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nlexa [21]
2 years ago
14

On the first day of school, a class of th-grade students are given tour identical cubes of hard clay. The cubes are placed in fo

ur different conditions until the last day of school. At that time, the students make the following
Observations
Sample 1 classroom cabinet - no noticeable changes
Sample 2 near a window lighter in color
Sample 3: freezer small cracks near comers
Sample 4: bottle of water - small amount of algae on top Which sample shows evidence of physical weathering?
Samolot
Samole
0 0 0
Samples
Sample 4
Chemistry
1 answer:
matrenka [14]2 years ago
6 0

Answer:

sample 4

Explanation:

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Please help me with this question<br> Thank you!
Elza [17]

Answer:

B. 3+

Explanation:

When Fe²⁺ loses an electron, it becomes an Fe³⁺ ion.

   The loss of an electron in an atom makes the atom becomes positively charged. Further losing electrons makes the atom more positive.

 For the given ion;

 Fe²⁺   if it loses an electron more, it becomes Fe³⁺.

The expression is given as:

         Fe²⁺    →    Fe³⁺  +  e⁻

8 0
3 years ago
What factors affect the difference in the color of the stars
MAVERICK [17]

Answer:

My answer is Temperature

3 0
2 years ago
Calculate the amount of heat needed to evaporate 235.0 grams of water from 25.0°C to 100.0°C.
steposvetlana [31]
I hope this helps answer your question. :)

These problems are very hard to do digitally so I would recommend trying to practice these types of problems on paper :)

6 0
3 years ago
Compared to a 1.0-liter aqueous solution with a pH of 7.0, a 1.0-liter aqueous solution with a pH of 5.0 contains
grin007 [14]

Answer:

2. 100 times more hydroxide ions,

Explanation:

Acidity and alkalinity are measured with a logarithmic scale called pH. Each one-unit change in the pH scale corresponds to a ten-fold change in hydrogen ion concentration. Therefore, a 1.0 liter aqueous solution with a pH of 5.0 contains 100 times more hydronium ions than a 1.0 liter aqueous solution with a pH of 7.0

5 0
3 years ago
Read 2 more answers
Which statments regarding the henderson-hasselbalch equation are true?
ziro4ka [17]

Complete question is;

Which statements regarding the Henderson-Hasselbalch equation are true?

1. If the pH of the solution is known as is the pKa for the acid, the ratio of conjugate base to acid can be determined.

2. At pH = pKa for an acid, [conjugate base] = [acid] in solution.

3. At pH > pKa for an acid, the acid will be mostly ionized.

4. At pH < pKa for an acid, the acid will be mostly ionized.

A. All of the listed statements are true. B. 1, 2, and 3 are true.

C. 2, 3, and 4 are true.

D. 1, 2, and 4 are true.

Answer:

B. 1, 2, and 3 are true.

Explanation:

The formula for the Henderson-Hasselbalch equation is:

pH = pka + log₁₀([A^(-)]/[HA])

Where;

PH is acidity of solution

ka is acid dissociation constant

A^(-) is concentration of conjugate base

HA is concentration of Acid

- For statement 1; If the pH of the solution is known as is the pKa for the acid, the ratio of conjugate base to acid can be determined;

pH = pka + log₁₀([A^(-)]/[HA])

pH - pka = log₁₀([A^(-)]/[HA])

10^(pH - pka) = ([A^(-)]/[HA])

Since we can find the ratio as seen, then the statement is true

- For statement 2: At pH = pKa for an acid, [conjugate base] = [acid] in solution;

We will substitute pH for pKa;

pH = pH + log₁₀([A^(-)]/[HA])

This give;

0 = log₁₀([A^(-)]/[HA])

10^(0) = [A^(-)]/[HA]

1 = [A^(-)]/[HA]

Thus; [A^(-)] = [HA]

Thus, the statement is true

- For statement 3: At pH > pKa for an acid, the acid will be mostly ionized;

This means that;

pH - pKa is greater than 0 and thus;

10^(pH - pKa) is greater than 1.

Thus;

[A^(-)]/[HA] > 1

[A^(-)] > [HA]

So more acid is ionized than base.

So the statement is true.

- For statement 4: At pH < pKa for an acid, the acid will be mostly ionized;

This means that;

pH - pKa is less than 0 and thus;

10^(pH - pKa) is less than 1.

Thus;

[A^(-)]/[HA] < 1

[A^(-)] < [HA]

So we have more base ionized than acid. So statement is false

7 0
2 years ago
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