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
strojnjashka [21]
3 years ago
11

Help please!!

Chemistry
1 answer:
frez [133]3 years ago
7 0

Answer:

6.25%

Explanation:

Given data:

Half life of lutetium-117 = 6.75 days

Percentage remaining after 27 days = ?

Solution;

Number of half lives = Time elapsed / half life

Number of half lives = 27 days / 6.75 days

Number of half lives = 4

At time zero = 100%

At first half life = 100%/2 = 50%

At second half life = 50%/2 = 25%

At 3rd half life = 25%/2 = 12.5%

At 4th half life = 12.5%/2 = 6.25%

You might be interested in
Explain how to calculate net force.
Alisiya [41]
Force acting on the body when the body is at rest the net formals is given
6 0
3 years ago
When sodium is excited in a flame, two ultraviolet spectral lines at (wave length symbol)=372.1 nm and (wave length symbol)=376.
uranmaximum [27]
<span>Higher energy = shorter wavelength
Frequency is one cycle over an amount of time (seconds)
So higher frequency = higher energy = shorter wavelength</span>
5 0
4 years ago
Read 2 more answers
A device that does work in a circuit is called what ?
zavuch27 [327]
These are called resistors. 
7 0
3 years ago
Read 2 more answers
How is the mass of 1 mole of an element determined
Tatiana [17]

One mole (abbreviated mol) is equal to 6.022×1023 molecular entities (Avogadro's number), and each element has a different molar mass depending on the weight of 6.022×1023 of its atoms (1 mole). The molar mass of any element can be determined by finding the atomic mass of the element on the periodic table.
3 0
3 years ago
What is the number of moles in 526 L O2 at STP?
Katena32 [7]
526 L O2 x 1 mol O2 / 22.4 L = 23.5 mol O2
3 0
3 years ago
Read 2 more answers
Other questions:
  • Which of the following is a change in which the identity of the substance
    12·1 answer
  • Which one of these is a mixture ?
    15·1 answer
  • When Mendeleev organized the elements by their _________, he noticed the properties of elements repeated.
    13·1 answer
  • How much energy is needed to raise the temperature of a 200 g piece of lead by 250 o C?
    11·1 answer
  • One compound in the list below is a gas at room conditions, while all of the others are liquids or solids. For each compound, in
    13·1 answer
  • What is the number of moles of solute in 250 mL of a 0.4 M solution?
    7·1 answer
  • A quantity of water is heated from 25.0°C to 36.4°C by absorbing 325 J of heat energy. If the specific heat of water is 4.18 J /
    10·1 answer
  • Rotting food is an example of a chemical reaction. Many foods will not quickly less kept in a refrigerator. From this
    9·1 answer
  • Mixture are combination of two or more substances that can be​
    7·1 answer
  • Why is copper used to make hot water tanks not steel.
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!