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3 years ago

Unit Test

Chemistry

1 answer:

guajiro [1.7K]3 years ago

8 0

Answer:

Heat flows from faster molecules to slower molecules when they collide.

Explanation:

logics

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What is the chemical equation for a reaction between copper (ll carbonate and heat?

tino4ka555 [31]

Copper (II) Carbonate + Heat yields copper (II) oxide and carbon dioxide
Molecular Equation: CuCo3 + heat > CuO + CO2

6 0

3 years ago

Which of the following statements about standard reduction potential and spontaneity are true?

Dafna1 [17]

Answer:

A and C are true , B and D are false

Explanation:

For A)

from the first law of thermodynamics (in differential form)

dU= δQ - δW = δQ - PdV

from the second law

dS ≥ δQ/T

then

dU ≤ T*dS - p*dV

dU - T*dS + p*dV ≤ 0

from the definition of Gibbs free energy

G=H - TS = U+ PV - TS → dG= dU + p*dV + V*dp - T*dS - S*dT

dG - V*dp + S*dT = dU - T*dS + p*dV ≤ 0

dG ≤ V*dp - S*dT

in equilibrium, pressure and temperature remains constant ( dp=0 and dT=0). Thus

dG ≤ 0

ΔG ≤ 0

therefore the gibbs free energy should decrease in an spontaneous process → A reaction with a negative Gibbs standard free energy is thermodynamically spontaneous under standard conditions

For B) Since the standard reduction potential is related with the Gibbs standard free energy through:

ΔG⁰=-n*F*E⁰

then, when ΔG⁰ is negative , E⁰ is positive and therefore a coupled redox reaction with a positive standard reduction potential is thermodynamically spontaneous.

5 0

3 years ago

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Magbigay ng dahilan sa polusyon

Illusion [34]

Tea has been dropped

3 0

3 years ago

Combustion of hydrocarbons such as propane ( C3H8 ) produces carbon dioxide, a "greenhouse gas." Greenhouse gases in the Earth's

Naddika [18.5K]

Answer:

1. C₃H₈(g) + 5O₂ (g) → 3CO₂ (g) + 4H₂O (g)

2. The volume of CO₂ produced is 238 l.

Explanation:

Hi there!

The chemical equation is the following:

C₃H₈(g) + 5O₂ (g) → 3CO₂ (g) + 4H₂O (g)

The molar mass of propane is calculated as follows:

mass of 1 mol carbon = 12 g

mass of 1 mol hydrogen = 1 g

mass of 1 mol propane 3 · (12 g) + 8 · (1 g) = 44 g

If we have 150 g of propane, we will have (150 g · 1 mol / 44 g) 3.4 mol propane.

Looking at the chemical equation, notice that 1 mol propane produces 3 mol CO₂. Then 3.4 mol of propane will produce:

(3.4 mol C₃H₈ · 3 mol CO₂ / mol C₃H₈ ) 10.2 mol CO₂

Using the Ideal Gas Law we can obtain the volume of CO₂ produced:

P · V = n · R · T

Where:

P = pressure.

V = volume

n = number of moles.

R = gas constant (0.082 atm · l / ( K · mol))

T = temperature in kelvin.

V = n · R · T / P

V = 10.2 mol · 0.082 atm · l/ (K mol) · 285 K / 1 atm

Notice that 12 °C = 273 + 12 = 285 K

V = 238 l

The volume of CO₂ produced is 238 l.

Have a nice day!

7 0

4 years ago

What is the molecular formula for Tricarbon nonachloride?

vampirchik [111]

Answer:

$C_{3}Cl_{9}$

Explanation:

Molecular Formula is representation of the chemical compound in terms of the symbols of all the elements that are present in the compound followed by subscripts, which give the count of each element in that compound.

We need to write the molecular formula of Tricarbon nonachloride. Tri means three, so Tricarbon means there are 3 atoms of Carbon. Likewise, nona stands for 9, so nonachloride means there are 9 atoms of chlorine. Therefore, we can represent nonachloride as:

Carbon (3 atoms) Chlorine (9 atoms) = $C_{3}Cl_{9}$

Thus, molecular formula of Tricarbon nonachloride is $C_{3}Cl_{9}$

8 0

3 years ago

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