For the following word equations, write it as a chemical equation, then balance it.

9.86 x 10²⁸ O-atoms require what volume (L) N₂O₂ at STP?

jolli1 [7]

First, we use avogadro's number to convert atoms into moles. Then, relate the number of moles from elemental to the compound. Lastly, we use conditions at STP to calculate the volume. We do as follows:

<span>9.86 x 10²⁸ O-atoms ( 1 mol / 6.022x10^23 atoms O) ( 1 mol N2O2 / 2 mol O ) ( 22.4 L / 1 mol ) = 1833809.37 L needed</span>

8 0

2 years ago

Calculate the pressure of the CO₂ (g) in the container at 425 K.

Elanso [62]

The pressure of the CO₂ = 0.995 atm

<h3>Further explanation</h3>

The complete question

<em>A student is doing experiments with CO2(g). Originally, a sample of gas is in a rigid container at 299K and 0.70 atm. The student increases the temperature of the CO2(g) in the container to 425K.</em>

<em>Calculate the pressure of the CO₂ (g) in the container at 425 K.</em>

<em />

Gay Lussac's Law

When the volume is not changed, the gas pressure is proportional to its absolute temperature

$\tt \dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}$

P₁=0.7 atm

T₁=299 K

T₂=425 K

$\tt P_2=\dfrac{P_1\times T_2}{T_1}\\\\P_2=\dfrac{0.7\times 425}{299}=0.995 `atm$

<em />

6 0

3 years ago

The standard cell potential (E°cell) for the reaction below is +0.63 V. The cell potential for this reaction is ________ V when

tia_tia [17]

Answer : The cell potential for this reaction is 0.50 V

Explanation :

The given cell reactions is:

$Pb^{2+}(aq)+Zn(s)\rightarrow Zn^{2+}(aq)+Pb(s)$

The half-cell reactions are:

Oxidation half reaction (anode): $Zn\rightarrow Zn^{2+}+2e^-$

Reduction half reaction (cathode): $Pb^{2+}+2e^-\rightarrow Pb$

First we have to calculate the cell potential for this reaction.

Using Nernest equation :

$E_{cell}=E^o_{cell}-\frac{2.303RT}{nF}\log \frac{[Zn^{2+}]}{[Pb^{2+}]}$

where,

F = Faraday constant = 96500 C

R = gas constant = 8.314 J/mol.K

T = room temperature = $25^oC=273+25=298K$

n = number of electrons in oxidation-reduction reaction = 2

$E^o_{cell}$ = standard electrode potential of the cell = +0.63 V

$E_{cell}$ = cell potential for the reaction = ?

$[Zn^{2+}]$ = 3.5 M

$[Pb^{2+}]$ = $2.0\times 10^{-4}M$

Now put all the given values in the above equation, we get:

$E_{cell}=(+0.63)-\frac{2.303\times (8.314)\times (298)}{2\times 96500}\log \frac{3.5}{2.0\times 10^{-4}}$

$E_{cell}=0.50V$

Therefore, the cell potential for this reaction is 0.50 V

5 0

3 years ago

A gas occupies a volume of 650.0 mL when the pressure is 3.50 atm. What will the new volume be if the pressure is reduced to 1.6

Gemiola [76]

The new volume will be 1379 mL.

Explanation:

As per Boyle's law, the product of initial volume and initial pressure of any gas molecule is equal to the product of final volume and final pressure of those molecules.

So here the initial volume is 650 ml and the initial pressure is 3.50 atm. As the temperature is said to be constant, then this system will be obeying Boyle's law. So, the final pressure is given as 1.65 atm. As there is a reduction in the pressure, the volume of the gas is tend to get expanded.

$P_{1} V_{1} = P_{2} V_{2}$

So, $(650*10^{-3}*3.50)=(1.65*V_{2})$

$V_{2} = \frac{650*10^{-3}*3.50}{1.65} = 1379 mL$

So, the new volume of the gas on reduction in pressure is 1379 mL.

7 0

3 years ago

A sample of octane undergoes combustion according to the equation 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O ΔH°rxn = -11018 kJ. What mas

Anna71 [15]

Answer:

$\large \boxed{\text{528.7 g} }$

Explanation:

It often helps to write the heat as if it were a reactant or a product in the thermochemical equation.

Then you can consider it to be 11018 "moles" of "kJ"

We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.

M_r: 32.00

2C₈H₁₈ + 25O₂ ⟶ 16CO₂ + 8H₂O + 11 018 kJ

n/mol: 7280

1. Moles of O₂

The molar ratio is 25 mol O₂:11 018 kJ

$\text{Moles of O}_{2} = \text{7280 kJ} \times \dfrac{\text{25 mol O}_{2}}{\text{11 018 kJ}} = \text{16.52 mol O}_{2}$

2. Mass of O₂

$\text{Mass of C$_{8}$H}_{18} = \text{16.52 mol O}_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \textbf{528.6 g O}_{2}\\\text{The reaction requires $\large \boxed{\textbf{528.67 g O}_{2}}$}$

3 0

2 years ago