Exothermic<span>- the word describes a process that releases </span>energy<span> in the form of heat. Forming a chemical bond releases </span>energy<span> and therefore is an </span>exothermic<span> process. </span>Exothermic<span>reactions usually feel hot because it is giving heat to you. </span>Endothermic<span> - a process or reaction that absorbs </span>energy<span> in the form of heat.</span>
Answer:
A. The accepted model of the atom was changed.
Explanation:
Thomson described an atom that has the protons uniformly distributed within a circular atom with the electrons embedded . However, it cannot explain the emission of electrons from the surfaces of metals like photoelectric emission. it does not explain how the particle of the atom contribute significantly to the entire mass of an atom
Oxygen is the 2nd most electronegative element. When you examine a periodic table, you will find that (excluding the noble gases) the electronegativity values tend to increase as you go to the right and up. The reverse statement is that the values tend to decrease going down and to the left.
Answer: The correct answer is -297 kJ.
Explanation:
To solve this problem, we want to modify each of the equations given to get the equation at the bottom of the photo. To do this, we realize that we need SO2 on the right side of the equation (as a product). This lets us know that we must reverse the first equation. This gives us:
2SO3 —> O2 + 2SO2 (196 kJ)
Remember that we take the opposite of the enthalpy change (reverse the sign) when we reverse the equation.
Now, both equations have double the coefficients that we would like (for example, there is 2S in the second equation when we need only S). This means we should multiply each equation (and their enthalpy changes) by 1/2. This gives us:
SO3 —>1/2O2 + SO2 (98 kJ)
S + 3/2O2 —> SO3 (-395 kJ)
Now, we add the two equations together. Notice that the SO3 in the reactants in the first equation and the SO3 in the products of the second equation cancel. Also note that O2 is present on both sides of the equation, so we must subtract 3/2 - 1/2, giving us a net 1O2 on the left side of the equation.
S + O2 —> SO2
Now, we must add the enthalpies together to get our final answer.
-395 kJ + 98 kJ = -297 kJ
Hope this helps!
