What is the definition of half-life
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Answer:
the time taken for the radioactivity of a specified isotope to fall to half its original value.
Explanation:
Related Questions
Two liquids mix, neither absorbing nor releasing heat.
Select the CORRECT pairing. A. pasteurization: low temperatures, long periods of time B. filtration : pore sizes less than 0.45 micrometers C. desiccation : lowering the pH D. cooling: high temperatures, short period of time
Fter a radioactive atom decays, it is the same element that it was before with no measurable change in mass. Which kind of decay has occurred, and how do you know?
A period is a horizontal row on the periodic table. a. True b. False
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This is because aluminium has a 3+ charge and nitrate has a 1- charge, so you need 3 of them to balance out aluminium.
Therefore, you have one ion of aluminium.
a neutralization reaction
a reaction in which oxidation numbers change
a reaction in which no electrons are transferred.
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A reaction where oxidation numbers change.
A reduction is when electrons are gained while oxidation is when electrons are lost.
endothermic, causing an increase in the kinetic energy of the water molecules.
(exothermic, causing an increase in the kinetic energy of the water molecules.)
exothermic, causing an increase in the kinetic energy of the solute particles.
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The reaction is exothermic, causing an increase in the kinetic energy of the water molecules.
• In a calorimeter when the reaction takes place, and there is an increase in temperature recorded in the thermometer, it shows that the reaction is emitting heat to the surrounding, and such kind of reactions is known as exothermic reaction.
• With the mixing of aqueous solution of HCl and NaOH the temperature of the solution increases, this shows that the kinetic energy of the water molecules increases. As, kinetic energy is directly proportional to the temperature.
• With increase in temperature, the collision or vibration of molecules increases, thus, there is an increase in the kinetic energy between the molecules.
Thus, the reaction is exothermic, causing an increase in the kinetic energy of the water molecules.
To know more about:
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Answer:
Mass percent of N2H4 in original gaseous mixture = 31.13 %
Explanation:
Given:
Initial mass of gaseous mixture = 61.00 g
Initial mole of oxygen = 10.0 mol
Moles of oxygen remaining after the reaction = 4.062 mol
Moles of oxygen used = 10.0 - 4.062 = 5.938 mol
Total oxygen used in both the reactions = 10.0 parts
out of 10 parts, 3 part react with N2H4.
Now, consider the reaction of N2H4
3 moles of O2 react with 1 mole of N2H4
1.78 moles of oxygen will react with 1.78/3 = 0.5933 mol of N2H4
Molecular mass of N2H4 = 32 g/mol
Total mass = 61.0 g
Final answer:
The mass percent of N2H4 in the gaseous mixture can be determined through stoichiometric calculations and determining the limiting reactant. The initial and remaining amounts of O2 are used to calculate the reacted amount of O2, which then allows for the calculation of the amount of N2H4. This information is used in the mass percent formula.
Explanation:
The balanced reaction states that for one mole of NH3, one mole of O2 is required, while for one mole of N2H4, 3 moles of O2 are required. Thus, the initial moles of O2 were 10 moles and after reaction 4.062 moles O2 remained. Thus, the reacted amount of O2 is 10 - 4.062 = 5.938 moles. From calculating the limiting reactant and applying stoichiometry, the amount of N2H4 can be determined. We know the molar mass of N2H4 is 32 g/mole. By calculating the molar ratio, we can then calculate the mass percent of N2H4 in the mixture using the formula: (mass of N2H4 / total mass) * 100%.
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When a gas condenses to liquid the process is exothermic with the release energy and the enthalpy change is negative. As liquid has more ordered structure than gas, the entropy, which is the measure of disorder decreases or ∆ S has a negative value.
Free energy is given by the Gibb's free energy equation,
∆G = ∆H –T∆S
For a process to be spontaneous ∆ G must be negative.
∆H is negative and ∆S is negative, so the magnitude of |T∆S| should be less than the magnitude of |∆H| in that way ∆G is always negative.
|T∆S| should be less than the magnitude of |∆H|, so to favor that T should be low. The process is spontaneous at a lower temperature than at a higher temperature.
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Combining carbon and sulfur can result in compounds with various physical states at room temperature, such as solids (e.g., carbon disulfide) or gases (e.g., carbon dioxide). The state depends on the specific compound formed.
The type of chemical bonds and interactions that exist between a compound's components, as well as the temperature and pressure levels, all affect the compound's physical state.
While in their pure elemental forms, carbon and sulfur are both solid at ambient temperature, combining them to create a compound can produce a substance with a variety of qualities.
For instance, carbon and sulfur can combine to generate molecules like carbon disulfide, a volatile and extremely combustible liquid that exists at room temperature and at normal atmospheric pressure.
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