Answer:
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Explanation:
The changes in temperature caused by a reaction, combined with the values of the specific heat and the mass of the reacting system, makes it possible to determine the heat of reaction.
Heat energy can be measured by observing how the temperature of a known mass of water (or other substance) changes when heat is added or removed. This is basically how most heats of reaction are determined. The reaction is carried out in some insulated container, where the heat absorbed or evolved by the reaction causes the temperature of the contents to change. This temperature change is measured and the amount of heat that caused the change is calculated by multiplying the temperature change by the heat capacity of the system.
The apparatus used to measure the temperature change for a reacting system is called a calorimeter (that is, a calorie meter). The science of using such a device and the data obtained with it is called calorimetry. The design of a calorimeter is not standard and different calorimeters are used for the amount of precision required. One very simple design used in many general chemistry labs is the styrofoam "coffee cup" calorimeter, which usually consists of two nested styrofoam cups.
When a reaction occurs at constant pressure inside a Styrofoam coffee-cup calorimeter, the enthalpy change involves heat, and little heat is lost to the lab (or gained from it). If the reaction evolves heat, for example, very nearly all of it stays inside the calorimeter, the amount of heat absorbed or evolved by the reaction is calculated.
First, consider the steps to heat the sample from 209 K to 367K.
1) Heating in liquid state from 209 K to 239.82 K
2) Vaporaizing at 239.82 K
3) Heating in gaseous state from 239.82 K to 367 K.
Second, calculate the amount of heat required for each step.
1) Liquid heating
Ammonia = NH3 => molar mass = 14.0 g/mol + 3*1g/mol = 17g/mol
=> number of moles = 12.62 g / 17 g/mol = 0.742 mol
Heat1 = #moles * heat capacity * ΔT
Heat1 = 0.742 mol * 80.8 J/mol*K * (239.82K - 209K) = 1,847.77 J
2) Vaporization
Heat2 = # moles * H vap
Heat2 = 0.742 mol * 23.33 kJ/mol = 17.31 kJ = 17310 J
3) Vapor heating
Heat3 = #moles * heat capacity * ΔT
Heat3 = 0.742 mol * 35.06 J / (mol*K) * (367K - 239.82K) = 3,308.53 J
Third, add up the heats for every steps:
Total heat = 1,847.77 J + 17,310 J + 3,308.53 J = 22,466.3 J
Fourth, divide the total heat by the heat rate:
Time = 22,466.3 J / (6000.0 J/min) = 3.7 min
Answer: 3.7 min
Answer:
Answers
1.)reactants: nitrogen and hydrogen; product: ammonia.
2.)reactants: magnesium hydroxide and nitric acid; products: magnesium nitrate and water.
3.)N 2 + 3H 2 → 2NH 3
4.)Mg(OH) 2 + 2HNO 3 → Mg(NO 3) 2 + 2H 2O.
5.)2NaClO 3 → 2NaCl + 3O 2
6.)4Al + 3O 2 → 2Al 2O 3
7.)N 2(g) + 3H 2(g) → 2NH 3(g)
Explanation:
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I believe the answer is Canada!
If you were to take water (like many other materials) and break it up into almost the smallest things you could, you’d get molecules. If the molecules are stuck together really tightly in a regular pattern, then they’re called a solid. The solid form of water is ice. This actually makes a lot of sense, because it certainly does seem like all the little parts of a solid (like ice) are stuck together very tightly.
When you heat something up, it makes the molecules move faster. If you heat up a typical solid, it melts and becomes a liquid. In a liquid (like water), the molecules are still stuck together, but they can move around some. What actually happens is that the molecules are still sort of sticking together, but they’re constantly breaking apart and sticking to different molecules. This also makes sense when you think about water. Water sort of sticks together, but it breaks apart /really/ easily.
If you heat a liquid like water up even more (like if you put it in a pot on the stove), then the molecules will move around so fast that they can’t even hold on to each other at all. When this happens, all of the molecules go flying apart and become a gas (like when you boil water to make steam). The process of gas molecules leaving the liquid to go into the gas is called "evaporation." The opposite process is called "condensation."
<span>Hope this answers your question!</span>
