In 1982, the United States government changed the way it minted pennies. Before 1982, pennies were made of 95% copper and 5% tin. Now they are made of 97.5% zinc coated with copper. Because they weigh different amounts (have different masses) and are still the same item, they make a good model for studying isotopes.
4. What do the two kinds of pennies represent in this exercise?
5. How do the pennies differ? How do isotopes differ?
6. What do the pennies have in common? What do isotopes have in common?

Answers

Answer 1
you just do ok? boomer

Related Questions

Substitute natural gas (SNG) is a gaseous mixture containing CH4(g) that can be used as a fuel. One reaction for the production of SNG is
4CO(g) + 8H2(g) → 3CH4(g) + CO2(g) + 2H2O(l) ΔHo = ?

Use appropriate data from the following list to determine ΔHo for this SNG reaction.
C(graphite) + 1/2O2(g) → CO(g) ΔHo = -110.5 kJ
CO(g) + 1/2O2(g) → CO2(g) ΔHo = -283.0 kJ
H2(g) + 1/2O2(g) → H2O(l) ΔHo = -285.8 kJ
C(graphite) + 2H2(g) → CH4(g) ΔHo = -74.81 kJ
CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) ΔHo = -890.3 kJ

Answers

Answer:

ΔH° of the reaction is -747.54kJ

Explanation:

Based on gas law, it is possible to find the ΔH of a reaction using ΔH of half reactions.

Using the reactions:

(1) C(graphite) + 1/2O₂(g) → CO(g) ΔH° = -110.5 kJ

(2) CO(g) + 1/2O₂(g) → CO₂(g) ΔH° = -283.0 kJ

(3) H₂(g) + 1/2O₂(g) → H₂O(l) ΔH° = -285.8 kJ

(4) C(graphite) + 2H₂(g) → CH₄(g) ΔH° = -74.81 kJ

(5) CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l) ΔH° = -890.3 kJ

The sum of 4×(4) + (5) gives:

4C(graphite) + 8H₂(g) + 2O₂(g) → CO₂(g) + 2H₂O(l) + 3CH₄(g)

ΔH° = -74.81 kJ ×4 - 890.3 kJ = -1189.54kJ

Now, this reaction - 4×(1) gives:

4CO(g) + 8H₂(g) → CO₂(g) + 2H₂O(l) + 3CH₄(g)

ΔH° = -1189.54kJ - 4×-110.5 = -747.54kJ

Thus ΔH° of the reaction is -747.54kJ

ΔH° of the reaction is for the production of SNG -747.54kJ

Hess law and enthalpy

According to Hess’ law of constant summation, the standard reaction enthalpy is independent of the pathway or number of the reaction steps taken for a multistep reaction, rather it is the sum of standard enthalpies of intermediate reactions involved at the same temperature.

Based on Hess law, it is possible to find the ΔH of a reaction using ΔH of half reactions.

From the given reactions:

C(graphite) + 1/2O₂(g) → CO(g) ΔH° = -110.5 kJCO(g) + 1/2O₂(g) → CO₂(g) ΔH° = -283.0 kJH₂(g) + 1/2O₂(g) → H₂O(l) ΔH° = -285.8 kJC(graphite) + 2H₂(g) → CH₄(g) ΔH° = -74.81 kJCH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l) ΔH° = -890.3 kJ

The sum of Reaction 4 × 4 + Reaction 5 - Reaction 1 × 4 gives the reaction below:

4CO(g) + 8H₂(g) → CO₂(g) + 2H₂O(l) + 3CH₄(g)

ΔH° = {-74.81 kJ × 4} - 890.3 kJ {- 4 ×-110.5}

ΔH° = -747.54kJ

Therefore, ΔH° of the reaction is for the production of SNG -747.54kJ

Learn more about enthalpy and Hess' law at: https://brainly.com/question/9328637

What is the decay mode of radium-226?

Answers

Answer:

Radium-226 is a radioactive decay product in the uranium-238 decay series and is the precursor of radon-222. Radium-228 is a radioactive decay product in the thorium-232 decay series. Both isotopes give rise to many additional short-lived radionuclides, resulting in a wide spectrum of alpha, beta and gamma radiations.

If you wanted to perform a controlled experiment to test the effect of temperature on the pressure of a bicycle tire, which of the following would be necessary?

Answers

It would be the needle pressure gage temp check
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