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4 years ago

To neutralize 1.65g LiOH, how much .150 M HCl would be needed?

1 answer:

5 0

The reaction between LiOH and HCl is;
LiOH + HCl → LiCl + H₂O

The stoichiometric ratio between LiOH and HCl is 1 : 1
moles of LiOH added = moles of HCl needed to neutralize.

Molar mass of LiOH = 24 g/mol

moles = mass / molar mass
LIOH moles = 1.65 / 24 = 0.06875 mol
Hence needed HCl moles = 0.06875 mol

Molarity = moles (mol) / Volume (L)
Hence needed HCl volume = moles / molarity
= 0.06875 mol / 0.150 mol/L
= 0.458 L = 458 mL

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Answer the following questions about the solubility of AgCl(s). The value of Ksp for AgCl(s) is 1.8 × 10−10.

Firlakuza [10]

Answer:

[Ag⁺] = 1.3 × 10⁻⁵M

s = 3.3 × 10⁻¹⁰ M

Because the common ion effect.

Explanation:

1. Value of [Ag⁺] in a saturated solution of AgCl in distilled water.

The value of [Ag⁺] in a saturated solution of AgCl in distilled water is calculated by the dissolution reaction:

AgCl(s) ⇄ Ag⁺ (aq) + Cl⁻ (aq)

The ICE (initial, change, equilibrium) table is:

AgCl(s) ⇄ Ag⁺ (aq) + Cl⁻ (aq)

I X 0 0

C -s +s +s

E X - s s s

Since s is very small, X - s is practically equal to X and is a constant, due to which the concentration of the solids do not appear in the Ksp equation.

Thus, the Ksp equation is:

Ksp = [Ag⁺] [Cl⁻]

Ksp = s × s

Ksp = s²

By substitution:

1.8 × 10⁻¹⁰ = s²

s = 1.34 × 10⁻⁵M

Rounding to two significant figures:

[Ag⁺] = 1.3 × 10⁻⁵M ← answer

2. Molar solubility of AgCl(s) in seawater

Since, the conentration of Cl⁻ in seawater is 0.54 M you must introduce this as the initial concentration in the ECE table.

The new ICE table will be:

AgCl(s) ⇄ Ag⁺ (aq) + Cl⁻ (aq)

I X 0 0.54

C -s +s +s

E X - s s s + 0.54

The new equation for the Ksp equation will be:

Ksp = [Ag⁺] [Cl⁻]

Ksp = s × ( s + 0.54)

Ksp = s² + 0.54s

By substitution:

1.8 × 10⁻¹⁰ = s² + 0.54s

s² + 0.54s - 1.8 × 10⁻¹⁰ = 0

Now you must solve a quadratic equation.

Use the quadratic formula:

$s=\dfrac{-0.54\pm\sqrt{0.54^2-4(1)(-1.8\times 10^{-10})}}{2(1)}$

The positive and valid solution is s = 3.3×10⁻¹⁰ M ← answer

3. Why is AgCl(s) less soluble in seawater than in distilled water.

AgCl(s) is less soluble in seawater than in distilled water because there are some Cl⁻ ions is seawater which shift the equilibrium to the left.

This is known as the common ion effect.

By LeChatelier's principle, you know that an increase in the concentrations of one of the substances that participate in the equilibrium displaces the reaction to the direction that minimizes this efect.

In the case of solubility reactions, this is known as the common ion effect: when the solution contains one of the ions that is formed by the solid reactant, the reaction will proceed in less proportion, i.e. less reactant can be dissolved.

3 0

3 years ago

Question 1 (True/False Worth 2 points)

pochemuha

1) Answer is: False.

Balanced chemical reaction: Pb + AlCl₃ → no reaction.

The reactivity series is a series of metals from highest to lowest reactivity. Metal higher in the reactivity series will displace another.

Aluminium (Al) is higher in activity series than lead (Pb).

That means aluminium (Al) is stronger reducing agent than lead and gives electrons easier.

This series are used to summarize information about the reactions of metals with acids or water, double displacement reactions (more reactive metals displace metals with lower reactivity) and the extraction of metals from their ores.

2) Answer is: Na3PO4 + 3KOH → 3NaOH + K3PO4, because K retains the same charge throughout the reaction.

This chemical reaction is double displacement reaction - cations (K⁺ and Na⁺) and anions (PO₄³⁻⁻ and OH⁻) of the two reactants switch places and form two new compounds.

Na₃PO₄ is sodium phosphate.

KOH is potassium hydroxide.

NaOH is sodium hydroxide.

K₃PO₄ is potassium phosphate.

3) Answer is: Zn + H2SO4 → ZnSO4 + H2.

Single replacement is reaction where neutral element metal or nonmetal become an ion as it replaces another ion in a compound.

In this balanced chemical reaction zinc (Zn) replaces hydrogen (H).

