The atomic theory changed because as time passed by our technolgy has been improving our ability to find answers to these theories.
Dependent variables have to be in the experiment for it to work
independent variables do not.
When 1 mole of sodium chloride is mixed with 4 mole of magnesium chloride, the number of chloride ion present will be 5.4198 x 
molecules
<h3>Number of molecules in substances</h3>
1 mole of sodium chloride contains 1 mole of chloride ion according to the following equation:
NaCl ---> 
+ 
4 moles of magnesium chloride will contain moles of chloride ions according to the following equation:
The total number of moles of chloride ions in solution:
1+8 = 9 moles.
1 mole of a substance = 6.022 x 
Thus, the total number of chloride ions present in the mixture = 9 x 6.022 x
= 5.4198 x molecules
More on number of molecules in substances can be found here: brainly.com/question/11907018
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The potential energy diagram is a common way of depicting the reaction profile. The following are true about the diagram;
- The activation energy of the reaction is 35kJ.
- The enthalpy change of this reaction is 25kJ.
- The slope of the diagram is positive.
- The reaction is endothermic.
<h3>What is a potential energy diagram?</h3>
A potential energy diagram is a diagram that shows the conversion of reactants to products. It can tell us whether the reaction is endothermic or exothermic.
1) From the diagram, the activation energy of the reaction = 65 kJ - 30 kJ = 35 kJ
2) The enthalpy change of this reaction = 55kJ - 30 kJ = 25kJ.
3) The slope of the diagram is positive.
4) The reaction is endothermic.
Learn more about endothermic reaction:brainly.com/question/2192784
