1answer.
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
mafiozo [28]
3 years ago
15

If a 520 mg sample of technetium-99 is used for diagnostic procedure, how much of Tc-99 remains after 30.0h? Half life of Tc-99

is 6.0 hours.
Chemistry
1 answer:
k0ka [10]3 years ago
4 0
16.25 mg
I have attached an image of the half life formula.
In this problem, N0 would be 520, since that is the initial amount.
t = 30.0 Hours
t 1/2 = 6.0 hours
Now plug everything into the equation. You get 16.25 mg. No

You might be interested in
Use the periodic table to determine the electron configuration for iodine (i). express your answer in condensed form.
Dovator [93]
Iodine electron configuration is:

1S^2 2S^2 2P^6 3S^2 3P^6 4S^2 3d^10 4P^6 5S^2 4d^10  5P^5
when Krypton is the noble gas in the row above iodine in the periodic table,
we can change 1S^2  2S^2 2P^6 3S^2 3P^6 4S^2 3d^10 4P^6 by the symbol
[Kr] of Krypton.

So we can write the electron configuration of Iodine:
[Kr] 5S^2 4d^10 5P^5

8 0
3 years ago
Read 2 more answers
Anota una alternativa o solución que se pueda realizar para evitar la escasez de agua:
Olin [163]

Answer:

what??? ????????????????????

3 0
3 years ago
How many valence electrons are in an atom of magnesium?
dimulka [17.4K]
There are two valence electrons in a single atom of magnesium.
8 0
3 years ago
Read 2 more answers
A 2. 75-l container filled with co2 gas at 25°c and 225 kpa pressure springs a leak. When the container is re-sealed, the pressu
Serjik [45]

The number of moles of gas lost is  0.0213 mol. It can be solved with the help of Ideal gas law.

<h3>What is Ideal law ?</h3>

According to this law, "the volume of a given amount of gas is directly proportional to the number on moles of gas, directly proportional to the temperature and inversely proportional to the pressure. i.e.

PV = nRT.

Where,

  • p = pressure
  • V = volume (1.75 L = 1.75 x 10⁻³ m³)
  • T =  absolute temperature
  • n = number of moles
  • R =  gas constant, 8.314 J*(mol-K)

Therefore, the number of moles is

n = PV / RT

State 1 :

  • T₁ = (25⁰ C = 25+273 = 298 K)
  • p₁ = 225 kPa = 225 x 10³ N/m²

State 2 :

  • T₂ = 10 C = 283 K
  • p₂ = 185 kPa = 185 x 10³ N/m²

The loss in moles of gas from state 1 to state 2 is

Δn = V/R (P₁/T₁ - P₂/T₂ )

V/R = (1.75 x 10⁻³ m³)/(8.314 (N-m)/(mol-K) = 2.1049 x 10⁻⁴ (mol-m²-K)/N

p₁/T₁ = (225 x 10³)/298 = 755.0336 N/(m²-K)

p₂/T₂ = (185 x 10³)/283 = 653.7102 N/(m²-K)

Therefore,

Δn = (2.1049 x 10⁻⁴ (mol-m²-K)/N)*(755.0336 - 653.7102 N/(m²-K))

    = 0.0213 mol

Hence, The number of moles of gas lost is 0.0213 mol.

Learn more about ideal gas here ;

https://brainly.in/question/641453

#SPJ1

3 0
2 years ago
Iron has density 7.87 g/cm^3. if 52.4 g of iron is added to 75.0 mL of water in a graduated cylinder, to what volume reading wil
vlada-n [284]

Answer:

6.66 mL

Explanation:

The increase in the volume is due to the addition of the iron whose volume can be calculated as:

Using,

Density = Mass / Volume

Given that:

Density of Iron = 7.87 g/cm³

Mass of iron = 52.4 g

Thus, volume is:

Volume = Mass / Density = 52.4 / 7.87 cm³ = 6.66 cm³

Also, 1 cm³ = 1 mL

<u>The rise in the volume = 6.66 mL</u>

8 0
3 years ago
Other questions:
  • Which statement best describes how a salmon's tail fin helps it to survive?
    13·1 answer
  • Radiation _____. A. occurs in solids. B. occurs in liquids. C. requires physical contact between molecules. D. is the method of
    10·1 answer
  • Write balanced molecular equation for the reaction between nitric acid and calcium hydroxide. Express your answer as a chemical
    14·1 answer
  • The mineral magnesite contains magnesium carbonate, MgCO3 (molar mass= 84 g/mol), and other impurities. When a 1.26-g sample of
    9·2 answers
  • Chemical weathering processes do not alter the chemical structure of minerals in rocks. *
    10·1 answer
  • Helooo i need help please :)
    12·1 answer
  • How many bases are needed to code for one amino acid?
    12·1 answer
  • Which of the following best describe the chronological way of specimen preparation?
    9·2 answers
  • Please help me if possible<br>​
    6·1 answer
  • Why is knowing the density of water important to us? Give a reasonable answer
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!