Which of the following is a chemical change?

The student is now told that the four solids, in no particular order, are aluminum chloride (AlCl3), sugar (C6H12O6), benzoic ac

zaharov [31]

Answer:

AlCl₃, NaBr, C₆H₅COOH, C₆H₁₂O₆.

Explanation:

The more ions in solution, the greater the conductivity of a solution because these charged particles can carry electrons in the solution.

In the first place, when AlCl₃ dissolves in water it produces 4 ions:

AlCl₃(aq) ⇄ Al³⁺(aq) + 3 Cl⁻(aq)

If the solution is 0.20M in AlCl₃, it will be 4 x 0.20M = 0.80M in ions.

Secondly, NaBr is a strong electrolyte (complete ionization) so it produces 2 moles of ions per each mole of NaBr dissolved:

NaBr(aq) ⇄ Na⁺(aq) + Br⁻(aq)

If the solution is 0.20M in NaBr, it will be 2 x 0.20M = 0.40M in ions.

Then, benzoic acid is a weak electrolyte (partial ionization) so it will produce less than 2 moles of ions per each mole of benzoic acid dissolved:

C₆H₅COOH(aq) ⇄ C₆H₅COO⁻(aq) + H⁺(aq)

If the solution is 0.20M in benzoic acid, the solution will be far below 0.40M in ions.

Finally, sugar has only nonpolar covalent bonds so it will produce no ions in solution, thus being a poor electricity conductor.

4 0

3 years ago

The number of protons plus the number of neutrons in an atom is called its 7 number. for carbon-12, this number is

emmasim [6.3K]

The mass of Carbon-12 is 12.

8 0

3 years ago

Mendeleev arranged the known chemical elements in a table according to increasing

vesna_86 [32]

Atomic mass. Which is the number of protons and neutrons combined.

8 0

3 years ago

Part A Which acid in each of the following pairs has the stronger conjugate base? Match the words in the left column to the appr

vichka [17]

Answer:

HF

H₂S

H₂CO₃

NH₄⁺

Explanation:

Which acid in each of the following pairs has the stronger conjugate base?

According to Bronsted-Lowry acid-base theory, the weaker an acid, the stronger its conjugate acid. Especially for weak acids, pKa gives information about the strength of such acid. The higher the pKa, the weaker the acid.

Of the acids HCl or HF, the one with the stronger conjugate base is HF because it is a weak acid.

Of the acids H₂S or HNO₂, the one with the stronger conjugate base is H₂S because it is a weaker acid. pKa (H₂S) = 7.04 > pKa (HNO₂) = 3.39

Of the acids H₂CO₃ or HClO₄, the one with the stronger conjugate base is H₂CO₃ because it is a weak acid.

Of the acids HF or NH₄⁺, the one with the stronger conjugate base is NH₄⁺ because it is a weaker acid. pKa (HF) = 3.17 < pKa (NH₄⁺) = 9.25

6 0

3 years ago

A recessive gene is described as one that

djyliett [7]

Answer:

<h2>C) may be hidden </h2>

Explanation:

A gene is a unit of heredity which is transferred from parents to offspring and it control the traits.

Alternative form of gene are known as alleles.

Gene may be dominant or recessive

Dominant gene expresses in both homozygous as well as in heterozygous condition, while recessive gene expresses in homozygous condition only, when it present with dominant gene, its effect is hidden by dominant gene. Dominant gene is represented by capital letter while recessive gene is represented by small letter.

5 0

3 years ago