Neon is a noble gas because it is stable non reactive and has ___

The half life for the radioactive decay of potassium- to argon- is years. Suppose nuclear chemical analysis shows that there is

Semmy [17]

Answer:

Therefore, the age of the rock sample is 2.7 * 10⁹ years

<em>Note: The question is missing some parts. The complete question is:</em>

<em>The half-life for the radioactive decay of potassium-40 to argon-40 is 1.26 * 10⁹ years. Suppose nuclear chemical analysis shows that there is 0.771 mmol of argon-40 for every 1.000 mmol of potassium-40 in a certain sample of rock. Calculate the age of the rock. Round your answer to significant digits.</em>

Explanation:

Half-life is defined as the amount of time it takes a given quantity to decrease to half of its initial value.

In radioactive isotopes of elements, the half-life is used to calculate the age of the materials in which the radioisotopes are found.

The half-life is related to the age of a material through the following formula:

t = t½㏑(Nt/N₀) / -㏑2

where t is the age of the material;

t½ is the half-life of the material

Nt is the amount of material left after time t

No is the starting amount of material

From the question:

t½ = 1.26 * 10⁹ years

Nt = 1.000 - 0.771 = 0.229

N₀ = 1.000

-㏑2 = -0.693

t = {1.26 * 10⁹ * ㏑(0.229)} / -0.693

t = 2.68 * 10⁹ which is approximately 2.7 * 10⁹ years to two significant digits.

Therefore, the age of the rock sample is 2.7 * 10⁹ years

8 0

2 years ago

Specify the steps included in the sedimentary rock formation

AlexFokin [52]

Answer:

Sedimentary rocks are the product of 1) weathering of preexisting rocks, 2) transport of the weathering products, 3) deposition of the material, followed by 4) compaction, and 5) cementation of the sediment to form a rock. The latter two steps are called lithification.

7 0

3 years ago

Be sure to answer all parts. What is the [H3O+] and the pH of a buffer that consists of 0.26 M HNO2 and 0.89 M KNO2? (K, of HNO2

Aleksandr-060686 [28]

Answer : The $H_3O^+$ ion concentration is, $1.12\times 10^{-3}M$ and the pH of a buffer is, 2.95

Explanation : Given,

$K_a=7.1\times 10^{-4}$

Concentration of $HNO_2$ (weak acid)= 0.26 M

Concentration of $KNO_2$ (conjugate base or salt)= 0.89 M

First we have to calculate the value of $pK_a$ .

The expression used for the calculation of $pK_a$ is,

$pK_a=-\log (K_a)$

Now put the value of $K_a$ in this expression, we get:

$pK_a=-\log (7.1\times 10^{-4})$

$pK_a=4-\log (7.1)$

$pK_a=3.15$

Now we have to calculate the pH of the solution.

Using Henderson Hesselbach equation :

$pH=pK_a+\log \frac{[Salt]}{[Acid]}$

$pH=pK_a+\log \frac{[KNO_2]}{[HNO_2]}$

Now put all the given values in this expression, we get:

$pH=3.15+\log (\frac{0.89}{0.26})$

$pH=2.95$

The pH of a buffer is, 2.95

Now we have to calculate the $H_3O^+$ ion concentration.

$pH=-\log [H_3O^+]$

$2.95=-\log [H_3O^+]$

$[H_3O^+]=1.12\times 10^{-3}M$

The $H_3O^+$ ion concentration is, $1.12\times 10^{-3}M$

4 0

3 years ago

Is there unlimited space in space?

Ahat [919]

I think so since in the universe there are other universes as well so maybe the might be even more space in space it is kind of confusing but it makes sense so yes the is space in space. Hope it helped pls give brainlyest

3 0

3 years ago

Read 2 more answers

20 POINTS!!!!

Ksju [112]

I think A. is the answer

5 0

3 years ago

Neon is a noble gas because it is stable non reactive and has ____ valence electrons