Balance using the redox method:

Which moon phase does a solar eclipse occur in?

VARVARA [1.3K]

Answer:

full moon, i think

Explanation:

6 0

3 years ago

Read 2 more answers

Cytoplasm is a mixture of what two things?

alexira [117]

In cell biology, the cytoplasm is the material or protoplasm within a living cell, excluding the cell nucleus. It comprises cytosol (the gel-like substance enclosed within the cell membrane) and the organelles – the cell's internal sub-structures. All of the contents of the cells of prokaryote organisms (such as bacteria, which lack a cell nucleus) are contained within the cytoplasm. Within the cells of eukaryote organisms the contents of the cell nucleus are separated from the cytoplasm, and are then called thenucleoplasm. The cytoplasm is about 80% water and usually colorless.[1]

It is within the cytoplasm that most cellular activities occur, such as many metabolic pathways including glycolysis, and processes such as cell division. The concentrated inner area is called the endoplasm and the outer layer is called the cell cortex or theectoplasm.

Movement of calcium ions in and out of the cytoplasm is a signaling activity for metabolic processes.[2]

In plants, movement of the cytoplasm around vacuoles is known as cytoplasmic streaming.

6 0

3 years ago

How many moles of sodium carbonate are contained by 57.3g of sodium carbonate

Lady_Fox [76]

Answer:

$\boxed {\boxed {\sf 0.541 \ mol \ Na_2CO_3}}$

Explanation:

We are asked to find how many moles of sodium carbonate are in 57.3 grams of the substance.

Carbonate is CO₃ and has an oxidation number of -2. Sodium is Na and has an oxidation number of +1. There must be 2 moles of sodium so the charge of the sodium balances the charge of the carbonate. The formula is Na₂CO₃.

We will convert grams to moles using the molar mass or the mass of 1 mole of a substance. They are found on the Periodic Table as the atomic masses, but the units are grams per mole instead of atomic mass units. Look up the molar masses of the individual elements.

Na: 22.9897693 g/mol
C: 12.011 g/mol
O: 15.999 g/mol

Remember the formula contains subscripts. There are multiple moles of some elements in 1 mole of the compound. We multiply the element's molar mass by the subscript after it, then add everything together.

Na₂ = 22.9897693 * 2= 45.9795386 g/mol
O₃ = 15.999 * 3= 47.997 g/mol
Na₂CO₃= 45.9795386 + 12.011 + 47.997 =105.9875386 g/mol

We will convert using dimensional analysis. Set up a ratio using the molar mass.

$\frac {105.9875386 \ g \ Na_2CO_3}{1 \ mol \ Na_2CO_3}$

We are converting 57.3 grams to moles, so we multiply by this value.

$57.3 \ g \ Na_2CO_3} *\frac {105.9875386 \ g \ Na_2CO_3}{1 \ mol \ Na_2CO_3}$

Flip the ratio so the units of grams of sodium carbonate cancel.

$57.3 \ g \ Na_2CO_3} *\frac {1 \ mol \ Na_2CO_3}{105.9875386 \ g \ Na_2CO_3}$

$57.3 } *\frac {1 \ mol \ Na_2CO_3}{105.9875386 }$

$\frac {57.3 }{105.9875386 } \ mol \ Na_2CO_3$

$0.5406295944 \ mol \ Na_2CO_3$

The original measurement of moles has 3 significant figures, so our answer must have the same. For the number we found that is the thousandth place. The 6 in the ten-thousandth place to the right tells us to round the 0 up to a 1.

$0.541 \ mol \ Na_2CO_3$

There are approximately 0.541 moles of sodium carbonate in 57.3 grams.

6 0

2 years ago

Which elements have the quantum numbers (4,3,-2,+1/2) and (5,2,-1,-1/2)

nikklg [1K]

The elements are samarium (Sm) and silver (Ag).

Quantum numbers (4,3,-2,+½)

n = 4: Principal quantum number = 4.

l = 3: Element has 4f electrons

It is conventional to list quantum numbers in decreasing order.

Hund’s rule states that all the orbitals must be half-filled with electrons having the same spin before any can receive a second electron.

We get the following table:

Element n l mₗ mₛ

La 4 3 3 +½

Ce 4 3 2 +½

Pr 4 3 1 +½

Nd 4 3 0 +½

Pm 4 3 -1 +½

Sm 4 3 -2 +½

The element is samarium, Sm.

Quantum numbers (5,2,-1,-½)

n = 5: Principal quantum number = 5.

l = 2: Element has 5d electrons

We get the following table:

Element n l mₗ mₛ

Y 5 2 2 +½

Zr 5 2 1 +½

Nb 5 2 0 +½

Mo 5 2 -1 +½

Tc 5 2 -2 +½

Ru 5 2 2 -½

Rh 5 2 1 -½

Pd 5 2 0 -½

Ag 5 2 -1 -½

The element is silver, Ag.

Note: These assignments assume that there are no exceptions in the Periodic Table.

7 0

3 years ago

What element has a total of 3 p-sublevel electrons?

den301095 [7]

Elements with three p-electrons....

That would be N, P, As, Sb, and Bi -- elements in group 15

For example, energy diagram showing "empty" orbitals up through the 3p.

.....3p __ __ __

3s __

.....2p __ __ __

2s __

1s __

Energy diagram of phosphorous showing three unpaired electrons in 3p-sublevel

.....3p ↑_ ↑_ ↑_

3s ↑↓

.....2p ↑↓ ↑↓ ↑↓

2s ↑↓

1s ↑↓

According to Hund's rule, the electrons singly occupy the p-orbitals, and all have the same spin.

8 0

3 years ago