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maksim [4K]
3 years ago
9

Nuclear decay occurs according to first-order kinetics. Cobalt-60 decays with a rate constant of 0.131 years−1. After 5.00 years

, a sample has a mass of 0.302 g. What was the original mass of the sample?
Physics
1 answer:
alexandr402 [8]3 years ago
8 0

Answer : The original mass of the sample was 0.581 grams.

Explanation :

Expression for rate law for first order kinetics is given by:

t=\frac{2.303}{k}\log\frac{a}{a-x}

where,

k = rate constant  = 0.131\text{ years}^{-1}

t = time passed by the sample = 5.00 years

a = original or initial amount of the reactant  = ?

a - x = amount left after decay process = 0.302 g

Now put all the given values in above equation, we get

5.00\text{ years}=\frac{2.303}{0.131\text{ years}^{-1}}\log\frac{a}{0.302g}

a=0.581g

Therefore, the original mass of the sample was 0.581 grams.

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Answer:

The solution(s) are in order with respect to the attachments

2.613\:\cdot10^5 Joules ; 5. Adding the same amount of heat to two different objects will produce the same increase in temperature ; 2. Same speed in both ; 2. A

Explanation:

Diagram 1 ( Liquid Nitrogen ) : So as you can see, we want our units in Joules here, and can therefore multiply the mass of gaseous nitrogen and the latent heat of liquid nitrogen, to cancel the units kg, and receive our solution - in terms of Joules. Let's do it.

q ( energy removed ) = mass of nitrogen * latent heat of liquid nitrogen,

q = 1.3 kg * 2.01 * 10⁵ J / kg = 1.3\:\cdot \:2.01\:\cdot \:\:10^5 = 10^5\cdot \:2.613 = 100000\cdot \:2.613 = 261300 Joules = 261.3 kiloJoules = 2.613 * 10⁵Joules is the energy that must be removed

Diagram 2 : The same amount of heat does not necessarily mean the same increase in temperature for two different objects. The increase in temperature depends on the specific heat capacity of the substance. Therefore your solution is 5 ) Adding the same amount of heat to two different objects will produce the same increase in temperature.

Diagram 3 : The temperatures in both glasses are the same, and hence the molecules have the same average speed. Therefore your solution is 2 ) Same speed in both.

Diagram 4 : Glass A has more water molecules, and hence has more thermal energy. Your solution is 2 ) A.

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3 years ago
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Which of the following is NOT one of the four elements of emotion?
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Answer:

Attention

Explanation:

Hello there, fellow peer! The answer to question is attention. Let's say someone is the control. The behavioral expression is an element of expression, so the control will feel emotions. Subjective Experience is when someone felt the way you feel and they are trying to help you. That is a type of emotion which can lead to empathy for you. This is also not the answer. Physiological Arousal is also not the answer because this is when you can feel what someone else is feeling and you try to give them therapy.

Using the process of elimination, our answer is therefore attention.

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A 1.2 KG rubber ball is being thrown in the air if the ball is traveling at 2.0 M/S when it is 3.0 M off the ground what is the
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Answer:

b. 3 times

Explanation:

Lets take

Coefficient for ordinary glass = α₁

Coefficient for pyrex glass = α₂

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Initial length of both glasses are equal = L

Change in the temperature is also same .= ΔT

We know that change in the length  given as

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Therefore

\dfrac{\Delta L_1}{\Delta L_2}=\dfrac{L\alpha_1\Delta T}{L\alpha_2\Delta T}

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Therefore change in the length of original glass is three time of pyrex glass.

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