$625/oz x ?oz = $5,000
Solve for ?oz
?oz x 31.1 g/oz = x grams.
q = grams x specific heat Au x (Tfinal-Tinitial)
Make sure mass and specific heat are in the same units.
cThe price of gold is $625 per troy ounce at this writing. How much heat (in J) is needed to raise the temperature of $5000.00 worth of gold from 29.5 oC to 70.5 oC?
(1 troy oz = 31.10 g and the specific heat of Au is 25.42 J/(moloC).)
I got 5.125, which isn't right.
Dissolving 7.19 g of CaCl2 in enough water to make 377 mL of solution causes the temperature of the solution to increase by 3.32 oC. Assume the specific heat of the solution and density of the solution are the same as water′s (about 4.18 J/goC and 1.00 g/cm3, respectively) Calculate ΔH per mole of CaCl2 (in kJ) for the reaction under the above conditions.
I got 80.76, which also isn't right.
The thermochemical equation for the burning of ethyl alcohol is
C2H5OH(l) + 3O2(g) --> 2CO2(g) + 3H2O(l) ΔH = -1,367 kJ
What is the enthalpy change (in kJ) for burning 3.20 g of ethyl alcohol?
I got 94.95
A reaction that is used to propel rockets is N2O4(l) + 2N2H4(l) --> 3N2(g) + 4H2O(g). This reaction has the advantage that neither product is toxic, so no dangerous pollution is released. When the reaction consumes 10.0 g of liquid N2O4, it releases 124 kJ of heat. What is the value of ΔH (in kJ per mole N2O4) for the chemical equation as written
1140
Any help is appreciated!
1 answer