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3 years ago

Which of the following would cause entropy to decrease?

Chemistry

1 answer:

svetlana [45]3 years ago

4 0

Answer:

Explanation:

Entropy can be decreased only in the cases when liquid is converted to solid

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A sample from a local stream is found to have 3.0 ppm nitrates (in the form of sodium nitrate). How many grams of sodium nitrate

maw [93]

Answer:

0.01028 grams of sodium nitrate would there be in 2.5 L of the stream.

Explanation:

The ppm is the amount of solute (in milligrams) present in kilogram of a solvent. It is also known as parts-per million.

To calculate the ppm of oxygen in sea water, we use the equation:

$\text{ppm}=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 10^6$

Both the masses are in grams.

We are given:

The ppm concentration of nitrates = 3.0 ppm

Mass of nitrates = x

Mass of steam= m

Volume of steam = V = 2.5 L = 2500 ml ( 1 L = 1000 mL)

Density of steam = d = 1.0 g/mL

$M=d\times V=1.0 g/mL\times 2500 mL = 2500 g$

Putting values in above equation, we get:

$3.0=\frac{x}{2500 g}\times 10^6$

$x=0.0075 g$

Mass of nitrate = 0.0075 g

Moles of nitrate = $\frac{0.0075 g}{62 g/mol}=0.0001210 mol$

1 mole of nitrate ion is present in 1 mole of sodium nitrate.

Then 0.0001210 moles of nitrate will be present in :

$\frac{1}{1}\times 0.0001210 mol=0.0001210 mol$ of sodium nitrate;

Mass of 0.0001210 moles of sodium nitrate :

0.0001210 mol × 85 g/mol = 0.01028 g

0.01028 grams of sodium nitrate would there be in 2.5 L of the stream.

6 0

4 years ago

_________ is the mechanical separation of a mixture based upon the sizes of the mixtures components.

levacccp [35]

Answer:

Sieving

Explanation:

Sieving is a mechanical separation technique which depends on the relative sizes of particles in the mixture.

A mesh is used to discriminate between particle sizes. Particles in the mixture which are larger than the mesh size do not pass through the sieve, hence particles whose size is less than that of the mesh are separated from the rest of the particles in the mixture.

4 0

3 years ago

Which of the following statements about ions is NOT CORRECT?

madam [21]

Answer:

B. Anions are formed when an atom loses electrons.

7 0

3 years ago

How to find density?

Natasha2012 [34]

P=m/V should be the equation to get your answer

7 0

3 years ago

Use the periodic table to identify the element with the electron configuration 1s²2s²2p⁴. Write its orbital diagram, and give th

natta225 [31]

Answer:

1. Orbital diagram

2p⁴ ║ ↑↓ ║ "↑" ║ ↑

2s² ║ ↑↓ ║

1s² ║ ↑↓ ║

2. Quantum numbers

n = 2,
l = 1,

$m_{l}$ = 0,

$m_{s}$ = +1/2

Explanation:

The fill in rule is:

Follow shell number: from the inner most shell to the outer most shell, our case from shell 1 to 2

Follow the The Aufbau principle, 1s<2s<2p<3s<3p<4s<3d<4p<5s<4d<5p<6s<4f<5d<6p<7s<5f<6d<7p
Hunds' rule: Every orbital in a sublevel is singly occupied before any orbital is doubly occupied. All of the electrons in singly occupied orbitals have the same spin (to maximize total spin).

So, the orbital diagram of given element is as below and the sixth electron is marked between " "

2p⁴ ║ ↑↓ ║ "↑" ║ ↑

2s² ║ ↑↓ ║

1s² ║ ↑↓ ║

The quantum number of an electron consists of four number:

n (shell number, - 1, 2, 3...)
l (subshell number or orbital number, 0 - orbital s, 1 - orbital p, 2 - orbital d...)
$m_{l}$ (orbital energy, or "which box the electron is in"). For example, orbital p (l = 1) has 3 "boxes", it was number from -1, 0, 1. Orbital d (l = 2) has 5 "boxes", numbered -2, -1, 0, 1, 2
$m_{s}$ (spin of electron), either -1/2 or +1/2

In our case, the electron marked with " " has quantum number

n = 2, shell number 2,
l = 1, subshell or orbital p,

$m_{l}$ = 0, 2nd "box" in the range -1, 0, 1

$m_{s}$ = +1/2, single electron always has +1/2

3 0

4 years ago