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Marizza181 [45]
2 years ago
7

Who created the first compound microscope and telescope?

Chemistry
2 answers:
vesna_86 [32]2 years ago
8 0

Answer:

Janssen

Explanation:

-BARSIC- [3]2 years ago
6 0

Answer:

Hans Martens/Zacharias Janssen

Explanation:

Janssen was the son of a spectacle maker named Hans Janssen, in Middleburg, Holland, and while Zacharias is credited with inventing the compound microscope, most historians surmise that his father must have played a vital role, since Zacharias was still in his teens in the 1590s.

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You determine that it takes 26.0 mL of base to neutralize a sample of your unknown acid solution. The pH of the solution when ex
mojhsa [17]

Answer:

a. 1.78x10⁻³ = Ka

2.75 = pKa

b. It is irrelevant.

Explanation:

a. The neutralization of a weak acid, HA, with a base can help to find Ka of the acid.

Equilibrium is:

HA ⇄ H⁺ + A⁻

And Ka is defined as:

Ka = [H⁺] [A⁻] / [HA]

The HA reacts with the base, XOH, thus:

HA + XOH → H₂O + A⁻ + X⁺

As you require 26.0mL of the base to consume all HA, if you add 13mL, the moles of HA will be the half of the initial moles and, the other half, will be A⁻

That means:

[HA] = [A⁻]

It is possible to obtain pKa from H-H equation (Equation used to find pH of a buffer), thus:

pH = pKa + log₁₀ [A⁻] / [HA]

Replacing:

2.75 = pKa + log₁₀ [A⁻] / [HA]

As [HA] = [A⁻]

2.75 = pKa + log₁₀ 1

<h3>2.75 = pKa</h3>

Knowing pKa = -log Ka

2.75 = -log Ka

10^-2.75 = Ka

<h3>1.78x10⁻³ = Ka</h3>

b. As you can see, the initial concentration of the acid was not necessary. The only thing you must know is that in the half of the titration, [HA] = [A⁻]. Thus, the initial concentration of the acid doesn't affect the initial calculation.

7 0
3 years ago
Why do your ears “pop” in an airplane?
tino4ka555 [31]
Pressure buildup in ur ear
8 0
3 years ago
This is not a homework question
Dovator [93]
What state you live in? because I know someone who does it for free
8 0
3 years ago
State with reasons, whether sulphur dioxide is acting as an oxidizing agent or a reducing agent in each of the following reactio
evablogger [386]

Answer:

A) oxidizing agent is SO2

B) NaClO is the oxidizing agent

Explanation:

A) This is a redox reaction in which oxidation and reduction occur simultaneously.

Thus, in 2H2S(g) + SO2(g) -> 2H2O(l) + 3S(s);

H2S is reduced as follows;

H2S → S + 2H+ + 2e−

We can see that SO2 has been reduced while H2S gets oxidized since it has changed state from - 2 to 0 . Thus sulphur dioxide is the oxidizing agent.

B) SO2(g) + H2O(l) + NaClO(aq) -> NaCl(aq) + H2SO4(aq)

In this, SO2 undergoes oxidation and NaClO is the oxidizing agent

4 0
3 years ago
Which topic is Eunice's project most likely about?
otez555 [7]

Answer:

pioneer species. because they are flower like species

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