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
STatiana [176]
3 years ago
7

Uranium-238 decays very slowly.its half-life is 4.47 billion years.

Chemistry
2 answers:
aleksandrvk [35]3 years ago
7 0

Answer:

12.53 % of a sample of Uranium-238 will remain after 13.4 billion years.

Explanation:

The half life of the uranium-238 = t_{\frac{1}{2}}=4.47 billion years

All the radioactive reaction are of first order kinetics. The rate constant and t half of the reaction are related as:

k=\frac{0.693}{t_{\frac{1}{2}}}=\frac{0.693}{4.47 \text{billion years}}=0.1550 (\text{billion years})^{-1}

k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}

where,  

k = rate constant = 0.1550 (\text{billion years})^{-1}

t = time taken during radio decay  = 4.47 billion years

[A_o] = initial amount of the reactant = 1.45\times 10^{-6}mol/L

[A] = amount left left after time t.

\log \frac{[A]}{[A_o]}=-\frac{kt}{2.303}

\frac{[A]}{[A_o]}=0.1253=\frac{12.53}{100}=12.53\%

12.53 % of a sample of Uranium-238 will remain after 13.4 billion years.

coldgirl [10]3 years ago
6 0
13.4 billion years is 3 times of the half-life, 4.47 billion years. So the Uranium-238 will go through three times of half decay. So the remain percentage will be 50%*50%*50%=12.5%.
You might be interested in
How many moles of HCl are found in 500mL of HCl solution with pH of 3​
Alexxx [7]

Answer:

Number of moles = 0.0005 mol.

Explanation:

Given data:

pH = 3

Volume of solution = 500 mL

Number of moles = ?

Solution:

HCl dissociate to gives H⁺ and Cl⁻

HCl → H⁺ + Cl⁻

It is known that,

pH = -log [H⁺]

3 = -log [H⁺]

[H⁺] = 10⁻³ M

[H⁺] = 0.001 M

Number of moles of HCl:

Molarity = number of moles / Volume in litter

Number of moles = Molarity × Volume in litter

Number of moles = 0.001 mol/L × 0.5 L

Number of moles = 0.0005 mol

7 0
3 years ago
The name of an alcohol side chain is known as an alkoxy group. True or false?
mylen [45]
By itself, i don’t think so.

though, paired with a hydrogen bond, it is.

If i’m wrong, please feel free to let me know :)
6 0
3 years ago
Help me I got stuck<br> Pls
Sophie [7]
The answer is C because the weight is going down so they form a gas.
3 0
3 years ago
You'll be given 100 points if you answer this question!!!!!!!!!!!!
storchak [24]

Answer:conducts ,steel, polystyrene, thermal insulation

Explanation:

5 0
3 years ago
You are given solutions of hcl and naoh and must determine their concentrations. you use 27.5 ml of naoh to titrate 100.0 ml of
Dafna1 [17]
1) Start by standardizing the solution of NaOH by using the solution of H2SO4 whose concentration is known.

2) Equation:

2Na OH + H2SO4 --> Na2 SO4 + 2H2O

3) molar ratios

2 mol NaOH : 1 mol H2SO4

4) Number of moles of H2SO4 in 50.0 ml of 0.0782 M solution

M = n / V => n = M*V = 0.0782 M * 0.050 l = 0.00391 mol H2SO4

5) Number of moles of NaOH

2 moles NaOH / 1mol H2SO4 * 0.00391 mol H2SO4 = 0.00782 mol NaOH

6) Concentration of the solution of NaOH

M = n / V = 0.00782 mol / 0.0184 ml = 0.425 M

7) Standardize the solution of HCl

Chemical reaction:

NaOH + HCl --> NaCl + H2O

8) Molar ratios

1 mol NaOH : 1 mol HCl

9) Number of moles of NaOH in 27.5 ml

M = n / V => n = M * V = 0.425 M * 0.0275 l = 0.01169 moles NaOH

10) Number of moles of HCl

1 mol HCl / 1mol NaOH * 0.01169 mol NaOH = 0.01169 mol HCl

11) Concentration of the solution of HCl

M = n / V = 0.01169 mol / 0.100 l = 0.1169 M

Rounded to 3 significant figures = 0.117 M

Answers:

[NaOH] = 0.425 M
[HCl] = 0.117 M
3 0
3 years ago
Other questions:
  • Choose the covalent compounds from the following choices Br2 MgS SO2 KF
    7·1 answer
  • Attempt 3 An irregular lump of an unknown metal has a measured density of 5.50 g/mL. The metal is heated to a temperature of 153
    8·1 answer
  • Choose the abiotic factors that characterize the tundra biome.
    6·2 answers
  • A primary purpose of conducting a hazardous materials exercise is to find out:
    9·1 answer
  • Which of the following choices is an example of a nonvascular plant?
    9·1 answer
  • What starting compound and what reagents should be used for most efficient synthesis of 2-bromo-1-iso-propyl-4-nitrobenzene? Eff
    13·1 answer
  • Which compound that directly provides energy in living cells is being produced in every tube where cellular respiration is occur
    5·1 answer
  • How is stoichiometry used to calculate amount of product from amount of reactant?
    15·1 answer
  • Calculate the mass, in grams, of 0.965 mol of sodium hydroxide
    12·1 answer
  • Consider the reaction below. 2al2o3 → 4al 3o2 what is the mole ratio of oxygen to aluminum? o2:al = :4
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!