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
Assoli18 [71]
3 years ago
6

After 4 half-lives have elapsed, the amount of a radioactive sample which has not decayed is

Chemistry
1 answer:
ra1l [238]3 years ago
3 0

The answer gonna be: 1/2^n = 1/2^4 = 0.0625

So, 6.25% sample has not decayed yet!!!

You might be interested in
Adding heat and increasing concentration are meant to cause an increase in....?
asambeis [7]

Answer:

Adding heat and increasing concentration are meant to cause an increase in the rate of a reaction

Explanation:

The rate of a chemical reaction is defined as the number of moles of reactants converted or products formed pee unit time. It is a measure of how quickly the reactants in a given reaction are used up to form products or how quickly products are formed from reactants.

Factors that affect the rate of a chemical reaction include:

1. Nature of reactants

2. Concentration/pressure (for gases) of reactants

3. Temperature of reaction mixture

4. Presence of light

5. Presence of a catalyst

The effect of increasing the concentration of reactants for a given chemical reaction is that the reaction rate will increase. This is so because, according to the collision theory of chemical reactions, the frequency of collision between reactant particles which results in a chemical reaction (effective collisions) will increase when the reactant particles are crowded together in a small space due to an increase in their concentration.

The effect of increasing temperature or adding heat to a reaction is that the reaction rate increases. When the heat is added to a reactant particles, the number of particles with energies greater than or equal to the activation energy (the minimum amount of energy that reactant particles must possess for effective collisions) increases. Also, the average speed of the reactant particles increases resulting in a greater frequency of collision. Hence, the rate of the chemical reaction increases.

4 0
3 years ago
The combustion reaction for methane is shown below:
horrorfan [7]

Answer:

P =  14.1 atm    

Explanation:

Given data:

Mass of methane = 64 g

pressure exerted by water vapors = ?

Volume of engine = 24.0 L

Temperature = 515 K

Solution:

Chemical equation:

CH₄ + 2O₂      →      CO₂ + 2H₂O + energy

Number of moles of methane:

Number of moles = mass / molar mass

number of moles = 64 g/ 16 g/mol

Number of moles = 4 mol

Now we will compare the moles of water vapors and methane.

              CH₄          :            H₂O  

                 1            :             2

                 4            :         2/1×4 = 8 mol

Pressure of water vapors:

PV = nRT

R = general gas constant = 0.0821 atm.L/mol.K

P = 8 mol × 0.0821 atm.L/mol.K× 515 K / 24.0 L

P = 338.25 atm.L/ /  24.0 L

P =  14.1 atm      

4 0
3 years ago
Within an atom, electrons A. are in motion inside the nucleus. B. are in motion outside the nucleus. C. are inside the nucleus a
marin [14]

Hello! The correct answer is, B. are in motion outside the nucleus.


I hope this helped!

4 0
4 years ago
Read 2 more answers
N2 (g) + __ H2 (g) --> _NH3 When the reaction above is completely
Advocard [28]

Answer:

3

Explanation:

left side has 2 N so right side must have a 2 which means 6 H on right side so to get 6 on left you have a coef. of 3 to make 6 H

7 0
2 years ago
Using water to measure the volume of small irregular shaped objects is called? *
Fed [463]

Answer:

B. water displacement is used "graduated cylinder is filled with water (100 mL) and the object is then put inside. ... If the new water level is (120 mL) we now know that the object has a volume of 20 mL."

Explanation:

4 0
2 years ago
Read 2 more answers
Other questions:
  • Which of these items best describes the arrangement of electrons in an atom of sulfur? A. Two electrons in its first energy leve
    15·1 answer
  • Copper occurs in nature in the form of two isotopes, Cu-63 and Cu-65. Its correctly recorded atomic mass (weighted average) is 6
    11·1 answer
  • 8 Which elements have the most similar chemical properties?
    13·2 answers
  • Whitch constellation has the most stars
    14·1 answer
  • Write and balance the equation for the complete combustion of acetylene, C2H2. You do not need to include any phase symbols or e
    7·2 answers
  • Which molecular formula is also an empirical formula? <br> 1)C6h6<br> 2)h2o2<br> 3) n2h4<br> 4) n2o5
    13·2 answers
  • Complete the chart
    15·1 answer
  • The four structures that both prokaryotic and eukaryotic cells have are
    5·1 answer
  • C3H8 (g)+ 502 (g)  3CO2 (g) + 4 H2O (g) + 531 kcal
    7·1 answer
  • A 50.0- mL volume of 0.15 M HBr is titrated with 0.25 M KOH . Calculate the pH after the addition of 14.0 mL of KOH
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!