If I understand this right, the two elements are Nickel and Copper, elements 28 and 28, respectively. A nickel is worth 5 cents, and a penny, originally comprised of copper, is worth one - the total being six cents.
Answer:

Explanation:
First, we find in the tables the ΔH of formation of each compound. As you can see in the (image 1)
Then we solve the ecuation for ΔH°reaction
ΔH°reaction=∑ΔH°f(products)−∑ΔH°f(Reactants)
ΔH°reaction= (-2* 393.5 - 2*285.8) - (52.4 + 0) kJ/mol
ΔH°reaction = -1.41 *10^3 kJ/mol
Answer:
Nitrogen and Oxygen make up 99% of the Earths atmosphere. Then Argon makes up the rest of the atmosphere.
Answer:
Explanatio(3) Atomic masses are a weighted average of the naturally occurring isotopes.
(3) Atomic masses are a weighted average of the naturally occurring isotopes. is the best statement for why most atomic masses on the Periodic Table are decimal numbers.
Answer: The independent variable is the type of metal being used.
{Note: The "dependent variable" is the "measured density" that corresponds to each of the metals."}.
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Explanation:
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The "independent variable", which is plotted on the "x-axis" (horizontal axis), is the variable that can be "controlled/manipulated". In this case, this would be the type of metal chosen.
The "dependent variable" , which is plotted on the "y-axis" (vertical axis) is the "obtained value/measurement/result" (that "cannot be controlled/manipulated").
In this case, the "density", which is the "measured value" that corresponds to the selected "meal", is the "dependent variable".
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Hope this helpful to you!
Wishing you well!
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