Answer:
We show added energy to a system as +Q or -W
Explanation:
The first law of thermodynamics states that, in an isolated system, energy can neither be created nor be destroyed;
Energy is added to the internal energy of a system as either work energy or heat energy as follows;
ΔU = Q - W
Therefore, when energy is added as heat energy to a system, we show the energy as positive Q (+Q), when energy is added to the system in the form of work, we show the energy as minus W (-W).
Answer: A. need the same number of electrons to fill their valence shells
B. have the same number of valence electrons
Explanation:
Elements are distributed in groups and periods in a periodic table.
Elements that belong to same groups will show similar chemical properties because they have same number of valence electrons.
Example: Flourine, chlorine and bromine are elements which belong to Group 17. They have 9, 17 and 35 electrons respectively and contain 7 valence electrons each and need one electron to complete their octet.
The chemical reactivity of elements is governed by the valence electrons present in the element.
![F:9:1s^22s^22p^5](https://tex.z-dn.net/?f=F%3A9%3A1s%5E22s%5E22p%5E5)
![Cl:17:1s^22s^22p^63s^23p^5](https://tex.z-dn.net/?f=Cl%3A17%3A1s%5E22s%5E22p%5E63s%5E23p%5E5)
![Br:35:1s^22s^22p^63s^23p^63d^{10}4s^24p^5](https://tex.z-dn.net/?f=Br%3A35%3A1s%5E22s%5E22p%5E63s%5E23p%5E63d%5E%7B10%7D4s%5E24p%5E5)
False.
Theories are hypotheses that have been shown to accurately and predictably explain results obtained through repeated experimentation, to the point where the hypothesis can be assumed to be true. Then, such a hypothesis would be considered a theory.
Answer:
0.0083km or 8.3m
Explanation:
Given parameters:
Distance = 5km
Time = 10min
Unknown:
Distance moved in 1sec = ?
Solution:
To solve this problem, let us first find the speed of the motorbike.
Speed =
Speed =
= 0.5km/min
So;
In 1sec:
60 sec = 1 min
1 sec =
min
Distance moved in 1sec = speed x time
Distance moved = 0.5km/min x
min = 0.0083km or 8.3m