answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kvv77 [185]
2 years ago
8

Three radioisotopes are being discussed in a chemistry class. Technetium-99m has a half-life of 6 hours. Rubidium-87 has a half-

life of 50 billion years. Which describes who would most likely use each isotope? A geologist would use technetium-99m because short-life indicates an older organism, and a doctor would use rubidium-87 because it allows for a more-accurate measurement of disease.
A doctor would use technetium-99m because a short half-life indicates a quick measurement, and a geologist would use rubidium-87 because a longer half-life means that there is a longer time to measure old rock.
A doctor would use technetium-99m because a short half-life indicates a quick measurement, and an archeologist would use rubidium-87 because anything containing carbon also contains rubidium.
A geologist would use technetium-99m because a short half-life indicates an older organism, and an archeologist would use rubidium-87 because anything containing carbon also contains rubidium.
Chemistry
2 answers:
prohojiy [21]2 years ago
4 0

Answer:

A doctor would use technetium-99m because a short half-life indicates a quick measurement, and a geologist would use rubidium-87 because a longer half-life means that there is a longer time to measure old rock.

Explanation:

The radioisotopes are used to measure the presence of certain elements in molecules and in different substances, Technetium-99m has a short time of half life, 6 hours is good for doctors to measure the presence of that element in the human body or in another organisms, in the case of geologists, Rubidium-87, and its presence in certain rocks can make an impact on the presence and age of those rocks.

suter [353]2 years ago
3 0
B.)<span>A doctor would use technetium-99m because a short half-life indicates a quick measurement, and a geologist would use rubidium-87 because a longer half-life means that there is a longer time to measure old rock. </span>
You might be interested in
Methane, CH4, reacts with I2 according to the reaction CH4(g)+I2(g)⇌CH3I(g)+HI(g)
gtnhenbr [62]

Answer:

pCH₄ = 105.1 - 0.42 = 104.68 torr

pI₂ = 7.96 -0.42 = 7.54 torr

pCH₃I = 0.42 torr

pHI = 0.42 torr

Explanation:

Kp is the equilibrium constant for the partial pressure of the gases in the reaction, and it is calculated for a general equation:

aA(g) + bB(g) ⇄ cC(g) + dD(g)

Kp = \frac{(pC)^cx(pD)^d}{(pA)^ax(pB)^b}, where p is the partial pressure in the equilibrium. By the reaction given:

CH₄(g) + I₂(g) ⇄ CH₃I(g) + HI(g)

105.1 torr   7.96 torr  0       0            <em> initial partial pressure</em>

-x                  -x            +x     +x          <em> react</em>

105.1-x       7.96-x      x        x            <em>equilibrium</em>

Then:

Kp = \frac{pCH3IxpHI}{pCH4xpI2} = \frac{x^2}{(105.1-x)(7.96-x)}

2.26x10^{-4} = \frac{x^2}{836.596 - 113.06x -x^2}

x² = 0.1891 - 0.0255x -2.26x10⁻⁴x²

0.9997x² + 0.0255x - 0.1891 = 0

Using Bhaskara's rule:

Δ = (0.0255)² - 4x(0.9997)x(-0.1891)

Δ = 0.7568

x = \frac{-b+/-\sqrt{0.7568} }{2a} = \frac{-0.0255 +/-0.8699}{1.9994}

Using only the positive term, x = 0.42 torr.

So,

pCH₄ = 105.1 - 0.42 = 104.68 torr

pI₂ = 7.96 -0.42 = 7.54 torr

pCH₃I = 0.42 torr

pHI = 0.42 torr

8 0
2 years ago
Read 2 more answers
How many grams of calcium cyanide (Ca(CN)2) are contained in 0.79 mol of calcium cyanide?
Allushta [10]
I dont know but do you know da wae brudda?


3 0
2 years ago
Consider the chemical reaction: N2 3H2 yields 2NH3. If the concentration of the reactant H2 was increased from 1.0 x 10-2 M to 2
Brilliant_brown [7]

The equilibrium constant of a reaction is defined as:

"The ratio between equilibrium concentrations of products powered to their reaction quotient and  equilibrium concentration of reactants powered to thier reaction quotient".

The reaction quotient, Q, has the same algebraic expressions but use the actual concentrations of reactants.

