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3 years ago

Iodine-131 is used to

1 answer:

7 0

Iodine 131 is a radioisotope with a very short half-life of 8.02 days, making it highly radioactive. Frequently used in small doses in thyroid cancers therapies, it is also one of the most feared fission products when accidentally released into the environment. Radiotoxicity of iodine 131.

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Answer each of the following questions with increases, decreases, or does not change.

Nitella [24]

Answer:

a) increases

b) decreases

c) does not change

d) increases

Explanation:

The vapour pressure of a liquid is dependent on;

I) the magnitude of intermolecular forces

II) the temperature of the liquid

Hence, when any of these increases, the vapour pressure increases likewise.

Similarly, the boiling point of a liquid depends on the magnitude of intermolecular forces present because as intermolecular forces increases, more energy is required to break intermolecular bonds.

Lastly, increase in surface area of a liquid does not really affect it's vapour pressure.

7 0

3 years ago

wich answer choice contains organisms that are all prokaryotic. A. archaebacteria and bacteria B. bacteria and fungi C. protists

JulijaS [17]

Answer:

Explanation:

6 0

3 years ago

A certain liquid X has a normal boiling point of 108.30 °C and a boiling point elevation constant Kb=1.07 °C kg/mol. A solution

Fynjy0 [20]

Answer:

34,6g of (NH₄)₂SO₄

Explanation:

The boiling-point elevation describes the phenomenon in which the boiling point of a liquid increases with the addition of a compound. The formula is:

ΔT = kb×m

Where ΔT is Tsolution - T solvent; kb is ebullioscopic constant and m is molality of ions in solution.

For the problem:

ΔT = 109,7°C-108,3°C = 1,4°C

kb = 1.07 °C kg/mol

Solving:

m = 1,31 mol/kg

As mass of X = 600g = 0,600kg:

1,31mol/kg×0,600kg = 0,785 moles of ions. As (NH₄)₂SO₄ has three ions:

0,785 moles of ions× $\frac{1(NH_{4})_{2}SO_{4}}{3Ions}$ = 0,262 moles of (NH₄)₂SO₄

As molar mass of (NH₄)₂SO₄ is 132,14g/mol:

0,262 moles of (NH₄)₂SO₄× $\frac{132,14g}{1mol}$ = <em>34,6g of (NH₄)₂SO₄</em>

I hope it helps!

7 0

3 years ago

Alchemists were medieval scholars and philosophers who were the forerunners of modern-day chemists. many tried repeatedly to tra

AlladinOne [14]

Answer is: because they were using simple chemical reactions to transform elements, but that is possible only with nuclear reactions, which in that time were not possible to conduct.

Nuclear reactions can produce new elements, because number of protons and neutrons is changed, lead and gold have different atomic and mass numbers.

The electrons of an atom participates in a chemical reaction, chemical reactions involve the rearrangement of electrons, because there is transfer, loss, gain and sharing of electrons in chemical reactions, new elements are not formed.

8 0

3 years ago

In your discussion consider a SN2 reaction mechanism concept. Propose a modification of experimental procedure that would improv

Hitman42 [59]

Answer:

Here's what I get

Explanation:

You may have done a Williamson synthesis of guaifenesin by reacting guaiacol with 3-chloropropane-1,2-diol.

A. Mechanism

Step 1

NaOH converts guaiacol into a phenoxide ion.

Step 2

The phenoxide acts as the nucleophile in an SN2 reaction to displace the Cl from the alkyl halide.

B. Improve the yield

You probably carried out the reaction in ethanol solution — a polar protic solvent.

You might try doing the reaction in a polar aprotic solvent— perhaps DMSO.

A polar aprotic solvent does not hydrogen bond to nucleophiles, so they become stronger.

C. Another method of ether synthesis —dehydration of alcohols

Sulfuric acid catalyzes the conversion of primary alcohols to ethers.

This is also a nucleophilic displacement reaction.

Protonation of the OH converts it into a better leaving group.

Attack by a second molecule of alcohol forms the protonated ether.

A molecule of water then removes the proton.

6 0

3 years ago