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3 years ago

Which is a FALSE statement about elements?

Chemistry

2 answers:

svetlana [45]3 years ago

6 0

C. Not each element has a known neutron number

OlgaM077 [116]3 years ago

3 0

Answer:

Option c, Each element has its own neutron number

Explanation:

Atomic number of any element is unique. All the atoms of an element have the same atomic number. Atomic number defines the identity of the element.

Atomic number is equal to number of proton. So, number of proton is also unique or each element has its own number of proton.

Chemical symbols are used to represent element in easiest way. Therefore, chemical symbol has to be specific for each element.

Atoms of an element can have different number of neutrons. Atoms of an element having same no. of proton but different no. of neutron are called isotopes.

So, among the given option, option c is false.

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How do you do this problem?

xeze [42]

Answer:

Ag₂CrO₄(s) + H⁺(aq) ⟶ 2Ag⁺(aq) + HCrO₄⁻(aq)

Explanation:

Ag₂CrO₄(s) ⇌ 2Ag⁺(aq) + CrO₄²⁻(aq).

Silver chromate is the salt of a strong base (AgOH) and a weak acid (H₂CrO₄).

HCrO₄⁻ is an even weaker acid than H₂CrO₄, so CrO₄²⁻ is a strong base.

Any added H⁺ will immediately combine with the chromate ions according to the reaction

H⁺ + CrO₄²⁻ ⟶ HCrO₄⁻

thereby removing chromate ions from solution.

According to Le Châtelier's Principle, more silver chromate will dissolve to replace the chromate ions that the H⁺ removes.

The overall equation for the reaction is

Ag₂CrO₄(s) ⇌ 2Ag⁺(aq) + CrO₄²⁻(aq)

H⁺(aq) + CrO₄²⁻(aq) ⟶ HCrO₄⁻(aq)

Ag₂CrO₄(s) + H⁺(aq) ⟶ 2Ag⁺(aq) + HCrO₄⁻(aq)

3 0

4 years ago

What is the ph of a 4.8 m pyridine solution that has kb = 1.9 × 10-9? the equation for the dissociation of pyridine is?

Eddi Din [679]

Answer: 9.98

Explanation:

1) The equation for the dissociation of pyridine is:

C₅H₅N₅(aq )+ H₂O(l) ⇄ C₅H₅NH⁺(aq) + OH⁻(aq)

2) Kb equation:

Kb = [C₅H₅NH⁺(aq)] [OH⁻(aq)] / [C₅H₅N₅(aq )]

Where:

[C₅H₅NH⁺(aq)] = [OH⁻(aq)] ← from the equilibrium reaction

[C₅H₅N₅(aq )] = 4.8 M ← from the statement

⇒ 1.9 × 10 ⁻⁹ = x² / 4.8 ⇒ x² = 9.12 × 10⁻⁹

⇒ x = 9.55 × 10⁻⁵ = [OH⁻(aq)]

3) pOH

pOH = - log [OH⁻(aq)] = 4.02

4) pOH + pH = 14

⇒ pH = 14 - 4.02 = 9.98

4 0

3 years ago

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A _______ is a repeating disturbance or vibration that transfers or moves energy from place to place without transporting mass.

Harlamova29_29 [7]

The answer is D ( wave )

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3 years ago

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Question 16

viva [34]

Answer: D

I think it should be $NH_{4} NO2$

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Explanation:

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3 years ago

If all of the above images represents the same material, which has the highest temperature?

aleksklad [387]

Answer:

hiii

Explanation:

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4 years ago