Answer: "The reactants are higher in energy than the products"
Explanation:
The exothermic reactions are characterized by the release of heat to the surroundings. The reactants lose heat that is delivered to the surroundings which implies that the products will be lower in energy than the reactants.
The hills that you can see in a reaction energy diagram are not related with the final change of energy. The hills are an indication of the activation energy needed to start the reaction, but they do not measure the change of energy from the products to the reactants.
The enthalpy that is a state variable that identifies the content of heat. Then the change of enthalpy for the exothermic reactions is negative, meaning that the energy of the products is lower than the energy of the reactants.
Answer:
The hydroxide [OH-] concentration of the solution is 1.26*10⁻⁵ M.
Explanation:
The pOH (or potential OH) is a measure of the basicity or alkalinity of a solution.
POH indicates the concentration of hydroxyl ions [OH-] present in a solution and is defined as the negative logarithm of the activity of hydroxide ions (that is, the concentration of OH- ions):
pOH= -log [OH-]
A solution has a pOH of 4.90. Replacing in the definition of pOH:
4.90= -log [OH-]
Solving:
-4.90= log [OH-]
1.26*10⁻⁵ M= [OH-]
<u><em>The hydroxide [OH-] concentration of the solution is 1.26*10⁻⁵ M.</em></u>
Answer:
Wegener discovered that the Appalachian Mountains of the eastern United States, for instance, were geologically related to the Caledonian Mountains of Scotland. Pangaea existed about 240 million years ago. By about 200 million years ago, this supercontinent began breaking up
Lithium is one of element of group 1 of periodic table.
Lithium has the smallest radius than as compared to the other elements, thus the density of the alkali metal is also less.
Lithium when added to water it floats, because of lower density. It eventually fizzes and becomes smaller.
The reaction on lithium and water is:
2Li + 2H₂O --> 2LiOH + H₂ (g)
The hydrogen gas which is liberated is highly flammable.
Thus, lithium salts are insoluble in water.
Density is defined as the mass of a substance per unit volume.
Density = Mass ÷ Volume.
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To being my discussion, I claim that a new atomic model should always build on an old one with the following reasons of mine. That is option B.
<h3>What is an atomic model?</h3>
An atomic model is a model that describes how the interior of an atom looks like. This first atomic model was developed by William Thomson.
To start my discussion, I claim that a new atomic model should always build on an old one with the following reasons of mine:
- The modern scientists exploited the ideas of the ancient scientists to arrive at a better atomic model.
- This method is proven the the works of Bohr in the Bohr atomic model which relied on quantum mechanics, built upon the Rutherford model to explain the orbits of electrons.
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