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3 years ago

The number 199,078 has how many significant digits?

Chemistry

1 answer:

nikitadnepr [17]3 years ago

8 0

I think it's 6

Explanation:

zeros between other nonzero digits are significant

ex. 50.3 has 3 significant figures. ex. 8101.01 has 6 significant figures

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reddit The amount of NE released by sympathetic nerve terminals will be most strongly influenced by a change in which of the fol

erastovalidia [21]

Answer: Extracellular [Ca2+]

Explanation:

The sensitivity and density of the alpha receptors serve to enhance the response to the release of norepinephrine (NE) . However, they do not exert a strong influence as the concentration of calcium ions on the amount of norepinephrine (NE) released by sympathic nerve terminals.

The release of neurotransmitters depends more on either an external or internal stimulus.This results in an action potential which on reaching a nerve terminal, results in the opening of Ca²⁺ channels in the neuronal membrane. Because the extracellular concentration of Ca²⁺ is greater than the intracellular Ca²⁺ concentration, Ca²⁺ flows into the nerve terminal. This triggers a series of events that cause the vesicles containing norepinephrine (NE) to fuse with the plasma membrane and release norepinephrine (NE) into the synapse. The higher the action potential, the higher the Ca²⁺ flow into the terminals resulting in higher amount of norepinephrine (NE) into the synapse, and vice versa.

Catechol-O-methyltransferase (COMT) is one of several enzymes that degrade catecholamines such as dopamine, epinephrine, and norepinephrine. It serves a regulatory purpose to lower the concentration of norepinephrine upon its release from nerve terminals.

8 0

3 years ago

When an oxidant is present, vitamin C can be converted to a product described as (5R)-5-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxy-

Step2247 [10]

Answer:

D) Vitamin C is oxidized to yield a furan ring with 3 carbonyl groups and no double bonds

Explanation:

We can tell that the compound " (5R)-5-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxy-furan-2,3,4(5H)-trione " has 3 carbonyl groups due to it having "trione" in the name (and it lacking other carbonyl group names, like amide or carboxylic acid).

As there is no "-ene" part of the name referencing a double bond, the only option left is option D).

3 0

3 years ago

According to valence bond theory, the minimum of the potential energy curve describing the interaction of H atoms in H2 correspo

tatuchka [14]

The interaction between the two atoms of H in H2 with the lower energy corresponds to a covalent bond between hydrogen's.

When the two atoms of H form a bond, they are overlapping the individual orbitals to form a new one. Every hydrogen has 1 electron which sits in a 1s orbital and then form one molecular orbital. The energy of H2 is lower than individual hydrogens because the electrostatic interaction between them.

7 0

3 years ago

Calculate the energy released in each of the following fusion reactions. Give your answers in MeV. (a) 2H + 3H → 4He + n 17.54 C

Vikentia [17]

Answer:

a) E = 17.55 MeV

b) E = 18.99 MeV

c) E = 3.29 MeV

d) You can use the methods applied for the other parts to solve this, the equation is not properly written

e) E = 4.075 MeV

Explanation:

Energy Released, $E = \triangle M * 931.5$

$\triangle M = \sum M_{product} - \sum M_{reactant}$

Mass of 1H, $M_{H} = 1.007823$

Mass of 2H, $M_{2H} = 2.0141u$

Mass of 3H, $M_{3H} = 3.016 u$

Mass of Helium, $M_{4He} = 4.002602u$

Mass of Beryllium, $M_{7Be} = 7.01693 u$

Mass of neutron, $M_{n} = 1.008664 u$

a) $2H + 3H \rightarrow 4He + n$

$\triangle M = (4M_{He} + M_{n} ) - (2M_{H} + 3 M_{H} )\\\triangle M = ( 4.0026 + 1.008664) - (2.0141 + 3.016 )\\\triangle M = -0.01884u$

Energy released,

$E = -0.01884 * 931.5\\E = -17.55 Mev$

Energy released = 17.55 MeV

b) $4He + 4He \rightarrow 7Be + n$

$\triangle M = (M_{7Be} + M_{n} ) - (M_{4He} + M_{4He} )\\\triangle M = ( 7.01693 + 1.008664) - (4.002602 + 4.002602 )\\\triangle M = 0.02039 u$

Energy released,

$E = 0.02039 * 931.5\\E = 18.99 Mev$

c) $2H + 2H \rightarrow 3 He$ + n

$\triangle M = (M_{3He} + M_{n} ) - (M_{2H} + M_{2H} )\\\triangle M = ( 3.016 + 1.008664) - (2.0141 + 2.0141 )\\\triangle M = -0.003536 u$

Energy released,

$E = -0.003536 * 931.5\\E = -3.29 Mev$

E = 3.29 MeV(Energy is released)

d) You can use the methods applied for the other parts to solve this, the equation is not properly written

e) $2H + 2H \rightarrow 3H + 1H$

$\triangle M = (M_{3H} + M_{1H} ) - (M_{2H} + M_{2H} )\\\triangle M = ( 3.016 + 1.007825) - (2.0141 + 2.0141 )\\\triangle M = -0.00435 u$

$E = -0.00435 * 931.5\\E =-4.075 Mev$

E = 4.075 MeV ( Energy is released)

5 0

3 years ago

How are rewards and punishments different from positive and negative reinforcement?

kap26 [50]

So basically Positive reinforcement is when you give someone something for showing a good behavior, and a negative reinforcement is giving someone a consequence for showing bad behavior.

Hope this helps:)

8 0

3 years ago