Zinc changes oxidation number from 0 to +2 (this is oxidation) and hydrogen change oxidation number from +1 to 0 (reduction).

4) Answer is: A single replacement reaction takes place because sodium is more reactive than hydrogen.

Balanced chemical reaction:

2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g).

Single replacement is reaction where neutral element metal or nonmetal become an ion as it replaces another ion in a compound.

In this balanced chemical reaction sodium (Na) replaces hydrogen (H).

Sodium changes oxidation number from 0 to +1 (oxidation) and hydrogen change oxidation number from +1 to 0 (reduction).

5) Answer is: True.

For example, balanced chemical reaction:

Ca + 2HCl → H₂ + CaCl₂.

Reduction hald reaction: 2H⁺ + 2e⁻→ H₂.

Oxidation half reaction: Ca⁰ → Ca²⁺ + 2e⁻.

In this balanced chemical reaction calcium (Ca) replaces hydrogen (H).

In this chemical reaction, calcium lost two electrons (oxidation, change oxidation number from 0 to +2) and hydrogen gain that two electrons (reduction, change oxidation number from +1 to 0).

6) Answer is: It is a single replacement reaction, and the cations in the two ionic compounds are different.

For example, balanced chemical reaction:

Ba + MgSO₄ → BaSO₄(s) + Mg.

In this balanced chemical reaction barium (Ba) replaces magnesium (Mg), because barium is higher at activity series.

Sulfate anion (SO₄²⁻) is the same in two ionic compounds, but cations (Mg²⁺ and Ba²⁺) changes.

Single Displacement is reaction where neutral element metal or nonmetal become an ion as it replaces another ion in a compound.

6 0

4 years ago

O, li, c which electrons experience the greatest effective nuclear charge? express your answer as a chemical formula.

Nataly_w [17]

The effective nuclear charge of an atom = total electrons - inner electrons For O, ENC = 8 - 2 = 6 For Li, ENC = 3 - 2 = 1 For C, ENC = 6 - 2 = 4 The electrons in O experience the greatest effective nuclear charge and that is why O is smaller than C (which is smaller than Li).

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4 years ago

The elemental mass percent composition of ascorbic acid (vitamin C ) is 40.92% C , 4.58% H , and 54.50% O . Determine the empiri

Lady bird [3.3K]

The empirical formula of ascorbic acid is C6H8O6.

<h3>Empirical formula</h3>

To calculate the empirical mass of a compound from the mass percentage of each element, the value of the molar mass of each element is used, which in this case corresponds to:

$MM_C= 12g/mol\\MM_H=1g/mol\\MM_O=16g/mol$

From this, we consider that the compound has 100 grams, so the number of moles of each element will be equal to:

$C = \frac{40.92}{12} = 3.41 \\H = \frac{4.58}{1}=4.58\\ O =\frac{54.50}{16}=3.41$

Now, divide all the values found by the smallest value, to find the amount present in each element:

$C = \frac{3.41}{3.41} = 1\\ H = \frac{4.58}{3.41} = 1.34\\O = \frac{3.41}{3.41} = 1$

As you can see, the value of moles of hydrogen resulted in a decimal number, so it is necessary to multiply all values by a number in common until the three meet as integers:

$C = 1 \times 6 = 6\\H = 1.34 \times 6 = 8\\O = 6 \times 6 = 6$

So, the empirical formula of ascorbic acid is C6H8O6.

Learn more about empirical and molecular formula in: brainly.com/question/11588623

7 0

3 years ago

How are Kelvin scale and celcius scale similar

Alekssandra [29.7K]

Answer: The Kelvin scale is related to the Celsius scale. The difference between the freezing and boiling points of water is 100 degrees in each, so that the kelvin has the same magnitude as the degree Celsius.

Explanation:

Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). The degree Celsius (symbol: °C) can refer to a specific temperature on the Celsius scale as well as serve as a unit increment to indicate a temperature interval(a difference between two temperatures or an uncertainty). “Celsius” is named after the Swedish astronomer Anders Celsius (1701-1744), who developed a similar temperature scale two years before his death.

K = °C + 273.15

°C = K − 273.15

Until 1954, 0 °C on the Celsius scale was defined as the melting point of ice and 100 °C was defined as the boiling point of water under a pressure of one standard atmosphere; this close equivalence is taught in schools today. However, the unit “degree Celsius” and the Celsius scale are currently, by international agreement, defined by two different points: absolute zero, and the triple point of specially prepared water. This definition also precisely relates the Celsius scale to the Kelvin scale, which is the SI base unit of temperature (symbol: K). Absolute zero—the temperature at which nothing could be colder and no heat energy remains in a substance—is defined as being precisely 0 K and −273.15 °C. The triple point of water is defined as being precisely 273.16 K and 0.01 °C.

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3 years ago