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
timofeeve [1]
3 years ago
7

what is the half life isotope if after 21 days you have 31.25 g remaining from a 250.0 g starting sample size?

Chemistry
1 answer:
alexgriva [62]3 years ago
3 0

250 --> 125 --> 62.5 --> 31.25


each arrow equals one half life, so 3 half lives


14 days/ 3 half lives =


4.67 days = half life

You might be interested in
Which statements accurately describe soap? Select one or more:
tia_tia [17]

Answer:

A. Soaps react with ions in hard water to create a precipitate.

B. Soaps are both hydrophobic and hydrophilic.

D. Soaps should be weakly alkaline in solution.

Explanation:

A. Hard water contains <u>magnesium and calcium minerals</u> like calcium and magnesium carbonates, sulfates and bicarbonates. As soon as these minerals come in contact with soap their ions like Mg²⁺ & Ca²⁺ form precipitates.

B. Soap are both hydrophilic and hydrophobic. They reason why they exhibit both the properties is really important for their functionality. The hydrophobic part of soap makes interaction with oil/dust particles while the hydrophilic part makes interaction with water. When the cloth is rinsed the dirt/soap particles are removed from the dirty clothes thereby making them clean.

C. Soaps have alkaline pH i.e. more than 7 that is why they have bitter taste.

5 0
3 years ago
Calculate the osmotic pressure of a solution containing 24.6g of glycerin in 250ml of solution at 298K
gavmur [86]
The formula to calculate osmotic pressure is 
Osmotic Pressure = M R T
M = Molarity
R = Ideal Gas Constant
T = Temperature in Kelvin

So, 
24.6/.2254kg=109.139g /kg  >>>>> Molarity
109.139 x mols/92 g = 1.186 mols kg^-1
1.186 x 0.08134 x 298 K = 28.755 atm
<span>1.06852 x 0.08134 x 298K= 26.5 atm

The answer is 26.5</span>
6 0
3 years ago
if the climate warmed which of the following would be caused by rising temperatures? .a. an increase in sea levels. b. an increa
Klio2033 [76]

A warming climate can cause seawater to expand and ice over land to melt, both of which can cause a rise in sea level. Storm surge on a Louisiana highway shows the effects of rising sea levels. Many people are interested in climate change and how a changing climate will affect the ocean.

5 0
3 years ago
Sulfur dioxide and oxygen react to form sulfur trioxide during one of the key steps in sulfuric acid synthesis. An industrial ch
guajiro [1.7K]

Answer:

Kp = 0.049

Explanation:

The equilibrium in question is;

2 SO₂ (g)  +  O₂ (g)   ⇄ 2 SO₃ (g)  

Kp = p SO₃² / ( p SO₂² x p O₂ )

The initial pressures are given, so lets set up the ICE table for the equilibrium:

atm        SO₂         O₂          SO₃

I              3.3        0.79           0

C              -2x           -x          2x

E             3.3 - 2x    0.79 - x    2x

We are told 2x = partial pressure of SO₃ is 0.47 atm at equilibrium, so we can determine the partial pressures of  SO₂ and O₂ as follows:

p SO₂  = 3.3 -0.47 atm = 2.83 atm

p O₂ = 0.79 - (0.47/2) atm = .56 atm

Now we can calculate Kp:

Kp = 0.47² /[ ( 2.83 )² x 0.56 ] = 0.049 ( rounded to 2 significant figures )

Note that we have extra data in this problem we did not need since once we setup the ICE table for the equilibrium we realize we have all the information needed to solve the question.

7 0
3 years ago
Does anyone know how to do this???
Bond [772]
Simply look at the periodic table and fill in what you know based on the table

The number of protons = atomic number
The number of electrons, Which is the same as the atomic number for atoms.

The number of valence electrons that is given by the group that the element is in, the top number of each column in the periodic table.







8 0
3 years ago
Other questions:
  • Which of these is a compound?<br> A)air<br> Boxygen<br> C)carbon dioxide<br> D)carbon
    13·2 answers
  • A 20.0 milliliter sample of 0.200 molar K₂CO₃ solution is added to 30.0 milliliters of 0.400 molar Ba(NO₃)₂ solution. Barium car
    12·1 answer
  • Who made the idea that as you go down the periodic table the atomic radius increases and the first ionization energy decreases?
    14·2 answers
  • To what volume should 5.06 mL of an 7.83 M sulfuric acid solution be diluted in order to obtain a final solution that is 2.36 M?
    10·1 answer
  • If a resource is nonrenewable, it
    9·1 answer
  • Which of the following is a synthesis reaction? 2Na + 2H 2O 2NaOH + H 2 2S + 3O 2 2SO 3 2H 2O 2 2H 2O + O 2 CaCl 2 + F 2 CaF 2 +
    9·1 answer
  • If lamp 1 is unscrewed from its holder, what will happen to lamp 2 and why?
    11·1 answer
  • Helppppp pleaseeee xxxxxx
    10·1 answer
  • Explain why ionic compounds are formed when a metal bonds with a nonmetal, but covalent compounds are formed when two nonmetals
    12·2 answers
  • Given the balanced equation representing a reaction:
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!