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NNADVOKAT [17]
3 years ago
6

What does expunge mean?

Chemistry
1 answer:
trasher [3.6K]3 years ago
3 0

It means is where something is removed or erased completely or something unwanted or unpleasant.


Hope this helps and the right meaning of expunge.

You might be interested in
My swimming pool is rectangular (16 feet by 34 feet) and has a depth of 6 feet. Lets imagine that my pool water is full to the t
Reil [10]

Answer:

Number of moles of photons required = 5.04 × 10⁴ moles

Explanation:

The energy of a photon can be calculated from Planck's equation E = hc/λ

Where h = 6.63 × 10-³⁴ Js and c, the velocity of light = 3.0 × 10⁸ m/s

Energy of one mole of photons = N₀ × hc/λ

wavelength of photon, λ = 520 nm = 5.20 × 10-⁷ m

Energy of one mole of photons = 6.02 × 10²³ × 6.63 × 10−³⁴ × 3 × 10⁸/5.20 × 10-⁷

Energy of one mole of photons = 2.30 × 10⁵ J/mol

Energy required to raise the temperature of a given mass of a substance, E = mcΔT

Where m is mass of substance,  c is specific heat capacity,  ΔT is temperature difference

Mass ofnwternin the pool = volume × density

Volume of water = Volume of swimming pool

Volume of water = 16 × 34 × 6 ft³ = 3264 ft³

1 ft³ = 28316.8 cm³; 3264 ft³ = 28316.8 × 3264 = 92426035.2 cm³

Density of water = 1 g/cm³

Mass of water = 92426035.2 cm³ × 1 g/cm³ = 92426035.2g

ΔT = 80°C - 50°C = 30°C, c = 4.18 J/g/K

Energy required to raise 92426035.2 g water by 30° C = 92426035.2 × 4.18 × 30

Energy required = 1.16 × 10¹⁰ J

Hence, number of moles of photons required = 1.16 × 10¹⁰ J/2.30 × 10⁵ J/mol

Number of moles of photons required = 5.04 × 10⁴ moles

5 0
3 years ago
Calculate the number of moles of H2 produced in the reaction of Mg(s) with HCl(aq). Mg(s) is the
Taya2010 [7]

Explanation:

Moles of metal,

=

4.86

⋅

g

24.305

⋅

g

⋅

m

o

l

−

1

=

0.200

m

o

l

.

Moles of

H

C

l

=

100

⋅

c

m

−

3

×

2.00

⋅

m

o

l

⋅

d

m

−

3

=

0.200

m

o

l

Clearly, the acid is in deficiency ; i.e. it is the limiting reagent, because the equation above specifies that that 2 equiv of HCl are required for each equiv of metal.

So if

0.200

m

o

l

acid react, then (by the stoichiometry), 1/2 this quantity, i.e.

0.100

m

o

l

of dihydrogen will evolve.

So,

0.100

m

o

l

dihydrogen are evolved; this has a mass of

0.100

⋅

m

o

l

×

2.00

⋅

g

⋅

m

o

l

−

1

=

?

?

g

.

If 1 mol dihydrogen gas occupies

24.5

d

m

3

at room temperature and pressure, what will be the VOLUME of gas evolved?

5 0
2 years ago
A 10.0 mL sample of 0.25 M NaOH(aq) is titrated with 0.10 M HCl(aq) (adding HCl to NaOH). Determine which region on the titratio
Anna11 [10]

Answer:

1) After adding 15.0 mL of the HCl solution, the mixture is before the equivalence point on the titration curve.

2) The pH of the solution after adding HCl is 12.6

Explanation:

10.0 mL of 0.25 M NaOH(aq) react with 15.0 mL of 0.10 M HCl(aq). Let's calculate the moles of each reactant.

nNaOH=\frac{0.25mol}{L} .10.0 \times 10^{-3} L=2.5 \times 10^{-3}mol

nHCl=\frac{0.10mol}{L} \times 15.0 \times 10^{-3} L=1.5 \times 10^{-3}mol

There is an excess of NaOH so the mixture is before the equivalence point. When HCl completely reacts, we can calculate the moles in excess of NaOH.

                    NaOH       +       HCl       ⇒       NaCl      +         H₂O

Initial          2.5 × 10⁻³         1.5 × 10⁻³               0                      0

Reaction    -1.5 × 10⁻³        -1.5 × 10⁻³          1.5 × 10⁻³          1.5 × 10⁻³

Final            1.0 × 10⁻³               0                 1.5 × 10⁻³          1.5 × 10⁻³

The concentration of NaOH is:

[NaOH]=\frac{1.0 \times 10^{-3} mol }{25.0 \times 10^{-3} L} =0.040M

NaOH is a strong base so [OH⁻] = [NaOH].

Finally, we can calculate pOH and pH.

pOH = -log [OH⁻] = -log 0.040 = 1.4

pH = 14 - pOH = 14 - 1.4 = 12.6

5 0
3 years ago
. All waves have a similar
Setler [38]

Answer:

They all have the same fundamental properties of reflection

5 0
3 years ago
Read 2 more answers
When patterns of stars appear to move across the sky, it provides evidence that ________.
Alexus [3.1K]

Answer:

Answered B

Explanation:

The earth moves which makes the stars and everything in space seem like its moving

6 0
3 years ago
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