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Ghella [55]
3 years ago
15

(25 points) A certain isotope of technetium has a half-life of 8 hours. How much of a 40 gram sample will be left after 16 hours

?
A. 10 grams
B. 40 grams
C. 5 grams
D. 20 grams
Chemistry
1 answer:
gtnhenbr [62]3 years ago
6 0

Answer:

A) 10 grams

Explanation:

16 hours = 2 half lives

This means that the number is divided in half twice.

40/2 = 20

20/2 = 10

I hope this helps!! :)

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What happens to the particles during solid to a liquid
Ratling [72]

the particles from solid to liquid start to move around faster then it was at the first state

3 0
3 years ago
Why amino acids are soluble in pH=3 or pH=10 solutions more than it dissolves in pH=7 solutions?
Ray Of Light [21]

Answer:

Solubility is Affected by pH

The pH of an aqueous solution can affect the solubility of the solute. By changing the pH of the solution, you can change the charge state of the solute.

At pH extremes, the amino acid molecules mostly carry a net charge, thus increasing their solubility in polar solvent. At very low or very high pH, the amino acid molecules have increased charge, thus form more salt bonds with water solvent molecules.

An isoelectric point is the pH at which an amino acid exists as its zwitterion. A zwitterion is the dipolar ionic form of an amino acid. ... If the pH is lower (in acidic conditions) than the isoelectric point then the amino acid acts as a base and accepts a proton at the amino group. This gives it a positive change.

An amino acid is usually more soluble in aqueous solvent at pH extremes than it is at a pH near the isolelectric point of the amino acid. (Note that this does not mean that the amino acid is insoluble at a pH near its pI.)

Which of the following statements correctly explains this phenomenon?

(Select all that apply.)

The neutral charge of an amino acid molecule at its isoelectric point will make the molecule hydrophobic.

At pH extremes, the amino acid molecules mostly carry a net charge, thus increasing their solubility in polar solvent.

At very low or very high pH, the amino acid molecules have increased charge, thus form more salt bonds with water solvent molecules.

At pH values far from the isoelectric point, individual amino acid molecules have greater kinetic energy, thus more readily stay in solution.

<h2>Please mark me as brainliest</h2>

8 0
3 years ago
The ingredients of the soda are best described as : Mixtures, compounds, or elements.
stira [4]

Answer:

Compound

Explanation:

Soda itself is a mixture made out of compounds.

5 0
4 years ago
Compound X has the formula C8H14. X reacts with one molar equivalent of hydrogen in the presence of a palladium catalyst to form
REY [17]

Answer:

1-Ethyl-3-methylidenecyclopentane  

Step-by-step explanation:

Formula = C₈H₁₄. An alkane has formula C₈H₁₈. ∴ X contains 2 double bonds, 2 rings, or 1 ring and 1 double bond.

X absorbs only 1 mol of hydrogen. ∴ X contains 1 ring and 1 double bond.

Hydrogenation gives 1-ethyl-3-methylcyclopentane.

Ozonolysis gives formaldehyde, so X must contain a =CH₂ group.  

Hydrogenation of X converted the =CH₂ to -CH₃.

X is 1-ethyl-3-methylidenecyclopentane.

You can see the reactions in the image below.

3 0
3 years ago
A 90.0 g sample of NaOH is dissolved in water and the solution is diluted to give a final volume of 3.00 liters. The molarity of
Y_Kistochka [10]
First convert grams to moles:
90.0g *(mole/39.997) = 2.250mole
Remember that molarity is moles per liters:
2.250mol/3L = .750 M
8 0
3 years ago
Read 2 more answers
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