.385 J/g.K x 44.5K = 2.66x104 J
26.a
27.c
28.
100 g x 4.18 J/g.Kx 2.06 K = 861 J
29.
a, b , c