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Tamiku [17]
3 years ago
6

If a “sample” of pennies contained 75 heads and 25 tails, how many half‐lives would have passed since the “sample” formed. Expla

in your answer.
If a “sample” of pennies contained 25 heads and 75 tails, how many half‐lives would have passed since the “sample” formed. Explain your answer.

Please help, our teacher teaches nothing and we get random work with no context! This is the only question our whole (honors) class doesn't understand.
Chemistry
1 answer:
finlep [7]3 years ago
8 0
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Would be glad if you helped me!
Sindrei [870]
A) Fe⁰ ----> Fe⁺³ +3e⁻   oxidation        | *2
b) <u>Cu⁺² + 2e⁻ -----> Cu⁰  reduction      |*3</u>

c) 2Fe⁰ +3Cu⁺² -----> 2Fe⁺³ + 2Cu⁰
6 0
3 years ago
Compare and contrast the ease at which molecules are able to move relative to each other in the three states of matter
ANTONII [103]
The arrangement of molecules within the 3 phases of matter are shown in the picture. 

For the solid, the molecules are packed closely together. They don't have much space to move, so they just practically vibrate. For the liquid, the molecules are relatively farther from each other. The liquid molecules can flow freely but not as much as the gases. In the gases, the molecules are very far from each other. They are very sensitive to slight changes of pressure, volume and temperature.

5 0
3 years ago
Reaction rate is expressed in terms of changes in the concentration of reactants and products. Write a balanced equation for the
KengaRu [80]

Answer : The balanced equations will be:

CH_4+2O_2\rightarrow 2H_2O+CO_2

Explanation :

The general rate of reaction is,

aA+bB\rightarrow cC+dD

Rate of reaction : It is defined as the change in the concentration of any one of the reactants or products per unit time.

The expression for rate of reaction will be :

\text{Rate of disappearance of A}=-\frac{1}{a}\frac{d[A]}{dt}

\text{Rate of disappearance of B}=-\frac{1}{b}\frac{d[B]}{dt}

\text{Rate of formation of C}=+\frac{1}{c}\frac{d[C]}{dt}

\text{Rate of formation of D}=+\frac{1}{d}\frac{d[D]}{dt}

Rate=-\frac{1}{a}\frac{d[A]}{dt}=-\frac{1}{b}\frac{d[B]}{dt}=+\frac{1}{c}\frac{d[C]}{dt}=+\frac{1}{d}\frac{d[D]}{dt}

From this we conclude that,

In the rate of reaction, A and B are the reactants and C and D are the products.

a, b, c and d are the stoichiometric coefficient of A, B, C and D respectively.

The negative sign along with the reactant terms is used simply to show that the concentration of the reactant is decreasing and positive sign along with the product terms is used simply to show that the concentration of the product is increasing.

Now we have to determine the balanced equations corresponding to the following rate expressions.

Rate=-\frac{d[CH_4]}{dt}=-\frac{1}{2}\frac{d[O_2]}{dt}=+\frac{1}{2}\frac{d[H_2O]}{dt}=+\frac{d[CO_2]}{dt}

The balanced equations will be:

CH_4+2O_2\rightarrow 2H_2O+CO_2

5 0
3 years ago
Is there such thing as a pure mixture?
prisoha [69]
Pure substances are further broken down into elements and compounds. Mixture are physically combined structures that can be separated into their original components. A chemical substance is composed of one type of atom or molecule.
3 0
3 years ago
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What tools would you use to measure the density of a rectangular block?
dimulka [17.4K]
A scale and a ruler. The scale to measure the mass, and a ruler to measure the volume.
3 0
3 years ago
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