Mass of metal=45.00 grams
Initial temp= 20.0 degrees Celcius
Final temp= 87.0 degrees Celcius
4.184 J/g-specific heat of H2O
The metal was heated up from initial temp to final temp. What would be the metal's highest temperature?
The specific heat of the metal was calculated to be 7.93x10^-1 J/g*degC
Also, another question I have is about enthalpy.
1. Calculate the standard enthalpy change for reaction at 25 deg C. Standard enthalpy formations of
Mg(OH)2(s) +2HCl(g) right arrow MgCl2(s) +2H2O (g)
What is the enthalpy of the rxn in kJ?
I'm calculating everything and got -385 . When I entered the answer it was wrong, so I'm unsure of where I went wrong.
Mg(OH)2(s)=-924.5
HCl(g)=-92.3
MgCl2=-641.3
H2O=-241.8
Your post is not well organized. I assume those temperatures at the top are Tinitial and Tfinal for H2O and not the meal.
[mass metal x specific heat metal x (Tfinal-Tinitial)] + [mass H2O x specific heat H2O x (Tfinal-Tinitial)] = 0
#2.
dS0 = (n*dSo products) - (n*dSo reactants)
Substitute and solve. Post your work if you want us to find the error.
To find the metal's highest temperature, we need to use the formula for heat transfer:
Q = m * c * ΔT
Where:
Q = Heat transferred (in Joules)
m = Mass of the metal (in grams)
c = Specific heat of the metal (in J/g*°C)
ΔT = Change in temperature (in °C)
First, let's calculate the heat transferred (Q) using the specific heat of water (4.184 J/g) since the metal was heated up:
Q (water) = m (water) * c (water) * ΔT (water)
Where:
m (water) = Mass of water (in grams)
c (water) = Specific heat of water (in J/g*°C)
ΔT (water) = Change in temperature of water (final temp - initial temp)
As the information about the water is not provided, we cannot calculate Q (water).
However, we can calculate the heat transferred by the metal to the water. The heat transferred by the metal is equal to the heat absorbed by the water:
Q (metal) = -Q (water)
Since no heat is lost or gained from the system (assuming an isolated system), the heat transferred by the metal (Q(metal)) can be written as:
Q (metal) = m (metal) * c (metal) * ΔT (metal)
Where:
m (metal) = Mass of the metal (in grams)
c (metal) = Specific heat of the metal (in J/g*°C)
ΔT (metal) = Change in temperature of the metal (final temp of metal - initial temp of metal)
Now, let's rearrange the formula to solve for the final temperature of the metal (T(final)):
Q (metal) = m (metal) * c (metal) * ΔT (metal)
Rearranging for T(final):
T(final) = (Q (metal) / (m (metal) * c (metal))) + initial temp of the metal
Now, let's substitute the values into the formula:
m (metal) = 45.00 grams
c (metal) = 7.93x10^-1 J/g*°C
ΔT (metal) = final temp of the metal - initial temp of the metal = 87.0°C - 20.0°C
T(final) = (Q (metal) / (m (metal) * c (metal))) + initial temp of the metal
T(final) = [(m (metal) * c (metal) * ΔT (metal)) / (m (metal) * c (metal))] + initial temp of the metal
Simplifying the equation:
T(final) = ΔT (metal) + initial temp of the metal
Finally, we can substitute the values and calculate the highest temperature of the metal:
T(final) = 87.0°C - 20.0°C = 67.0°C
Therefore, the metal's highest temperature would be 67.0 degrees Celcius.