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zubka84 [21]
3 years ago
11

What is the product of a positron and electron combining then undergoing annihilation during the pet imaging process? a. two 511

kev photons are formed. b. x-rays are formed. c. a single gamma ray is formed. d. two high-speed beta particles are formed?
Chemistry
1 answer:
jekas [21]3 years ago
5 0
Answer is: <span>a. two 511 kEv photons are formed.
</span><span>When the positrons reach thermal energies, they start to interact with electrons by annihilation.</span>
Positron-emission tomography<span> (</span>PET)<span> is a </span>nuclear medicine functional imaging<span> technique that is used to observe metabolic processes in the body. The system detects pairs of </span>gamma rays<span> emitted indirectly by a </span>positron<span>-emitting </span>radionuclide.
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MaRussiya [10]

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3 0
4 years ago
When 16.0 g of an unknown compound (a nonelectrolyte) are dis solved in exactly 800. g of water, the solution has a freezing poi
dexar [7]

Answer:

A. 266g/mol

Explanation:

A colligative property of matter is freezing point depression. The formula is:

ΔT = i×Kf×m <em>(1)</em>

Where:

ΔT is change in temperature (0°C - -0,14°C = 0,14°C)i is Van't Hoff factor (1 for a nonelectrolyte dissolved in water), kf is freezing point molar constant of solvent (1,86°Cm⁻¹) and m is molality of the solution (moles of solute per kg of solution). The mass of the solution is 816,0g

Replacing in (1):

0,14°C = 1×1,86°Cm⁻¹× mol Solute / 0,816kg

<em>0,0614 = mol of solute</em>.

As molar mass is defined as grams per mole of substance and the compound weights 16,0g:

16,0g / 0,0614 mol = 261 g/mol ≈ <em>A. 266g/mol</em>

I hope it helps!

3 0
3 years ago
Given the following Fischer projection: Fischer projection for an entantiomer of 2-bromo-2,3-dihydroxypropanal with the bromine
harina [27]

Answer:

Explanation:

Stereoisomers are two or more atoms that  have the same bonding order of atoms but there is a difference  spatial arrangement of  the  atoms in space.

A plane of symmetry divides a molecule into two equal halves.

A chiral stereoisomer are not superimposed on a mirror image , Hence they do not posses a plane of symmetry.

As a result to that. these non-superimposable mirror images are said to be Enantiomers.

However, a Fischer Projection emanates from a two - dimensional figure which is used for presenting a three - dimensional organic molecules.

From the given question;

Fischer projection for an enantiomer of 2-bromo-2,3-dihydroxypropanal with the bromine oriented horizontally to the left and the hydroxide group oriented horizontally to the right.

we can sketch the way the enantiomer of 2-bromo-2,3-dihydroxypropanal can  be seen like the one shown below:

              CH₂OH

                   |

                   |

                   |

Br -------------|----------------OH

                   |

                   |

                   |

                 CHO

The objective of this question is to drawn the perspective formula of the molecule.

So , from the attached file below; we can see the perspective formula of the molecule in a well structured 3-D format.

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3 years ago
How does the appear from earth
san4es73 [151]

Answer:

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8 0
3 years ago
1. You have three molecules of glucose (3C6H12O6). How many carbon atoms do you have?. . A. 3. . B. 6. . C. 18. . D. 36. 2. Whic
Leviafan [203]
One molecule of glucose has 6 carbon atoms. So if you have three molecules of glucose, simply multiply 3 by 6 carbon atoms. The correct answer is C. 18 Carbon atoms. 

The correct answer for the second questions is C. Air. A homogenous mixture is a mixture in which its components are uniformly distributed throughout the mixture. It has a sigle phase.
3 0
3 years ago
Read 2 more answers
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