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3 years ago

What is the mass number?

Chemistry

2 answers:

sergey [27]3 years ago

8 0

Answer:

= The mass number,in nuclear physics ,the sum of number of protons and neutrons present in the nucleus of an atom.

Ganezh [65]3 years ago

4 0

Answer:

I hope this answers you question

Explanation:

If not plz comment

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How does friction affect energy transformation

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3 years ago

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What is the correct reaction for the dissociation (ionization) for a weak acid?

slava [35]

Answer: HA + H2O ⇌ H3O+ + H- (option #4)

Explanation: Since the acid is weak you have to use a ⇌ (equilibrium) sign. Equilibrium is denoted in a chemical equation by the ⇌ symbol. Also, when any acid dissolves into water, it produces hydronium (H3O+ or H+). Therefore, the fourth chemical reaction is your answer.

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3 years ago

Nitrogen (N) needs three more electrons to fill its outermost energy level. What is the number of electrons that Nitrogen (N) ha

Georgia [21]

Answer: 5

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5 is the number of electrons in the outermost shell

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3 years ago

Which of these substances, when dissolved in water, is a strong electrolyte? which of these substances, when dissolved in water,

Norma-Jean [14]

Option C. It is sodium nitrate because it is a strong electrolyte that comes from a strong acid (HNO3) and a strong base (KOH). It becomes a strong electrolyte when it dissolves in water, its formula is NaNO3, which is a compound that forms nitrate together with potassium nitrate and is obtained by chemical synthesis.

5 0

4 years ago

Given the following thermodynamic data, calculate the lattice energy of LiCl:

tiny-mole [99]

Answer:

$\boxed{\text{-862 kJ/mol}}$

Explanation:

One way to calculate the lattice energy is to use Hess's Law.

The lattice energy U is the energy released when the gaseous ions combine to form a solid ionic crystal:

Li⁺(g) + Cl⁻(g) ⟶ LiCl(s); U = ?

We must generate this reaction rom the equations given.

(1) Li(s) + ½Cl₂ (g) ⟶ LiCl(s); ΔHf° = -409 kJ·mol⁻¹

(2) Li(s) ⟶ Li(g); ΔHsub = 161 kJ·mol⁻¹

(3) Cl₂(g) ⟶ 2Cl(g) BE = 243 kJ·mol⁻¹

(4) Li(g) ⟶Li⁺(g) +e⁻ IE₁ = 520 kJ·mol⁻¹

(5) Cl(g) + e⁻ ⟶ Cl⁻(g) EA₁ = -349 kJ·mol⁻¹

Now, we put these equations together to get the lattice energy.

E/kJ

(5) Li⁺(g) +e⁻ ⟶ Li(g) 520

(6) Li(g) ⟶ Li(s) -161

(7) Li(s) + ½Cl₂(g) ⟶ LiCl(s) -409

(8) Cl(g) ⟶ ½Cl₂(g) -121.5

(9) Cl⁻(g) ⟶ Cl(g) + e⁻ +349

Li⁺(g) + Cl⁻(g) ⟶ LiCl(s) -862

The lattice energy of LiCl is $\boxed{\textbf{-862 kJ/mol}}$ .

3 0

3 years ago