Define
if delta H is negative what kind of reaction is it
exothermic
which signs for q and w are correct when the system is losing heat and doing work
-q, -w
which will have the greatest amount of heat change with the smallest amount of heat added
lead=.128
water=4.184
sulfur=0.706
arsenic=0.329
lead=.128
What is Hess’s Law?
Hess’s law is an important result of the first law of thermodynamics. It states that the enthalpy change in a chemical or physical process is the same whether it is performed in one step or several steps.
The reaction
4Al (s) + 3O2 (g) ¬ 2Al2O3 (s) DHe = -3351 kJ
is __________, and therefore heat is __________ by the reaction.
exothermic, released
bomb calorimeter use what formula
C*delta T=q
what is specific heat
the energy needed to raise 1 g of a substance 1 degree C
What is the correct formula to use when figuring out how much energy is needed to make a 40.0g sample of water steam from 105C to 110C
q = mC∆T
Given that standard molar enthalpies of formation of NO(g) and NO2(g) are respectively 90.3 kJ/mol and 33.2 kJ/mol. Calculate the enthalpy change for the reaction 2NO(g) + O2(g) →2NO2(g).
ΔH= ∑ΔHproducts– ∑ΔHreactants
ΔH= 2(33.2)-[2(90.3)+0]
ΔH= -114.2kJ
endothermic has a ___ sign for delta H
positive
) Given the following reactions
Fe2O3 (s) + 3CO (s) ¬ 2Fe (s) + 3CO2 (g) ∆H = -28.0 kJ
3Fe (s) + 4CO2 (s) ¬ 4CO (g) + Fe3O4 (s) ∆H = +12.5 kJ
the enthalpy of the reaction of Fe2O3 with CO
3Fe2O3 (s) + CO (g) ¬ CO2 (g) + 2Fe3O4 (s)
-59.0kJ
energy required?
2.00 grams
20.0 to 25.0 C
0.902J/gC
exothermic has a ____ sign for delta H
negative
what is the formula for delta U
q+w
25 Joules
5 gram substance
change 2C
what is the specific heat
2.5J/gC