User:Master Fakhrey

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Heat Energy $[Q]$

Although the discoverer or inventor of the heat energy equation is unknown, the French chemist Antoine Lavoisier was one of the first scientists to be known for using this formula. In the mid 1780's, Lavoisier first used the formula to determine how much heat was given off by an animal. He kept the guinea pig in an enclosed container in order to melt ice and used the heat energy formula to determine his objective.

Heat energy formula

$Q=C_{p}\times m\times \Delta T$

Where:

$\Delta Q$ is heat energy,

$m$ is mass,

$\Delta T$ is change in temperature,

$C_{p}$ is specific heat.

Table of specific heat capacities

Table of specific heat capacities at 25 °C (298 K) unless otherwise noted

Notable minima and maxima are shown in maroon

Substance	Phase	(mass) specific heat capacity cp or cm J·g−1·K−1	Constant pressure molar heat capacity Cp,m J·mol−1·K−1	Constant volume molar heat capacity Cv,m J·mol−1·K−1	Volumetric heat capacity Cv J·cm−3·K−1	Constant vol. atom-molar heat capacity in units of R Cv,m(atom) atom-mol−1
Air (Sea level, dry, 0 °C (273.15 K))	gas	1.0035	29.07	20.7643	0.001297	~ 1.25 R
Air (typical room conditionsA)	gas	1.012	29.19	20.85	0.00121	~ 1.25 R
Aluminium	solid	0.897	24.2		2.422	2.91 R
Ammonia	liquid	4.700	80.08		3.263	3.21 R
Animal tissue (incl. human)	mixed	3.5			3.7*
Antimony	solid	0.207	25.2		1.386	3.03 R
Argon	gas	0.5203	20.7862	12.4717		1.50 R
Arsenic	solid	0.328	24.6		1.878	2.96 R
Beryllium	solid	1.82	16.4		3.367	1.97 R
Bismuth	solid	0.123	25.7		1.20	3.09 R
Cadmium	solid	0.231	26.02			3.13 R
Carbon dioxide CO2	gas	0.839*	36.94	28.46		1.14 R
Chromium	solid	0.449	23.35			2.81 R
Copper	solid	0.385	24.47		3.45	2.94 R
Diamond	solid	0.5091	6.115		1.782	0.74 R
Ethanol	liquid	2.44	112		1.925	1.50 R
Gasoline (octane)	liquid	2.22	228		1.64	1.05 R
Glass	solid	0.84
Gold	solid	0.129	25.42		2.492	3.05 R
Granite	solid	0.790			2.17
Graphite	solid	0.710	8.53		1.534	1.03 R
Helium	gas	5.1932	20.7862	12.4717		1.50 R
Hydrogen	gas	14.30	28.82			1.23 R
Hydrogen sulfide H2S	gas	1.015*	34.60			1.05 R
Iron	solid	0.450	25.1		3.537	3.02 R
Lead	solid	0.129	26.4		1.44	3.18 R
Lithium	solid	3.58	24.8		1.912	2.98 R
Lithium at 181 °C	liquid	4.379	30.33		2.242	3.65 R
Magnesium	solid	1.02	24.9		1.773	2.99 R
Mercury	liquid	0.1395	27.98		1.888	3.36 R
Methane at 2 °C	gas	2.191	35.69			0.66 R
Methanol (298 K)	liquid	2.14	68.62			1.38 R
Nitrogen	gas	1.040	29.12	20.8		1.25 R
Neon	gas	1.0301	20.7862	12.4717		1.50 R
Oxygen	gas	0.918	29.38	21.0		1.26 R
Paraffin wax C25H52	solid	2.5 (ave)	900		2.325	1.41 R
Polyethylene (rotomolding grade)	solid	2.3027
Silica (fused)	solid	0.703	42.2		1.547	1.69 R
Silver	solid	0.233	24.9		2.44	2.99 R
Sodium	solid	1.230	28.23			3.39 R
Steel	solid	0.466
Tin	solid	0.227	27.112			3.26 R
Titanium	solid	0.523	26.060			3.13 R
Tungsten	solid	0.134	24.8		2.58	2.98 R
Uranium	solid	0.116	27.7		2.216	3.33 R
Water at 100 °C (steam)	gas	2.080	37.47	28.03		1.12 R
Water at 25 °C	liquid	4.1813	75.327	74.53	4.1796	3.02 R
Water at 100 °C	liquid	4.1813	75.327	74.53	4.2160	3.02 R
Water at −10 °C (ice)	solid	2.11	38.09		1.938	1.53 R
Zinc	solid	0.387	25.2		2.76	3.03 R
Substance	Phase	Cp J/(g·K)	Cp,m J/(mol·K)	Cv,m J/(mol·K)	Volumetric heat capacity J/(cm3·K)

Food energy calculation method

1. Use the measuring cylinder to measure 20 cm3 of water into the boiling tube.

2. Clamp the boiling tube to the clamp-stand.

3. Measure the temperature of the water with the thermometer. Record the temperature in a suitable results table.

4. Choose a piece of dry food and find its mass using the balance. Record the mass in the table.

5. Impale the piece of food carefully on a mounted needle.

6. Light the Bunsen burner and hold the food in the flame until it catches alight.

7. As soon as the food is alight, put it under the boiling tube of water as shown. Try to make sure that as much of the heat from the burning food as possible is transferred to the water. Do this by keeping the flame under the tube.

8. Hold the food in place until the food has burnt completely. If the flame goes out, but the food is not completely burnt, quickly light it again using the Bunsen burner and replace the food beneath the tube.

9. As soon as the food has burned away completely and the flame has gone out, measure the temperature of the water again. Before measuring, stir the water carefully with the thermometer and note down the highest temperature reached in the results table.

10. Repeat the procedure for other foods.

11. Calculate the rise in temperature each time.

12. Calculate the energy released from each food by using this formula.

$E_{food}={\frac {m_{water}\times \Delta T\times 4.2}{m_{food}}}$

Where:

$E_{food}$ is food energy,

$m_{water}$ is water mass,

$\Delta T$ is change in temperate,

$m_{food}$ is the food mass.