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Elis [28]
4 years ago
10

3. A scientific investigation typically begins when a scientist makes observations that lead to the formation of a (n) _________

_________________?
A.law
B.theory
C.hypothesis
D.none of the above
Chemistry
1 answer:
Artist 52 [7]4 years ago
8 0

Answer:

C. Hypothesis

Explanation:

A hypothesis is usually the start of a scientific investigation.

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What kind of chemical reaction does the chemical equation sodium + chlorine → sodium chloride represent? combustion decompositio
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The answer is D, synthesis.
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Calculate the pH for each of the following cases in the titration of 25.0 mL of 0.150 M sodium hydroxide with 0.150 M HBr(aq). (
Taya2010 [7]

Answer:

a) pH = 13.176

b) pH = 13

c) pH = 12.574

d) pH = 7.0

e) pH = 1.46

f) pH = 1.21

Explanation:

HBr + NaOH ↔ NaBr + H2O

∴ equivalent point:

⇒ mol acid = mol base

⇒ (Va)*(0.150mol/L) = (0.025L)*(0.150mol/L)

⇒ Va = 0.025 L

a) before addition acid:

  • NaOH → Na+  + OH-

⇒ <em>C </em>NaOH = 0.150 M

⇒ [ OH- ] = 0.150 M

⇒ pOH = - Log ( 0.150 )

⇒ pOH = 0.824

⇒ pH = 14 - pOH

⇒ pH = 13.176

b) after addition 5mL HBr:

⇒ <em>C </em>NaOH = (( 0.025)*(0.150) - (0.005)*(0.150)) / (0.025 + 0.005) = 0.1 M

⇒ <em>C </em>HBr = (0.005)*(0.150) / ( 0.03 ) = 0.025 M

⇒ [ OH- ] = 0.1 M

⇒ pOH = 1

⇒ pH = 13

c) after addition 15mL HBr:

⇒ <em>C </em>NaOH = ((0.025)*(0.150) - (0.015)*(0.150 ))/(0.04) = 0.0375 M

⇒ <em>C </em>HBr = ((0.015)*(0.150))/(0.04) = 0.0563 M

⇒ [ OH- ] = 0.0375 M

⇒ pOH = 1.426

⇒ pH = 12.574

d) after addition 25mL HBr:

equivalent point:

⇒ [ OH- ] = [ H3O+ ]

⇒ Kw = 1 E-14 = [ H3O+ ] * [ OH- ] = [ H3O+ ]²

⇒ [ H3O+ ] = 1 E-7

⇒ pH = 7.0

d) after addition 40mL HBr:

⇒ <em>C</em> HBr = ((0.04)*(0.150) - (0.025)*(0.150)) / (0.04 + 0.025) = 0.035 M

⇒ [ H3O+ ] = 0.035 M

⇒ pH = 1.46

d) after addition 60mL HBr:

⇒ <em>C</em> HBr = ((0.06)*(0.150) - (0.025)*(0.150)) / (0.06+0.025) = 0.062 M

⇒ [ H3O+ ] = 0.062 M

⇒ pH = 1.21

8 0
4 years ago
Read 2 more answers
Why is nitro group called an ambident group?
IrinaK [193]

Answer:

An ambident ("both teeth") group is a group that can attach to another by either of two atoms. A nitro group can bond through either N or O. In organic chemistry, this property gives rise to functional group isomers.

Explanation:

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3 years ago
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Water is an example of a (n)(ionic/molecular) compound
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I think ionic ?
i dont know so dont take my anwser yet
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Water in the form of a gas is called
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I think it’s called Gaseous state or water vapor
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3 years ago
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