Mass of solid gold = 6g
Initial temperature = 274K
Final temperature = 325K
Specific heat capacity of gold = 0.129J/g°C
Amount of energy used = ?
The amount of energy absorbed in changing in giving a temperature rise to a body is given as a product of its mass, specific heat capacity and change in temperature.
H = m x C x Ф
where m is the mass of the body
c is the specific heat capacity
Ф is the change in temperature
Now the unknown is H;
We need to convert the given temperatures into °C from kelvin so we can work with it;
Initial temperature = 274K, in °C; 274 - 273 = 1°C
Final temperature = 325K, in °C; 325 - 273 = 52°C
Now input the parameters and solve;
H = 6 x 0.129 x (52 - 1) = 39.5J
(a) 3.96 x 10⁵C
(b) 4.752 x 10⁶ JExplanation:
(a) The given charge (Q) is 110 A·h (ampere hour)
Converting this to A·s (ampere second) gives the number of coulombs the charge represents. This is done as follows;
=> Q = 110A·h
=> Q = 110 x 1A x 1h [1 hour = 3600 seconds]
=> Q = 110 x A x 3600s
=> Q = 396000A·s
=> Q = 3.96 x 10⁵A·s = 3.96 x 10⁵C
Therefore, the number of coulombs of charge is 3.96 x 10⁵C
(b) The energy (E) involved in the process is given by;
E = Q x V (i)
Q = magnitude of the charge = 3.96 x 10⁵C
V = electric potential = 12V
Substitute these values into equation (i) as follows;
E = 3.96 x 10⁵ x 12
E = 47.52 x 10⁵ J
E = 4.752 x 10⁶ J
Therefore, the amount of energy involved is 4.752 x 10⁶ J
A- 25.9 kJ
ΔH of formation is defined as the amount of energy that is involved in the formation of 1 mole of substance.
ΔH of rust is -826kJ/mol, that means when 1 mole of rust is formed, there are released -826kJ.
Moles of 5.00g of Fe₂O₃ (Molar mass: 159.69g/mol) are:
5.00g ₓ (1 mole / 159.69g) = 0.0313 moles of Fe₂O₃.
If 1 mole release -826kJ, 0.0313 moles release:
0.0313 moles ₓ (-826kJ / 1 mole) = -25.9kJ
Thus, heat involved is:A- 25.9 kJ
you can use hash law
The energy involved is -14,000 J or -14 kJ.
The specific heat for water is 4.184 J/g • °C. We know the mass of the water as 50.0 grams, and the phrase "..water cools a total of 68°C." means the temperature changed 68°C. (in this case the sign would be negative as the temperature cooled). So the energy involved is:
q= msΔT=(50.0g)(14.184J/g. °c) (-68°c)= -14.000J <or> 14kJ
Explanation:The field of thermochemistry (and thermodynamics) deals with the changes in heat and energy in chemical systems for both chemical reactions and physical processes involving chemicals. Different characteristic thermodynamic parameters have developed over time with two of them being specific heat (sometimes called specific heat capacity) and the other heat capacity. Specific heat, s, (or specific heat capacity, CP) is a measure of the quantity of heat required to change the temperature of a substance by one degree Celsius (or Kelvin). This gives it typical units of J/g • °C. The equation for the heat (or energy) for a change in temperature for a substance is:
where q is the amount of energy or heat changing, m is the mass of the substance in grams, s is the specific heat (CP is specific heat capacity) for the substance, and T is temperature (ΔT is the temperature change)/Heat capacity, C, on the other hand is the heat required to raise the temperature one degree Celsius (or Kelvin) for a given quantity of a substance (units J/°C. For example, the specific heat for pure copper metal is 0.385 J/g • °C whereas the heat capacity for 50 grams of copper is 50gx0.385J/g•°C=19.3J/°C. The equation for it is:C=ms
where C is the heat capacity with m and s defined above.
The difference in the energy involved in carbon single bond, double bond, and triple bond are as mentioned below-Methane - 349 kJEthene - 681 kJEthyne - 815 kJThese differences in energy depend on the number of bonds formed, bond lengths, sizes of atoms that are involved in the bond formation, affinities of the electron, electronegativity differences.
Hence, the shorter the bond length, the higher is the bond energy .The bonds in double and triple bonds that are formed in ethene and ethyne respectively are shorter than the bonds formed in single bonds formed in methane. Ethyne has the highest bond energy and methane has the lowest bond energy.