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
Romashka [77]
2 years ago
11

Sodium-25 was to be used in an experiment, but it took 3.0 minutes to get the sodium from the reactor to the laboratory. If 8.0

mg of sodium-25 was removed from the reactor, how many mg of sodium-25 were placed in the reaction vessel 3.0 minutes later if the half life of sodium-25 is 60 seconds.
Chemistry
1 answer:
Ksenya-84 [330]2 years ago
5 0

Sodium-25 after 3 minutes : 1.0625 mg

<h3>Further explanation</h3>

General formulas used in decay:  

\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}

T = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

<h3 />

No=8 mg

t1/2=60 s

T=3 min=180 s

\tt Nt=No\dfrac{1}{2}^{T/t1/2}\\\\Nt=8.5\dfrac{1}{2}^{180/60}\\\\Nt=8.5(\dfrac{1}{2})^3\\\\Nt=1.0625~mg

You might be interested in
Help me make a hypothesis out of this question for my project.
Lubov Fominskaja [6]
Animals are able to see much more clearly in the dark than humans can.

Or

Humans are able to see much more clearly in the dark than animals can.
7 0
3 years ago
how many moles of iodine should be added to 750 grams of carbon tetrachloride to prepare a 0.24 m solution
aleksley [76]

Answer:

0.18 mol

Explanation:

Given data

  • Mass of carbon tetrachloride (solvent): 750 g
  • Molality of the solution: 0.24 m
  • Moles of iodine (solute): ?

Step 1: Convert the mass of the solvent to kilograms

We will use the relationship 1 kg = 1,000 g.

750g \times \frac{1kg}{1,000g} =0.750kg

Step 2: Calculate the moles of the solute

The molality is equal to the moles of solute divided by the kilograms of solvent. Then,

m = \frac{moles\ of\ solute }{kilograms\ of\ solvent} \\moles\ of\ solute = m \times kilograms\ of\ solvent = \frac{0.24mol}{kg}  \times 0.750kg = 0.18 mol

6 0
3 years ago
Read 2 more answers
What is the % by volume of 50mL of ethylene glycol dissolved in 950mL of H2O?
MariettaO [177]

Answer:

5.0 %

Explanation:

Given data

  • Volume of ethylene glycol (solute): 50 mL
  • Volume of water (solvent): 950 mL

Step 1: Calculate the volume of solution

If we assume that <em>the volumes are additive</em>, the volume of the solution is equal to the sum of the volume of the solute and the solvent.

V = 50 mL + 950 mL = 1000 mL

Step 2: Calculate the percent by volume

We will use the following expression.

\% v/v = \frac{volume\ of\ solute}{volume\ of\ solution} \times 100 \%  = \frac{50mL}{1000mL} \times 100 \% = 5.0\%

5 0
3 years ago
Increasing temperature can
SOVA2 [1]
A- Change the phase of the matter
7 0
3 years ago
Why do cells prefer to use carbohydrates as a source of energy before they use fats and proteins.
Semmy [17]

The primary role of carbohydrates is to supply energy to all cells in the body. Many cells prefer glucose as a source of energy versus other compounds like fatty acids. Because the energy from glucose comes from the chemical bonds between the carbon atoms.

7 0
2 years ago
Read 2 more answers
Other questions:
  • Which formed first: hydrogen nuclei or hydrogen atoms?
    15·1 answer
  • Difference between protons neutrons and electrons?
    11·2 answers
  • What components are needed in a expeirment
    14·1 answer
  • Which of these best describes Earth’s core?
    15·2 answers
  • How many atoms of oxygen are there in one molecule of carbon dioxide, if the chemical formula is CO2?
    8·2 answers
  • This is the chemical formula for carvone (the chemical that gives spearmint its flavor): An organic chemist has determined by me
    11·1 answer
  • Covalent bonds involve the sharing of?
    10·1 answer
  • Please help!
    11·1 answer
  • 1.0 gallon to mm<br>N.B 1 gallon=3.8L​
    5·1 answer
  • Which of the following are characteristics of a gas? (Select all that apply.)
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!