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3 years ago

Hydrogen Cyanide, HCN, is a poisonous gas. The

Chemistry

1 answer:

Nikolay [14]3 years ago

5 0

mass of NaCN = 0.539 g

Further explanation

A reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.

Reaction

2NaCN (s) + H₂SO₄ (aq) ⇒ Na₂S0₄ (aq) + 2HCN (g)

MW HCN = 27,0253 g/mol

MW NaCN = 49,0072 g/mol

Assume there is 1 kg air, and mass of HCN = 300 mg

mol HCN :

mass 300 mg = 0.3 g

$\tt mol=\dfrac{0.3}{27.0253}=0.011$

NaCN : HCN = 2 : 2(mole ratio from equation), so :

mol NaCN = mol HCN = 0.011

mass NaCN :

$\tt mass=mol\times MW\\\\mass=0.011\times 49.0072=0.539~g$

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The number of valence electrons an atom has

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How could an alpha particle pass straight through the metal foil and strike the center of the phosphor screen on the other side

EleoNora [17]

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4 years ago

The active ingredient in aspirin is acetylsalicylic acid. A 2.51-g sample of acetylsalicylic acid required 27.36 mL of 0.5106 M

polet [3.4K]

Hey there!

mass of sample = 2.51 g of Aspirin

Number of moles of base ( NaOH ) :

M*V = 27.36*0.5106 = 13.9700 mmol of base

M*V = 13.68*0.516 = 7.05888 mmol of acid

pKa calculation:

pH = pKa + log(A-/HA)

3.48 = pKa + log(7.05888 / (13.9700 -7.05888))

Pka =3.49 - log(7.05888 / (13.9700 -7.05888))

pKa = 3.48

Molar mass calculation:

molar mass = mass/mol

(2.51)/(13.9700 *10⁻³) =

molar mass 180 g/mol approx

Hope that helps!

4 0

3 years ago

(8 pts) Give the answers that should be filled in the blanks below:

Olegator [25]

Answer:

[H⁺] = 1.58x10⁻⁶M; [OH⁻] = 6.31x10⁻⁹M.

pH = 8.23; pOH = 5.77

Explanation:

pH is defined as -log [H⁺] and also you have 14 = pH + pOH

Thus, for a solution of pH = 5.80.

5.80 = -log [H⁺] → [H⁺] = 10^-(5.80) = 1.58x10⁻⁶M

pOH = 14-5.80 = 8.20 → [OH⁻] = 10^-(8.20) = 6.31x10⁻⁹M

Thus, for a solution of [H⁺] = 5.90x10⁻⁹M and pH = -log 5.90x10⁻⁹M = 8.23

And pOH = 14-8.23 = 5.77

6 0

3 years ago

90 POINTSSSS!!!

Katarina [22]

Answer:

$\large \boxed{\text{-2043.96 kJ/mol}}$

Explanation:

Assume the reaction is the combustion of propane.

Word equation: propane plus oxygen produces carbon dioxide and water

Chemical eqn: C₃H₈(g) + O₂(g) ⟶ CO₂(g) + H₂O(g)

Balanced eqn: C₃H₈(g) + 5O₂(g) ⟶ 3CO₂(g) + 4H₂O(g)

(a) Table of enthalpies of formation of reactants and products

$\begin{array}{cc}\textbf{Substance} & \textbf{$\Delta_{\text{f}}$H/(kJ/mol}) \\\text{C$_{3}$H$_{8}$(g)} & -103.85 \\\text{O}_{2}\text{(g)} & 0 \\\text{CO}_{2}\text{(g)} & -393.51 \\\text{H$_{2}$O(g)} & -241.82\\\end{array}$

(b)Total enthalpies of reactants and products

$\Delta_{\text{rxn}}H^{\circ} = \sum \left( \Delta_{\text{f}} H^{\circ} \text{products}\right) - \sum \left (\Delta_{\text{f}}H^{\circ} \text{reactants} \right)\\= \text{-2147.81 kJ/mol - (-103.85 kJ/mol)}\\= \text{-2147.81 kJ/mol + 103.85 kJ/mol}\\= \textbf{-2043.96 kJ/mol}\\\text{The enthalpy change is $\large \boxed{\textbf{-2043.96 kJ/mol}}$}$

ΔᵣH° is negative, so the reaction is exothermic.

5 0

3 years ago