Heat is a form to transfer energy from one body to another or from one body to its surroundings. It is closely connected to thermodynamics, enthalpy, free energy, change in the state of matter, temperature.

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What is the difference between convection and conduction?

I was having a conversation with my dad the other day and he described something as happening due to convection, and it dawned on me that I have no real clue what the difference between and convection ...
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22 views

Does Photoelectric effect occur in a micro-oven while heating food? [on hold]

Does the photoelectric effect occur while heating food on a metal plate in a microwave oven? If not, then why doesn't it occur?
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43 views

Paper Towel Soaked with Isopropanol/Water Mixture Burns without Damaging the Paper. Why?

Video: https://www.youtube.com/watch?v=_qFN1hDZwp8 If you choose not to view the video, in the first demonstration a paper towel is soaked in isopropanol. As expected, the paper towel burns. However, ...
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Mixing 1 cubic meter of HCl and NaOH: Temperature rise of a metal container?

Say I (perfectly) mix $1\ \mathrm{m^3}$ of 1 M $\ce{HCl}$ with $1\ \mathrm{m^3}$ of 1 M $\ce{NaOH}$ at standard air pressure and room temperature within a metal vessel. Heat of neutralization for ...
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27 views

What is a food-safe level of exposure of plastic containers to heat?

There are many articles about how heat can trigger the release of potentially harmful carcinogens from plastic containers into the food or liquid they contain. Specifics they fail to mention, though, ...
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8 views

Evaporating water from a combination of dietary minerals: will it work safely or react?

I've combined multiple minerals dissolved in water into a preferred ratio, but would like to evaporate some of it to heighten the concentration (let's say at 200 $^{\circ}\mathrm{C}$ in the oven). The ...
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30 views

What is Enthalpy?

At school, they teach the following two formulas: $$\Delta H = -mc\Delta T$$ and $$q= mc\Delta T$$ What i am not sure is that my teacher says that q and $\Delta H$ are the same thing but to think of q ...
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76 views

Does sodium produce water when it reacts with water?

My 10th grade chemistry book states that: "Metals react with water and produce a metal oxide and hydrogen gas. Metal oxides that are soluble in water dissolve in it to further form metal ...
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76 views

What causes the difference in heat energy released by combustion for the butanol isomers?

I am currently working on an investigation where I am burning isomers of butanol to test for the heat of combustion values to see which fuel is most efficient. The fuels I am testing are 1-butanol, ...
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34 views

Why does solvation release energy? [duplicate]

Whether dissolving acids and salts is exothermic or endothermic, depends on the lattice and solvation energy. Breaking bonds in the lattice requires energy and is endothermic - that is clear. However, ...
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3answers
147 views

How can I light a fire in this case?

Is there any gas that contains oxygen so that it doesn't require oxygen from the environment in order to burn? What I am trying to do is use LPG gas, which is fed through a pipe to a burner that is ...
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33 views

Seeking titanium compound, melting point <1600 °C, decomposes to TiO

The title says it all. I’m new to glass making, and I need a titanium compound that will render me $\ce{TiO}$ through decomposition, and has a melting point under 1600 °C. Hopefully I can get one ...
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42 views

What is the final temperature of each substance upon absorbing 2.25 kJ of heat?

Suppose that 28 g of each of the following substances is initially at 29.0 °C. What is the final temperature of each substance upon absorbing 2.25 kJ of heat? Part B) Silver My work: $2250 = ...
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1answer
57 views

Heat capacity of mixtures

After reading this recent question I was interested in how to calculate the specific heat capacity of a mixture based on the specific heat capacities of its components. According to this website the ...
3
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1answer
34 views

Is it possible to calculate specific heat capacity of a compound based on its elements' heat capacities?

What the question says. For example, if I knew the specific heat capacities of lithium and oxygen, could I work out the specific heat capacity of lithium oxide with no further information?
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23 views

How can I use sunlight to heat a RBF and reflux a reaction?

This may seem like a off topic question but I really need help on it. I am currently working on a polymerization reaction in which I'm breaking down plastic polymers into smaller molecules. However, ...
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1answer
96 views

What is a kg.cal per gram, as a heat of combustion?

