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
OleMash [197]
3 years ago
5

Radium-221 has a half-life of 30 sec. How long will it take for 96% of a sample to decay?

Chemistry
1 answer:
monitta3 years ago
3 0
We can calculate how long the decay by using the half-life equation. It is expressed as:

A = Ao e^-kt

<span>where A is the amount left at t years, Ao is the initial concentration, and k is a constant.
</span><span>From the half-life data, we can calculate for k.
</span>
1/2(Ao) = Ao e^-k(30)
<span>k = 0.023
</span>
0.04Ao = Ao e^0.023(t)
<span>t = 140 sec</span>
You might be interested in
A. Identify the structure drawn below.
nadya68 [22]

Answer:

Hexane

Explanation:

You have a carbon structure with only single bonds.  This means that the name will end in -ane.

There are 6 carbon atoms.  This means that the name will begin with hex-.

The structure is hexane.

7 0
3 years ago
The elements from this section of the periodic table all belong to the same
krok68 [10]

Answer:

Option C = same period.

Explanation:

All these elements belongs to second period of periodic table. This period consist of eight elements lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine and neon.

Electronic configuration of lithium:

Li₃ = [He] 2s¹

Electronic configuration of beryllium:

Be₄ = [He] 2s²

Electronic configuration of boron:

B₅ = [He] 2s² 2p¹

Electronic configuration of carbon:

C₆ = [He] 2s² 2p²

Electronic configuration of nitrogen:

N₇ = [He] 2s² 2p³

Electronic configuration of oxygen:

O₈ = [He] 2s² 2p⁴

Electronic configuration of fluorine:

F₉ = [He] 2s² 2p⁵

Electronic configuration of neon:

Ne₁₀ = [He] 2s² 2p⁶

All these elements present in same period having same electronic shell.

However their families, valance electrons and group are different. Boron have three valance electrons and belongs to group 3A. Carbon belongs to group 4A and have 4 valance electrons. Nitrogen belongs to group 5A and have five valance electrons. Oxygen belongs to group 6A and have six valance electrons. Fluorine belongs to group 7A and have seven valance electrons.

7 0
2 years ago
Read 2 more answers
A 10.0 gram sample of Fe contains how many miles of Fe
Dafna1 [17]

Answer:

1.7857 moles

Explanation:

moles=mass/Mr

10/56=1.7857

moles of iron =1.7857

4 0
2 years ago
Which term names the transfer of heat between two objects that are touching​
Svetlanka [38]

Answer: Conduction

Explanation:

Conduction means the process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material.

Meaning that its when an object touches another object and heat gets transferred.

5 0
3 years ago
3. What is the mass of HI used to create 2.50L of a 0.48 M solution of hydroiodic acid?
Daniel [21]

Answer:

Mass = 153.48 g

Explanation:

Given data:

Volume of solution = 2.50 L

Molarity = 0.48 M

Mass required = ?

Solution:

Molarity = number of moles / volume in litter

Number of moles = Molarity × volume in litter

Number of moles = 0.48 M  × 2.50 L

Number of moles =  1.2 mol

Mass of HI:

Number of moles = mass/molar mass

Mass = Number of moles × molar mass

Mass = 1.2 mol × 127.9 g/mol

Mass = 153.48 g

5 0
3 years ago
Other questions:
  • When a liquid loses heat it turns into a​
    8·2 answers
  • Describe the differences between bonding in an ionic compound and bonding in a covalent molecule.
    5·1 answer
  • How might a hurricane in Florida cause anomalous nest data
    15·1 answer
  • The number of unique open-chain structures corresponding to the molecular formula c3h5cl is:
    12·1 answer
  • Who was the first hispanic justice of the United States Supreme Court
    14·2 answers
  • Naphthalene combustion may be used to calibrate the heat capacity of a bomb calorimeter. The heat of combustion of naphthalene i
    7·1 answer
  • How many significant digits are there in the measurement 50,600 mg A)4 B)5 C)6 D)7
    10·2 answers
  • What is this equation balanced?
    5·1 answer
  • The mass of 0.10 mole of methane
    6·1 answer
  • Write the name for: Mg3O2
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!