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3 years ago

What type of change occurs when water changes from a solid to a liquid? *

1 answer:

5 0

Melting

Melting is a change in property of matter from solid to liquid

Matter is anything that occupies space and has mass. Thus, there are fundamentally three types of matter which is solid liquid and gas. But why do gases and liquids diffuse and not solids? It is because of the molecular structure of these components of matter. If we examine the molecular structure of gas the molecules are highly scattered and liquid has also almost the same structure as mediocrely scattered that these particles can easily slip through other substances unlike solid which is entirely intact.

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Glycolic acid, which is a monoprotic acid and a constituent in sugar cane, has a pKa of 3.9. A 25.0 mL solution of glycolic acid

Phoenix [80]

Answer:

pH = 8.0

Explanation:

First, we have to calculate the moles of NaOH.

$35.8 \times 10^{-3}L.\frac{0.020mol}{L} =7.2\times 10^{-4}mol$

Let's consider the balanced equation.

C₂H₄O₃ + NaOH ⇒ C₂H₃O₃Na + H₂O

The molar ratio C₂H₄O₃: NaOH: C₂H₃O₃Na is 1: 1: 1. So, when 7.2 × 10⁻⁴ moles of NaOH react completely with 7.2 × 10⁻⁴ moles of C₂H₄O₃ they form 7.2 × 10⁻⁴ moles of C₂H₃O₃Na.

The concentration of C₂H₃O₃Na is:

$\frac{7.2\times 10^{-4}mol}{60.8 \times 10^{-3}L} =0.012M$

C₂H₃O₃Na dissociates according to the following equation:

C₂H₃O₃Na(aq) ⇒ C₂H₃O₃⁻(aq) + Na⁺(aq)

C₂H₃O₃⁻ comes from a weak acid so it undergoes basic hydrolisis.

C₂H₃O₃⁻ + H₂O ⇄ C₂H₄O₃ + OH⁻

If we know that pKa for C₂H₄O₃ is 3.9, we can calculate pKb for C₂H₃O₃⁻ using the following expression:

pKa + pKb = 14

pKb = 14 -3.9 = 10.1

10.1 = -log Kb

Kb = 7.9 × 10⁻¹¹

We can calculate [OH⁻] using the following expression:

[OH⁻] = √(Kb.Cb) where Cb is the initial concentration of the base

[OH⁻] = √(7.9 × 10⁻¹¹ × 0.012M) = 9.7 × 10⁻⁷ M

Now, we can calculate pOH and pH.

pOH = -log [OH⁻] = -log (9.7 × 10⁻⁷) = 6.0

pH + pOH = 14

pH = 14 - pOH = 14 - 6.0 = 8.0

7 0

3 years ago

What is the total charge of an iron nucleus

Dimas [21]

I believe it’s a positive charge

3 0

3 years ago

Processes that increase the density of seawater include evaporation and _____.

Elena L [17]

Correct Answer: option C: Formation of sea ice

Reason:
 In cold regions, changes in salinity alters the water present in ocean. Further, water density also changes with temperature. In general, water density in ocean water increases with decreasing temperature. This is because, when salt is ejected into the ocean as sea ice forms, the water's salinity increases. Since, salt water is heavier, the density of the water increases.

3 0

3 years ago

Read 2 more answers

He particles are mostly free of each other influence is solid , liquid , gas

Simora [160]

the most free particles are gases, then liquids, solids

4 0

3 years ago

878 kilograms to milligrams ( 8.78 E 8)

sammy [17]

K stands for thousands
1 k = 1000
1 milli = 0.001
covert 878kg to g
878 x 1000=878000 g or (8.78^5)
convert g to mg
878000 / 0.001 =878,000,000
=8.78^8
^ or E means power of

4 0

3 years ago