I see heats of combustion given in kg [dot] calories per gram molecular weight (Handbook of Chemistry and Physics, 1969-1970). I don't know how that makes sense, as I don't know what a kg cal might ...
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228 views

Why does milk overflow when boiled?

I was wondering that like whenever I boil milk I just have to keep standing in front of it to make sure that I don't waste any milk but then I was wondering like Why does it even overflow ? In case of ...
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48 views

How to calculate the specific heat

What is the specific heat of a 20 g substance that releases 979 J of heat when changing from 70 °C to 25 °C. I started out with the following equation: $c = \frac{Q}{m\Delta T}$ $Q = 979\ ...
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28 views

How the heat a large amount of water that is safe to use?

I would like to know how heat up a large amount of water ( assumption : 100 liter ) that people could use to take their bath and also it would not be dangerous even if they accidentally ingested it ? ...
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1answer
176 views

Difference between Superheated steam and Superheated water?

I'm working on a project (school level) and in it I'll be dealing with the pressure generated by water when superheated. I could understand the concept of superheated water but superheated steam is ...
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1answer
356 views

What happens if I make a hole in a container with superheated water?

Superheated water is achieved by heating water above 100 degree Celsius under high pressure. Now, suppose the temperature at which the water is getting heated is around 250 Celsius and sufficient ...
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287 views

What is the origin of the maximum in rotational heat capacity?

The graph of rotational heat capacity above shows a small maximum before approaching the equipartition value. What is the origin/physical explanation of this maximum?
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67 views

In order to solve for this equation for heat capacity, do I need to treat it as a system of equations?

For a lab, we took the temperature of 15ml of tap water, $q_{cool}$, then added 20ml of tap water warmed to 80 degrees Celsius, $q_{warm}$. We recorded a baseline temperature of 24.8, a temperature ...
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66 views

Do I understand why heat capacity is called 'heat *capacity*'?

The notion of heat capacity seemed a little odd to me. I thought that the word 'capacity' could be throwing me off. Do I understand the notion correctly? I take the word 'capacity' to express, ...
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Scission of carbon dioxide bonds using electric arc

I've done my research on this so I've seen the questions asking about the same premise without using plants. Basically, this is a thought experiment I came up with. Whether or not I perform it ...
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2answers
351 views

Why is a tin can that appears like galvanised steel rusting?

I bought a canned pineapple and finished the content. The part of the can that is in contact with the liquid appears like galvanized steel (crystalline surface or spangles sort of appearance), while ...
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89 views

How to figure out which two solutions will emit largest heat when they are mixed in same volumes?

How can I figure out which two solutions will emit the largest heat, when they are mixed in same volumes? Then let's assume that there is are five pairs of solutions given: \begin{align} \ce{2NaOH + ...
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36 views

Which of these compounds does not liberate heat when water is added to it?

Which of these compounds does not liberate heat when water is added to it: $\ce{KNO_3}$, $\ce{NaOH}$, $\ce{CaO}$, $\ce{H_2SO_4}$, $\ce{Na}$. I know from experience that dropping sodium tablets into ...
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1answer
56 views

Chemical formula and heat

In my Physical Science class, we are learning about chemical formulas and how to balance them. I balanced this equation: $\ce{Fe2O3 + Al -> Fe + Al2O3}$ One of the other students ...
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2answers
289 views

What is the difference between tempering and hardening metals and their end products?

I think I've heard hardening is when you dunk red-hot metal into cold water, and tempering is when you take that hardened metal, heat it slightly, and then let it cool slowly. However what is the ...
2
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1answer
169 views

Exo- or endothermic? Clarification required regarding a few cases

Are the following processes exothermic or endothermic? a) When solid $KBr$ is dissolved in water, the solution gets colder. b) Natural gas ($CH_4$) is burned in a surface. c) When concentrated ...
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33 views

Ratio between heat tranfer coefficient and thermal conductivity

Consider the Robin boundary condition for the diffusion/heat equation $\mathrm{u_t=a(t)u_{xx}+f(x,t)}$: $$\mathrm{-k(t)u_x(0,t)=h(t)u(0,t)}$$ or $$\mathrm{u_x(0,t)+\frac{h(t)}{k(t)}u(0,t)=0}$$ ...
6
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275 views

How can I measure the internal temperature of a solid metal?