To solve this question we need this additional information:

<em>For this reaction, K = 6.0x10⁻² and the initial concentrations of the reactants are:</em>

<em>[N₂] = 4.0M; [NH₃] = 1.0x10⁻⁴M and [H₂] = 1.0x10⁻²M</em>

<em />

Thus, for the reaction:

N₂ + 3H₂ ⇄ 2NH₃

The equilibrium constant, K, of this reaction, is defined as:

K = 6.0x10^{-2} = \frac{[NH_3]^2}{[N_2][H_2]^3}

And Q, is:

Q = \frac{[NH_3]^2}{[N_2][H_2]^3}

Where actual concentrations are:

[NH₃] = 1.0x10⁻⁴M

[N₂] = 4.0M

[H₂] = 2.5x10⁻¹M

Replacing:

Q = \frac{[1.0x10^{-4}]^2}{[4.0][2.5x10^{-1}]^3}

<h3>Q = 1.6x10⁻⁷</h3>

As Q < K,

<h3>The chemical system will shift to the right in order to produce more NH₃</h3>

Learn more about chemical equililbrium in:

brainly.com/question/24301138

8 0
2 years ago
Upon combustion, a 0.8009 g sample of a compound containing only carbon, hydrogen, and oxygen produces 1.6004 g co2 and 0.6551 g
dlinn [17]
The compound contains Carbon, Hydroxide and Oxide
1 mole of carbon iv oxide contains 44 g, out of which 12 g are carbon.
Therefore, 1.6004 g of CO2 will contain;
    1.6004 ×12/44 = 0.4365 g of carbon
1 mole of water contains 18 g of which 2 g is hydrogen,
Therefore, 0.6551 g of H2O will hace ;
         0.6551 × 2/18 = 0.0728 g of hydrogen.
The total mass of the compound is 0.8009 g,
Thus the mass of oxygen = 0.8009 -(0.4365 +0.0728)
                                         = 0.2916 g
To get the empirical formula we first get the number of moles of each element;\
 Carbon = 0.4365/12= 0.036375 moles
Hydrogen = 0.0728/1 = 0.0728 moles
Oxygen = 0.2916/16 = 0.018225 moles
Then, to get the smallest ratio we divide each with the smallest value;
Carbon :                        Hydrogen :                    Oxygen
= (0.036375/0.018225) : (0.0728/0.018225) : ( 0.018225/0.018225)
= 1.996                         :   3.995                    : 1
≈ 2 : 4 : 1
Therefore, the empirical formula is C2H4O


3 0
2 years ago
How many seconds are required to produce 4.00 g of aluminum metal from the electrolysis of molten alcl3 with an electrical curre
Brilliant_brown [7]
The correct answer is e. 3.57×10³
Al³+(aq) + 3e→AL(s)
4.00g of AL=4g/26.98 g/mol= 0.1483 mol
t=znF/1 where t is time in seceonds.
Z= valency number of ions of the substance or electrons which are transferred per ion
F= Faraday's constant
I = electric current in'A'CA  C/s
t=(3×0.1483 mol ×96485 C/mol) /12(C15)
t=3577 second = 3.5 ×10³s
8 0
2 years ago
Other questions:
  • How will the following changes affect the mole fraction of chlorine gas, χcl2, in the equilibrium mixture.?
    11·1 answer
  • If a sample of gas is at 672 °C and 3.9 atm, what is the new temperature at 12.2 atm?
    15·1 answer
  • A sample of a compound containing only carbon and oxygen decomposes and produces 24.50g of carbon and 32.59g of oxygen. what is
    5·2 answers
  • Chromium has an atomic mass of 51.9961 u51.9961 u and consists of four isotopes, Cr50,Cr50, Cr52,Cr52, Cr53,Cr53, and Cr54.Cr54.
    11·1 answer
  • C2H5OH(aq) + MnO− 4 (aq) → Mn2+(aq) + CH3COOH(aq) of acetic acid from ethanol by the action of permanganate ion in acidic soluti
    10·1 answer
  • 84. Heavy water, D2O (molar mass = 20.03 g mol–1), can be separated from ordinary water, H2O (molar mass = 18.01), as a result o
    10·1 answer
  • Hydrogen gas and bromine gas react to form hydrogen bromide gas. How much heat (kJ) is released when 155 grams of HBr is formed
    8·1 answer
  • A 1.555-g sample of baking soda decomposes with heat to produce 0.991 g Na2CO3. Refer to Example Exercise 14.l and show the calc
    10·1 answer
  • list down some examples of solutions that we need to prepare/make in the form of unsaturated and saturated solution​
    8·1 answer
  • An ideal gas occupies a volume V at an absolute temperature T. If the volume is halved and the pressure kept constant, what will
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!