Answer:
In a voltaic cell (one that happens spontaneously), electrons flow from a negative electrode to a positive electrode (anode cathode). The reaction that happens is a redox reaction where the anode is oxidized (goes from a solid to an ion) and the cathode is reduced (going from an ion to a solid).
Explanation:
Answer:
T = 215.33 °C
Explanation:
The activation energy is given by the Arrhenius equation:

<u>Where:</u>
k: is the rate constant
A: is the frequency factor
Ea: is the activation energy
R: is the gas constant = 8.314 J/(K*mol)
T: is the temperature
We have for the uncatalyzed reaction:
Ea₁ = 70 kJ/mol
And for the catalyzed reaction:
Ea₂ = 42 kJ/mol
T₂ = 20 °C = 293 K
The frequency factor A is constant and the initial concentrations are the same.
Since the rate of the uncatalyzed reaction (k₁) is equal to the rate of the catalyzed reaction (k₂), we have:

(1)
By solving equation (1) for T₁ we have:
Therefore, we need to heat the solution at 215.33 °C so that the rate of the uncatalyzed reaction is equal to the rate of the catalyzed reaction.
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Radioactive isotopes eventually decay, or disintegrate, to harmless materials. Some isotopes decay in hours or even minutes, but others decay very slowly. Strontium-90 and cesium-137 have half-lives of about 30 years (half the radioactivity will decay in 30 years). <u>Plutonium-239 has a half-life of 24,000 years.</u>
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<h3>What is radioactive decay? </h3>
Radioactive decay is the emission of energy in the form of ionizing radiation. The ionizing radiation that is emitted can include alpha particles, beta particles and/or gamma rays. Radioactive decay occurs in unbalanced atoms called radionuclides.
Elements in the periodic table can take on several forms. Some of these forms are stable; other forms are unstable. Typically, the most stable form of an element is the most common in nature. However, all elements have an unstable form. Unstable forms emit ionizing radiation and are radioactive. There are some elements with no stable form that are always radioactive, such as uranium. Elements that emit ionizing radiation are called radionuclides.
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Answer:

Explanation:
Hello,
In this case, since in a dilution process the moles of the solute must remain unchanged, we use the volumes and molarities as shown below:

Clearly, the concentrated solution is 12M and the diluted solution is 0.5 M, thus, the volume of the concentrated solution we should take is:

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After heating the brick and the iron, it is observed that the brick heats up quicker and the brick releases energy quicker.
<h3>What is thermal energy?</h3>
Thermal energy (also called heat energy) is produced when a rise in temperature causes atoms and molecules to move faster and collide with each other.
The iron has more energy than the brick even though it is at the same temperature. That means that the iron must have more particles than the brick.
Iron and brick are both solids and have the same volume, so the difference in total energy must be due to atomic composition.
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