I’m heating up several metal blocks as part of an experiment to determine their specific heat capacities. In a nutshell, I’m heating the blocks of known mass to 100 °C, then adding them to an ...
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2answers
114 views

Heat Capacity temperature dependence and Gibbs energy

I got this problem in school as a tool to get ready for International Chemistry Olympiad, but I have some problems with this challenge. So, the problem is to calculate as precise as possible the Gibbs ...
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15 views

Why is it that reactions that cause an increase of temperature are exothermic? [duplicate]

I've been taught that if you have two aqueous reactants that react together and produce heat it is exothermic. Shouldn't that be endothermic? Did my professor misspeak? If it's gaining heat, that ...
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2answers
90 views

Thermochemistry: forms of energy & pressure

I've been in a few classes now that teach about energy, and I feel they're always so bad. There is always such a rush to start using equations to get problems solved, and I often feel I don't have an ...
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1answer
328 views

Amount of Energy Needed for Boiling a Litre of Water [closed]

What is the amount of energy (J or Wh) needed to boil one litre of tap-water in a regular kettle starting at room temperature (20°C)? The calculation itself assuming ideal and standard prerequisites ...
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251 views

How can decreasing in temperature indicate an endothermic reaction?

I’m really wondering how can decreasing the temperature refer to an endothermic reaction. I faced this when I was calculating the heat of a reaction Q in a constant-pressure calorimeter. What I ...
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22 views

Are there a few nontoxic chemicals that when rubbed together or even mixed create heat?

Are there a few nontoxic chemicals that when rubbed together or even mixed create heat? Looking for dry elements preferably that could be mixed.
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36 views

What is the heat of dissolution of sodium acetate trihydate?

Is the reaction endothermic since its crystallization is exothermic?
4
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43 views

Pre heat coal before burning

So I was wondering if pre-heating coal will improve the efficiency of a steam boiler. I did find that intake air pre-heater and water pre-heater do increase efficiency, but I could not find anything ...
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1answer
2k views

Why is the specific heat of water high?

How is the specific heat of water so high? I was reading the hyperphysics article on it but could not understand it properly.
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How do things heat one another? [duplicate]

For example, how does a gas stove heat a metal pot? A combustion reaction between the gas and the air takes place, and this releases energy due to new chemical bonds being formed. Do the atoms in ...
2
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0answers
61 views

How are pressure vessels heated?

I'm working on a project in which I'll be dealing with pressure vessels. As of now I've drawn/conceptualized everything on theory basis. The diagrams are made on the basis of theory, but then I came ...
3
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1answer
150 views

What is the temperature of heat generated from LPG gas?

I'm working on a project and I require around 300-400 degree Celsius of temperature. As of now I'm taking the normal LPG gas that is available in our house for cooking purposes for my project, but I'm ...
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7answers
6k views

How can 30 ml of water be heated in less than 10 seconds?

How is it possible to heat a tiny amount (30 ml)[1] of water to a high enough temperature to make a coffee, in less than 10 seconds and possibly instantly? Most heaters that I know of heat water ...
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1answer
80 views

Why did they provide the value for the enthalpy change of fusion?

The metal gallium melts when held in the hand; its melting point is 29.76 degrees C. How much energy as heat is removed from the hand when 5.00 grams of gallium initially at 20.0 degrees C melts? The ...
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1answer
69 views

Why does lithium move on the surface of water during the reaction?

If someone asks me to number the most notable "textbook experiments" I would definitely name "the comparison of the reactions of alkali metals with water" among the most favorites. We just happened ...
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1answer
183 views

Why and how does lycopene absorbance increase with heating?

Lycopene, which is a carotenoid and a phytochemical is the main reason for why tomatoes are radio-protective. Source 1 . Source 2 Let's cut to the chase: I was wondering if this claim of The ...