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Scilla [17]
3 years ago
8

When a physical change in a sample occurs, which of the following does NOT change?

Chemistry
2 answers:
Vanyuwa [196]3 years ago
8 0
I think thee correct answer from the choices listed above is option D. <span>When a physical change in a sample occurs, composition of the sample does not change. It stays the same. Also, the properties of the sample will still be the same. Hope this answers the question.</span>
Lunna [17]3 years ago
5 0
D. Composition does not change during a physical change.
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What do you observe about the movement of the particles in the medium?
horrorfan [7]

Answer:

The particles of the medium just vibrate in place.

Explanation:

As they vibrate, they pass the energy of the disturbance to the particles next to them, which pass the energy to the particles next to them, and so on. Particles of the medium don't actually travel along with the wave.

5 0
3 years ago
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What was the oxygen crisis
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8 0
3 years ago
Which solution below has the highest concentration of hydroxide ions?a. pH= 3.21b. pH= 7.00c. pH= 7.93d. pH= 12.59e. pH= 9.82
Sloan [31]

Answer:

  • <em>The solution that has the highest concentration of hydroxide ions is </em><u>d. pH = 12.59.</u>

Explanation:

You can solve this question using just some chemical facts:

  1. pH is a measure of acidity or alkalinity: the higher the pH the lower the acidity and the higher the alkalinity.
  2. The higher the concentration of hydroxide ions the lower the acidity or the higher the alkalinity of the solution, this is the higher the pH.

Hence, since you are asked to state the solution with the highest concentration of hydroxide ions, you just pick the highest pH. This is the option d, pH = 12.59.

These mathematical relations are used to find the exact concentrations of hydroxide ions:

  • pH + pOH = 14 ⇒ pOH = 14 - pH

  • pOH = - log [OH⁻] ⇒ [OH^-]=10^{-pOH}

Then, you can follow these calculations:

Solution    pH        pOH                            [OH⁻]

a.               3.21       14 - 3.21 = 10.79        antilogarithm of 10.79 = 1.6 × 10⁻¹¹

b.               7.00      14 - 7.00 = 7.00        antilogarithm of 7.00 = 10⁻⁷

c.                7.93      14 - 7.93 = 6.07        antilogarithm of 6.07 = 8.5 × 10⁻⁷

d.               12.59     14 - 12.59 = 1.41        antilogarithm of 1.41 = 0.039

e.               9.82      14 - 9.82 = 4.18        antilogarithm of 4.18 = 6.6 × 10⁻⁵

From which you see that the highest concentration of hydroxide ions is for pH = 12.59.

5 0
3 years ago
Can someone please please help me out ?
GarryVolchara [31]

Answer:

4.823 x 10^-19 J

Explanation:

Energy is calculated by E = hv where h - Planck's constant in joule.s

v - frequency.

in this particular question the wave length is 4.12 x 10^-7 m. to exhaustively use this we need a relation between wave length & frequency. c=wv where C is approximately 3 x 10^8m/s

-v = c/w = 3x10^8m/s / 4.12 x 10^-7m = 7.28 x 10^14 Hz or 1/sec

now we can simply use Planck's constant in E=hv =

(6.626 x 10^-34) x (7.28 x 10^14Hz) = 4.823 x 10^-19 J.

6 0
3 years ago
Consider the work of Thomson, Rutherford, and Bohr. In your opinion, which was the most important and why? Be sure to state what
kobusy [5.1K]
The two of them both made models of the current atom, which was very excellent because now we could imagine how an atom would look.  I would say that the best one was the electron orbital configuration because we needed to know what valence electrons are. 
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4 years ago
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