Ap Chem THERMOCHEMISTRY
25 g of water is cooled from 74°c to 39°c how much Heat energy is associated with this reaction in kilojoules?
-3.661 Kilojoules
what is the total energy lost to cool 523 grams of water vapor from 134°C to -46°C of ice kilocalories?
-396.65 kilocalories
using Hess' law calculate the heat of the reaction for the following reaction: Use heat of formation values. 2F₂(g) + 2H₂O(l) → 4HF(g) + O₂(g) ∆H = ? kJ/mol
-521.6kJ/mol
Given the following two reactions and enthalpy data: CH₂CO(g) + 2O₂(g) → 2CO₂(g) + H₂O(g) ∆H = -981.1 kJ CH⁴(g) + 2O₂(g) → CO₂(g) + 2H₂O(g) ∆H = -802.3 kJ calculate the enthalpy change for the reaction in which methane and oxygen combine to form ketene, CH2CO, and water. 2CH₄(g) + 2O₄(g) → CH₂CO(g) + 3H₂O(g) ∆H = ? kJ/mol
-623.5kJ/mol
What is the specific heat of a 3581.4 gram sample of lithium, when its initial temperature was 157.2°C and final temperature is 183.6, with the energy released when 852 grams of Germanium is cooled from 573.3°C to 254.7°C? The specific heat of Germanium is 0.31.
0.89
convert 356 Calories (big C) into Joules
1,490,000 Joules
The reaction of magnesium with sulfuric acid was carried out in a calorimeter. This reaction caused the temperature of 27.0 grams of liquid water, within the calorimeter, to raise from 25.0°C to 76.0°C. Calculate the energy associated with this reaction in kilocalories.
1.377 kilocalories
convert 50,000 Joules into calories
11950.287 calories
How much heat is needed to boil away 5.0 L of water that's at 24.0°C in kilojoules?
12889.92 kilojoules
How much heat is released when 1.5 L of water at 24° C freezes in kilocalories?
155.7 kilocalories
What is the final temperature of a 67 gram sample of titanium, when its initial temperature was 126.4°C, with the energy released when 239 grams of Iridium is cooled from 4428°C to 2446°C? the specific heat of titanium is 0.523 J/g °C and the specific heat of iridium is 0.13 J/g °C?
1883.8°C
A 4.00 gram sample of solid gold was heated from 274K to 314K. How much energy was involved? The specific heat of gold is 0.126 J/g K.
20.16 J
How many grams of ice at -10° C could be completely melted with 17.2 Calories of heat?
203.23 grams remember you need to add the heat of fusion and the heat it takes to bring the ice from -10°C to 0°C.
A 22..0 gram sample of solid gold was heated from 200.K to 300.K. How much energy was involved? The specific heat of gold is 0.126 J/g K.
284J
convert 24◦C into Kelvin
297.15 Kelvin
If 2500 calories of heat are used to heat up 355 grams of water with an initial temperature of 24°C, what will the final temperature of the water be?
31.04°C
What is the specific heat of water in joules?
4.184
What final temperature will 2400 g of water at -15° C have after it absorbs 35.9 Calories of heat?
47.6 °C remember specific heat for ice is 2.01
convert 12,500 calories into Joules
52,300 joules
A 100-watt electric incandescent light bulb consumes __________ J of energy in 24 hours. [1 Watt (W) = 1 J/sec]
8,640,000
The reaction of magnesium with hydrochloric acid carried out in a calorimeter caused the temperature of water to change from 25.0°C to 36.0°C. In this reaction 3760J of energy was released. What mass of water was present?
81.7 grams
The reaction of magnesium with sulfuric acid was carried out in a calorimeter. This reaction caused the temperature of 55. grams of liquid water, within the calorimeter, to raise from 1.0°C to 28.°C. what is the mass of tungsten can be heated from 40.6°C to 87.3°C? the specific heat of tungsten is 0.133 J/g°C
998 grams
True or false: Combustion reactions are usually endothermic.
False
True or false: If an exothermic reaction takes place in water, heat is absorbed from the water and the temperature of the water increases.
True
true or false heat goes from the source with lower heat to higher heat
false
What is the equation to find heat?
q= mc∆t where q = heat energy m = mass c = specific heat ∆t = change in temperature