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
pentagon [3]
3 years ago
13

The radioactive isotope of lead, Pb-209, decays at a rate proportional to the amount present at time t and has a half-life of 3.

3 hours. If 1 gram of this isotope is present initially, how long will it take for 75% of the lead to decay? (Round your answer to two decimal places.)
Chemistry
1 answer:
astraxan [27]3 years ago
5 0

Answer:

It will take 6.6 hours for 75% of the lead to decay.

Explanation:

The radioactive decay follows first order rate law

The half life and rate constant are related as

k=rate constant=\frac{0.693}{halflife}=\frac{0.693}{3.3}=0.21h^{-1}

The rate law for first order reaction is

time=\frac{1}{k}(ln[\frac{A_{0}}{A_{t}}]

Where

A0 = initial concentration = 1 g

At= final concentration = 0.25 g (as 75% undergoes decay so 25% left]

time=\frac{1}{0.21}(ln(\frac{1}{0.25})=6.6hours

You might be interested in
Before of an results an experiment are accepted, which of these points must it fulfill?
jek_recluse [69]

Answer:

I think it will be (B) only because you have to do it repeatedly and analyze it and not noted, in order for the results are accepted. I May be wrong. Thanks for letting me help you.

8 0
3 years ago
Which of the following correctly describes voltage difference?
7nadin3 [17]
Voltage difference is the push that causes charges to flow from high to low areas.
7 0
3 years ago
Determine if the following compounds are likely to have ionic or covalent bonds. a. Magnesium oxide (MgO) _______________ b. Str
nika2105 [10]

Answer:

The answer to your question is below

Explanation:

Ionic bond is a kind of bond in which a metal attaches to a nonmetal. Also we know that a molecule has ionic bonding if the electronegativity is higher than 1.7.

                    Kind of elements         Difference of electronegativity     Bond

a) MgO         Metal - Nonmetal                3.44 -  1.31 = 2.13                     Ionic

b) SrCl₂        Metal -Nonmetal                  3.16 - 0.95 = 2.21                    Ionic

c) O₃             Nonmetal- Nonmetal          3.44 - 3.44 = 0                      Covalent

d) CH₄O       Nonmetal-Nonmetal           3.44 - 2.55 = 0.89                Covalent

   Carbon, Hydrogen and oxygen are nonmetals

2) Silver coins can conduct electricity.

4 0
3 years ago
Can someone help me with this please....<br>​
Anna007 [38]

a. vinegar

b. Mineral deficiencies in the body can make joint pain worse. Because Vinegar contains the calcium, magnesium, potassium, and phosphorus your body needs, it helps as a supplement and therefore reduces pain.

1. in making fertilisers which are chemical compounds or salts to increase fertility of soil.

2. lithium hydroxide is used in space because of its high absorption of carbon dioxide and the small amount of heat produce by the reaction.

3. Acid rain has a lower pH than "normal" rain . Rain is naturally somewhat acidic with a pH between 5.0-5.5 typically. Acid rain has a pH that is below this: 4.4-4.2

4. lemon juice is an anti bacterial and a good germicidal solution which helps in removing the unseen bacteria on our hands.

<h3>Hope this helps :)</h3>
6 0
3 years ago
What is the mass of 8.0 x 10^26 UF6 molecules?
gulaghasi [49]
First, find the number of moles of UF6
Avagadro's number = 6.023 x 10^23

Number of moles = 8.0 x 10^26 / Avagadro's number = 8.0 x 10^26 / 6.023 x 10^23 = 1.328 x 10³ moles

Molecular weight of UF6 = Molecular weight of U (238.02891) + Molecular weight of F6 (6 x 18.9984032) = 238.02891 + 113.9904192 = 352.0193292 g/mol

Therefore mass of 8.0 x 10^26 UF6 molecules = 352.0193292 g/mol x 1.328 x 10³ moles = 467.481669 x 10³ grams




3 0
3 years ago
Other questions:
  • Write the formulas of the compounds formed by Al3+ with the following anions: NO3−, HCO3−, SO32−, PO43−. Use the given order of
    15·2 answers
  • What’s red lion fish habitat ?
    9·2 answers
  • An atom can be compared to our solar system because: The nucleus gives off light like the sun. Both electrons and planets move q
    10·2 answers
  • Can you help me on all of these question? (mostly on question number 4)
    11·2 answers
  • what concentration in parts per million in a solution that contains .008 grams of o2 dissolved in 1000 grams of water
    14·1 answer
  • Order the following elements from least to greatest ionization energy.
    5·1 answer
  • I need help with the table
    13·1 answer
  • Earth's atmosphere blocks short wavelengths of the electromagnetic spectrum. Which telescopes must be places in orbit around Ear
    5·1 answer
  • Someone talk to meeeeee ;( ​
    13·2 answers
  • Why is mining for coal a long-term concern?
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!