..x = 2 (bases are . Solve for x. a) 2* = 32 1 d) 5* = 625

Suppose you find a rock that contains 10 micrograms of radioactive potassium-40, which has a half-life of 1.25 billion years. By

attashe74 [19]

Answer:

The rock is 3.75 billion years ago.

Explanation:

Given that:

Half life = 1.25 billion years

1 billion years = 10⁹ years

So,

Half life = 1.25 × 10⁹ years

$t_{1/2}=\frac {ln\ 2}{k}$

Where, k is rate constant

So,

$k=\frac {ln\ 2}{t_{1/2}}$

$k=\frac {ln\ 2}{1.25\times 10^9}\ year^{-1}$

The rate constant, k = 5.5452 × 10⁻¹⁰ years⁻¹

Initial amount [A₀] = 80 micrograms

Final amount $[A_t]$ = 10 micrograms

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

So,

$10=80\times e^{-5.5452\times 10^{-10}\times t}$

$80e^{-5.5452\times \:10^{-10}x}=10$

$\frac{80e^{-5.5452\times \:10^{-10}x}}{80}=\frac{10}{80}$

$\ln \left(e^{-5.5452\times \:10^{-10}x}\right)=\ln \left(\frac{1}{8}\right)$

$x=\frac{10^{10}\times \:3\ln \left(2\right)}{5.5452}=3.75\times 10^9$

So,

The rock is 3.75 billion years ago.

8 0

3 years ago

"If Sam studies hard, he will do well in the class. Sam usually studies hard. So he will probably do well in the class." What is

Strike441 [17]

Answer: fairly high degree of commitment

Explanation: There are four levels of commitment. They are:

Distraction

Decision

Discipline

Devotion

A high level of commitment is really what is required to achieve major goals in life, and that brings us to the Commitment Scale.

Because Sam usually study hard, he has reached a high level of commitment through discipline and devotion. Definitely he will achieve his goal

6 0

3 years ago

Describe four different challenges facing refugees after they are allowed to entree a host country.

zubka84 [21]

The need for health care ,food supplies,shelter,clothing,jobs an possibly racism

Feeling isolated out of my element different cultures different beliefs a whole different way of life sometimes you have what's called a language barrier where you are not able to communicate with others due to not knowing the language spoken in the new country they reside in

5 0

3 years ago

Read 2 more answers

An individual is participating in illegal public demonstrations against fur dealers because he truly believes it is wrong to kil

drek231 [11]

Answer:

The stage represented is called the Post-Conventional

Explanation:

According to lawrence kohlberg's theory of moral development, the so-called post-conventional stage is one in which the individual determines in his subconscious what is right and wrong based on democratically pre-established social parameters. At this stage, laws are considered as social contracts rather than a strict commandment. The individual who is participating in illegal public demonstrations against fur traffickers believes it is wrong to kill animals to remove their fur, so we can conclude that it is at the Post-Conventional stage.

7 0

4 years ago

Who earned the nickname “The Wizard of Menlo Park”

Valentin [98]

Two of Edison's most famous inventions, the phonograph and the electric light system, were developed at Menlo Park. His accomplishments earned him the nickname the Wizard of Menlo Park.

7 0

4 years ago

Read 2 more answers

..x = 2 (bases are. Solve for x.a) 2* = 321d) 5* =625​

..x = 2 (bases are. Solve for x.a) 2* = 321d) 5* =625