What is a radioactive idotope?

Explanation:

Let's analyze the statements one by one:

a) This process is exothermic.

True. The negative enthalpy change (-2,021 kJ) indicates that heat is released during the reaction, making it exothermic.

b) The enthalpy change for 2C₃H₇OH(l)+9O₂(g)→6CO₂(g)+8H₂O(l) is 2,021 kJ.

False. The balanced chemical equation and enthalpy change given are for the combustion of 1 mole of propanol, not 2 moles.

c) The enthalpy change for 2C₃H₇OH(l)+9O₂(g)→6CO₂(g)+8H₂O(l) is -4,042 kJ.

False. This statement suggests a doubled enthalpy change value in the wrong direction. The correct direction is negative (exothermic), but the magnitude is not doubled.

d) The enthalpy change for 2C₃H₇OH(l)+9O₂(g)→6CO₂(g)+8H₂O(l) is -2,021 kJ.

False. This statement suggests the correct direction but doubles the magnitude. The correct magnitude is -2,021 kJ for 1 mole of propanol.

e) This chemical process transfers heat from the surroundings to the system.

False. The process is exothermic, which means it releases heat from the system to the surroundings.

f) The enthalpy change for 2C₃H₇OH(l)+9O₂(g)→6CO₂(g)+8H₂O(l) is 4,042 kJ.

False. This statement suggests the correct magnitude but in the wrong direction. The correct direction is negative (exothermic).

g) This process is endothermic.

False. The process is exothermic, as indicated by the negative enthalpy change.

h) This chemical process transfers heat from the system to the surroundings.

True. An exothermic process like this releases heat from the system to the surroundings.

So, the correct statements are:

a) This process is exothermic.

e) This chemical process transfers heat from the surroundings to the system.

h) This chemical process transfers heat from the system to the surroundings.

Final answer:

The breaking of the chemical bond between the second and third phosphates of ATP (Adenosine triphosphate) releases significant energy, transforming ATP into adenosine diphosphate (ADP) and an inorganic phosphate group. The energy released powers various biological processes and reactions within cells. This cycle of breaking and reforming ATP, often referred to as hydrolysis, is crucial to cellular function.

Explanation:

Adenosine triphosphate (ATP) is a high-energy molecule that powers cellular processes. When the chemical bond between the second and third (or beta and gamma) phosphates of ATP is broken, it releases significant energy. This reaction, known as hydrolysis, transforms ATP into adenosine diphosphate (ADP) and an inorganic phosphate group (P;), both of which have lower free energy than the reactants. Here is the specific reaction: ATP + H₂O → ADP + P¡ + free energy.

The breaking of phosphates' strong bonds (phosphoanhydride bonds) releases enough energy to power various cellular reactions and processes. These bonds are considered 'high-energy' due to the amount of energy they release upon breaking.

This continuous cycle of ATP breaking down into ADP and phosphate, followed by their recombination, effectively powers the life processes within cells.

Learn more about Hydrolysis here:

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The statement that is true about semi conductors is this: A MATERIAL IS CLASSIFIED AS A SEMI CONDUCTOR IF ITS RESISTANCE TO THE FLOW OF ELECTRIC CURRENT IS TOO LOW TO PERMIT IT TO BE CALLED A CONDUCTOR.

Semi conductors refers to those materials that can conductor electricity only under suitable conditions, their resistance to the flow of electricity lies between that of conductors and non conductors. Semi conductors are usually used in some electric circuits because the flow of electricity through them can easily be controlled. Examples of semi conductors are silicon, germanium and selenium.

Answer:

B

Explanation:

Reactants are the compounds which reaction produce the products. In general terms this can be expressed symbolically as follows:

reactants -> products

Other phenomena like heat are omitted because are not always present, that is, only compounds are included. Therefore, in this reaction the reactants are C3H8 (propane) and O2 ( oxygen) and the products are CO2 (carbon dioxide) and H2O (water)

Answer:

Explanation:

Balancing Carbon atoms on the right side,

Balancing Hydrogen atoms on the right side,

Balancing Oxygen atoms on the left side,

The reactants are on the left side of the reaction:

Propane and oxygen are the reactants.

The products are on the right side of the reaction:

Carbon dioxide and water are the products.

1. Answer;

a. the strong nuclear force is much greater than the electric force.

Explanation;

• For an atom to be stable it means it has enough amount of binding energy to hold its nucleus together permanently.
• Therefore, an unstable atom lacks enough amount of binding energy to hold its nucleus permanently and thus undergoes decay to achieve stability. Unstable atoms are therefore referred to being radioactive.
• Small atoms are stable; this is because they have equal number of protons and neutrons and thus the protons and neutrons fill up energy levels while maximizing the strong force binding the nucleus together.

9. Answer;

b. change into a different element altogether.

Uranium-238 undergoes alpha decay. Therefore, uranium-238 will  change into a different element altogether.

Explanation;

• Unstable atoms undergo radioactive decay in order to achieve stability of their nucleus.
• Uranium-238 is an example of such atom, which may undergo decay to achieve stability.
• Alpha decay is one of the types of decays, others being beta decay and gamma decay. In alpha decay the radioactive isotope undergoes decay such that its mass number is decreased by four and its atomic number is decreased by two.
• Therefore, Uranium-238 undergoes alpha decay to form a different element whose mass number is 234 and atomic number is 90, known as thorium-234.