What is the element with the lowest electronegativity value? A. Cesium B. Helium C. Calcium D. Fluorine

a rock is examined to determine its age, and the ratio of uranium-235 to lead-207 is found to be 125,000:875,000. the half-life

slamgirl [31]

The old age of rock when examined is 21.4 million years if the ratio of uranium-235 to lead-207 is found to be 125,000:875,000. the half-life of uranium-235 is 700 million years.

<h3>Decaying Equation </h3>

P = [P + D] (1/2) ^(t/t(1/2))

where,

P represent the present parent amount

D is the present daughter amount

t(1/2) is the half life time period

t is the actual age

We know that,

t = (log[(P+D) /P] / log2) × t(1/2) ----------(1)

Given,

P = 97.6

D = 2.1

Ratio of P and D can be calculated as

P/D = 97.6/2.1

= 46.476

By substituting all the values in eq(1), we get

t = [(log 46.476 +1)/log2] × t(1/2)

Given,

The half life of U —Pb decay is 700 million years.

So,

t = [(log 46.476 +1)/log2] × 700

t = 21.4 million years.

Thus, we calculated that the the old age of rock when examined is 21.4 million years.

learn more about Half life period:

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DISCLAIMER:

The given question is misprint on portal.

Here is the correct form of question:

A rock is examined to determine its age, and the ratio of uranium-235 to lead-207 is found to be 125,000:875,000. the half-life of uranium-235 is 700 million years.

How old is the rock if it contains Uranium-235/ lead-207 ratio of 97.6 to 2.1?

8 0

2 years ago

What occurs in photosynthesis reaction

marusya05 [52]

Answer and Explanation:

Photosynthesis reaction involves two reactants, carbon dioxide and water. These two reactants yield two products, namely, oxygen and glucose.

6 0

3 years ago

What are 4 other gases in the atmosphere besides oxegen and nitergin?

Levart [38]

Helium, neon,nitrogen and argon

5 0

3 years ago

Predict the products of the reaction below. that is, complete the right-hand side of the chemical equation. be sure your equatio

kkurt [141]

The equation is as follow,

 HBr ₍aq₎ + H₂O ₍l₎ →

Solution:
HBr being strong acid with Ka value of 1.0 × 10⁹. When HBr is added to water, water acts as a base and HBr acts as a acid. Water picks the proton (H⁺) from HBr and converts into Conjugate acid (H₃O⁺) ahile HBr is converted into Conjugate Base (Br⁻) after loosing proton. The equation for this reaction is as follow,

HBr ₍aq₎ + H₂O ₍l₎ → H₃O⁺ ₍aq₎ + Br⁻ ₍aq₎

8 0

4 years ago

The formula of nitrogen oxide is NO, of nitrogen dioxide is NO_2. Write a balanced equation for the reaction of nitrogen oxide w

denis23 [38]

Answer:

a) 0,5 mol O₂; 1 mol NO₂

b)

Liters of NO = 22,4 L

Liters of O₂ = 11,2 L

Liters of NO₂ = 22,4 L

c) NO = 30g

O₂ = 16g

NO₂ = 46g

d) 7,41g HCl

e) 107,7 g/mol

f) 0,0312 moles of O₂; 0,999g of O₂; 699 mL at STP or 803 mL

ii. 51%

g) 32,6L

Explanation:

a) For the reaction:

2 NO + O₂ → 2 NO₂

For 1 mole of NO there are consumed:

1 mol NO × $\frac{1molO_{2}}{2molNO}$ = 0,5 mol of O₂

And produced:

1 mol NO × $\frac{2molNO_{2}}{2molNO}$ = 1 mol of NO₂

b) By ideal gas law:

V = nRT/P

Where n is moles of each compound; R is gas constant (0,082atmL/molK); T is temperature (273,15 K at state conditions); P is pressure (1 atm at STP) and V is volume in liters. Replacing each moles for each compound:

Liters of NO = 22,4 L

Liters of O₂ = 11,2 L

Liters of NO₂ = 22,4 L

c) The mass of each compound are:

1 mol NO× $\frac{30 g}{1molNO}$ = 30g