Answer:
NaCl
Explanation:
because He which is helium gas its an element alone,
Cl which is chlorine is a single element,
B which is Boron and its a single element,
but NaCl which is simply called table sugar is the combination between Na, sodium and Cl, chlorine , so its called a compound not an element.
The answer is Na < Cl
Chlorine is more electronegative than sodium because this follows the trend of the periodic table. The trend states that an element's electronegativity increases from left to right of a period and bottom to up of a group. Since sodium and chlorine are from the same period, and chlorine is at the right of sodium, chlorine is more electronegative.
If an athlete has X joules of mechanical energy at the top of the hill, he will have the same X amount of energy at the bottom of the hill.
<h3>What is mechanical energy?</h3>
Mechanical energy is the addition of kinetic and potential energy. It can be either kinetic or potential energy.
It is the energy possessed by the position or the motion of the body.
It is the energy present to perform any work.
So, the athlete will have X joule of energy at the top and bottom of the hill.
Thus, the correct option is a, X joules.
Learn more about mechanical energy
brainly.com/question/20030300
Option C is the correct set of the problem for mass of water produced by 3.2 moles of oxygen and an excess ethene.
<h3>
Reaction between oxygen and ethene</h3>
Ethene (C2H4) burns in the presence of oxygen (O2) to form carbon dioxide (CO2) and water (H2O) along with the evolution of heat and light.
C₂H₄ + 3O₂ ----- > 2CO₂ + 2H₂O
from the equation above;
3 moles of O₂ ---------> 2(18 g) of water
3.5 moles of O₂ ----------> x
![x = 3.2 \times [\frac{2 \ moles \ H_2O}{3 \ moles \ O_2} ] \times[ \frac{18.02 \ g \ H_2O}{1 \ mole \ H_2O} ]](https://tex.z-dn.net/?f=x%20%3D%203.2%20%5Ctimes%20%5B%5Cfrac%7B2%20%5C%20moles%20%5C%20H_2O%7D%7B3%20%5C%20moles%20%5C%20O_2%7D%20%20%5D%20%5Ctimes%5B%20%5Cfrac%7B18.02%20%5C%20g%20%5C%20H_2O%7D%7B1%20%5C%20mole%20%5C%20H_2O%7D%20%5D)
Thus, option C is the correct set of the problem for mass of water produced by 3.2 moles of oxygen and an excess ethene.
Learn more about reaction of ethene here: brainly.com/question/4282233
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