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Drupady [299]
3 years ago
6

30) Which of these statements are true?

Chemistry
2 answers:
anyanavicka [17]3 years ago
5 0
D because the other answers are partially right, but not all right, therefore it is D, 1 and 4.
Katen [24]3 years ago
4 0
D) 1 and 4
Chromosomes are made up of DNA. DNA strands contain short segments called genes.
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Calculate the pka of hypochlorous acid. The ph of a 0.015 m solution of hypochlorous acid has a ph of 4.64.
o-na [289]

Answer:

  • pKa = 7.46

Explanation:

<u>1) Data:</u>

a) Hypochlorous acid = HClO

b) [HClO} = 0.015

c) pH = 4.64

d) pKa = ?

<u>2) Strategy:</u>

With the pH calculate [H₃O⁺], then use the equilibrium equation to calculate the equilibrium constant, Ka, and finally calculate pKa from the definition.

<u>3) Solution:</u>

a) pH

  • pH = - log [H₃O⁺]

  • 4.64 = - log [H₃O⁺]

  • [H_3O^+]= 10^{-4.64} = 2.29.10^{-5}

b) Equilibrium equation: HClO (aq) ⇄ ClO⁻ (aq) + H₃O⁺ (aq)

c) Equilibrium constant: Ka =  [ClO⁻] [H₃O⁺] / [HClO]

d) From the stoichiometry: [CLO⁻] = [H₃O⁺] = 2.29 × 10 ⁻⁵ M

e) By substitution: Ka = (2.29 × 10 ⁻⁵ M)² / 0.015M = 3.50 × 10⁻⁸ M

f) By definition: pKa = - log Ka = - log (3.50 × 10 ⁻⁸) = 7.46

5 0
4 years ago
A sample of the mineral hematite Iron (III) oxide has a mass of 12.4g. How many moles of the mineral are present?
8090 [49]

Thus problem is providing us with the mass of iron (III) oxide as 12.4 g so the moles are required and found to be 0.0776 mol after the calculations:

<h3>Mole-mass relationships:</h3>

In chemistry, we use mole-mass relationships in order to calculate grams from moles and vice versa. In this case, since we are given the mass of iron (III) oxide as 12.4 g one can calculate the moles by firstly quantifying its molar mass:

Fe_2O_3\rightarrow 2*55.85 g/mol+3*16.00 g/mol=159.7g/mol

Then, we prepare a conversion factor in order to cancel out the grams and thus, get moles:

12.4gFe_2O_3*\frac{1molFe_2O_3}{159.7gFe_2O_3} \\\\=0.0776molFe_2O_3

Learn more about mole-mass relationships: brainly.com/question/18311376

8 0
2 years ago
Mendeleev arranged the elements by what physical property?
Alja [10]
D.) He arranged elements by Atomic Masses
3 0
4 years ago
Read 2 more answers
How many independent variables should you have in an experiment?
stepladder [879]

Answer:

One independent variable

Explanation:

The other variables are called controlled variables because the experiment is designed to keep them at an unchanging value, known as "controlling" a variable. A valid experiment should have only one independent variable.

8 0
3 years ago
What is true of a molecule? A. All molecules of a compound have the same properties. B. Each molecule of a compound has differen
lions [1.4K]

Answer: A. or C. (most likely C.)

Explanation:

All molecules of a compound have the same properties. ... All molecules of a compound have one type of atom.

Jeez, they r both true.....go with A. or C.

Hope this helps!

3 0
4 years ago
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