When solid mercury(I) carbonate, Hg2 CO3, is added to nitric acid, HNO3, a reaction occurs to gi

When solid mercury(I) carbonate, Hg2 CO3, is added to nitric...

When solid mercury(I) carbonate, $\mathrm{Hg}_{2} \mathrm{CO}_{3},$ is added to nitric acid, $\mathrm{HNO}_{3},$ a reaction occurs to give mercury(II) nitrate, $\mathrm{Hg}\left(\mathrm{NO}_{3}\right)_{2},$ water, and two gases $\mathrm{A}$ and $\mathrm{B}$ : $$ \mathrm{Hg}_{2} \mathrm{CO}_{3}(s)+\mathrm{HNO}_{3}(a q) \longrightarrow \\ \mathrm{Hg}\left(\mathrm{NO}_{3}\right)_{2}(a q)+\mathrm{H}_{2} \mathrm{O}(l)+\mathrm{A}(g)+\mathrm{B}(g) $$ (a) When the gases are placed in a 500.0 $\mathrm{mL}$ bulb at $20^{\circ} \mathrm{C},$ the pressure is 258 $\mathrm{mm}$ Hg. How many moles of gas are present? (b) When the gas mixture is passed over $\mathrm{CaO}(s),$ gas $\mathrm{A}$ reacts, forming $\mathrm{CaCO}_{3}(s)$ : $$ \mathrm{CaO}(s)+\mathrm{A}(g)+\mathrm{B}(g) \longrightarrow \mathrm{CaCO}_{3}(s)+\mathrm{B}(g) $$ The remaining gas $\mathbf{B}$ is collected in a 250.0 $\mathrm{mL}$ container at $20^{\circ} \mathrm{C}$ and found to have a pressure of 344 $\mathrm{mm} \mathrm{Hg}$ . How many moles of $\mathrm{B}$ are present? (c) The mass of gas $\mathbf{B}$ collected in part (b) was found to be 0.218 g. What is the density of $\mathbf{B}$ in $\mathrm{g} / \mathrm{L}$ ? (d) What is the molecular mass of $\mathbf{B},$ and what is its formula? (e) Write a balanced equation for the reaction of mercury(I) carbonate with nitric acid.

When solid mercury(I) carbonate, $\mathrm{Hg}_{2} \mathrm{CO}_{3},$ is added to nitric acid, $\mathrm{HNO}_{3},$ a reaction occurs to give mercury(II) nitrate, $\mathrm{Hg}\left(\mathrm{NO}_{3}\right)_{2},$ water, and two gases $\mathrm{A}$ and $\mathrm{B}$ :
$$
\mathrm{Hg}_{2} \mathrm{CO}_{3}(s)+\mathrm{HNO}_{3}(a q) \longrightarrow
\\
\mathrm{Hg}\left(\mathrm{NO}_{3}\right)_{2}(a q)+\mathrm{H}_{2} \mathrm{O}(l)+\mathrm{A}(g)+\mathrm{B}(g)
$$
(a) When the gases are placed in a 500.0 $\mathrm{mL}$ bulb at $20^{\circ} \mathrm{C},$ the pressure is 258 $\mathrm{mm}$ Hg. How many moles of gas are present?
(b) When the gas mixture is passed over $\mathrm{CaO}(s),$ gas $\mathrm{A}$ reacts, forming $\mathrm{CaCO}_{3}(s)$ :
$$
\mathrm{CaO}(s)+\mathrm{A}(g)+\mathrm{B}(g) \longrightarrow \mathrm{CaCO}_{3}(s)+\mathrm{B}(g)
$$
The remaining gas $\mathbf{B}$ is collected in a 250.0 $\mathrm{mL}$ container at $20^{\circ} \mathrm{C}$ and found to have a pressure of 344 $\mathrm{mm} \mathrm{Hg}$ . How many moles of $\mathrm{B}$ are present?
(c) The mass of gas $\mathbf{B}$ collected in part (b) was found to be 0.218 g. What is the density of $\mathbf{B}$ in $\mathrm{g} / \mathrm{L}$ ?
(d) What is the molecular mass of $\mathbf{B},$ and what is its formula?
(e) Write a balanced equation for the reaction of mercury(I) carbonate with nitric acid.

Key Concepts

Gas Absorption Reactions

Gas absorption reactions involve a gas being selectively reacted or absorbed by a solid or liquid, resulting in its removal from a mixture. This concept is important for isolating or quantifying specific gaseous components, as it allows for the separation and subsequent analysis of gases based on their reactivity with absorbents.

Gas Density and Molar Mass

Gas density is defined as the mass per unit volume (g/L) and can be related to the molar mass of a gas through the Ideal Gas Law. This relationship allows one to determine the molar mass by combining experimental density data with measurements of pressure, temperature, and volume, thereby providing insights into the composition and formula of the gas.

Balancing Chemical Equations

Balancing chemical equations ensures that the law of conservation of mass is obeyed in a chemical reaction. A balanced equation correctly accounts for the number of atoms of each element in the reactants and products and is vital for making accurate stoichiometric calculations in chemical reactions.

Ideal Gas Law

The Ideal Gas Law (PV = nRT) is central to solving problems involving gases under known conditions of pressure, volume, and temperature. This law allows one to calculate the number of moles of a gas when its state variables are given, making it essential for linking macroscopic measurements to the microscopic amount of material present.

Reaction Stoichiometry

Reaction stoichiometry involves using the balanced chemical equation to relate the amounts (in moles) of reactants and products. It is crucial for determining how the changes in one component of a reaction affect others, and for converting between the mass, moles, and volume of substances involved in a chemical reaction.

Transcript

00:01 So for this problem, it starts off with the reaction with an unknown gas a and a non -known gas b.

00:06 And it says that the total volume of the product of the gases is 500 milliliters, total temperature, total pressure, and it's asking us to find the total moles of the gas.

00:16 So we need to use pb equals nrt, ideal gas law.

00:22 The r value has units of liters times atm over moles times kelvin.

00:30 So we need to get our knowns into the right units.

00:36 So we'll divide by 1 ,000 to get out of milliliters into liters.

00:40 So we'll get 0 .5 liters.

00:42 We'll add 273 to get 293 kelvin.

00:46 And we'll divide by 760 to get atm.

00:53 And then solving for n, we get 0 .00704 moles.

01:06 Then the next problem, so this is our answer.

01:10 The next problem, it gives us another reaction.

01:13 And it says specifically for gas b, the volume, the temperature, and the pressure.

01:17 So again, we'll do the same thing.