Answer:
B. adding heat to the system and having the system do work on the surroundings
Explanation:
The internal energy of a system is the energy contained within the system. From first law of thermodynamics we have the equation : dq=du+dw
and we know that energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another therefore du is zero. dq = dw this means that the entire heat supplied is converted into work (on the surroundings)
However, some of the heat supplied is also used to increase the internal energy of the system
When a solid turns to gas it is called sublimation, and when a gas turns into a liquid it is called deposition
Answer : The percent by mass of the solution is 7.81 %
Explanation : Given,
Mass of NaCl = 8.75 g
Mass of solution = 112.0 g
Now we have to determine the percent by mass of the solution.
Putting values in above equation, we get:
Therefore, the percent by mass of the solution is 7.81 %
To find the mole of a substance, you take the mass divided by the molar mass of that substance~
First off chlorine is not a metal so you can ignore that one.
Sodium and Rubidium are in group 1 of the periodic table and Magnesium is in group 2.
Group one metals are more reactive than group two because it is harder for the group two metals to lose their 2 valence (outer most) electrons.
As you go down group 1 there is an increase in the reactivity this is because as you go down there is an increase in the atomic radius which leads to more shielding. This weakens the electrostatic forces of attraction making it easier to lose the outermost electrons, therefore they are more reactive.
