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3 years ago

Which processes occur when energy is removed from a substance

Chemistry

1 answer:

ratelena [41]3 years ago

8 0

Answer:

Note that melting and vaporization are endothermic processes in that they absorb or require energy, while freezing and condensation are exothermic process as they release energy.

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How much CO2 is produced from the combustion of a tank of propane C3H8? Assume the tank contains 9kgs of propane and the molecul

Zinaida [17]

<u>Answer:</u> The mass of carbon dioxide produced is 26.9 kg

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of propane = 9 kg = 9000 g (Conversion factor: 1 kg = 1000 g)

Molar mass of propane = 44.1 g/mol

Putting values in equation 1, we get:

$\text{Moles of propane}=\frac{9000g}{44.1g/mol}=204.08mol$

The chemical equation for the combustion of propane follows:

$C_3H_8+5O_2\rightarrow 3CO2+4H_2O$

By Stoichiometry of the reaction:

1 mole of propane produces 3 moles of carbon dioxide.

So, 204.08 moles of propane will produce = $\frac{3}{1}\times 204.08=612.24mol$ of carbon dioxide.

Now, calculating the mass of carbon dioxide by using equation 1, we get:

Molar mass of carbon dioxide = 44.01 g/mol

Moles of carbon dioxide = 612.24 moles

Putting values in equation 1, we get:

$612.24mol=\frac{\text{Mass of carbon dioxide}}{44.01g/mol}\\\\\text{Mass of carbon dioxide}=(612.24mol\times 44.01g/mol)=26944.7g=26.9kg$

Hence, the mass of carbon dioxide produced is 26.9 kg

3 0

3 years ago

Compare how entropy changes for the following two systems

bazaltina [42]

Remember the fact

Randomness follows the order

Gas>Liquid>Solid

#System A

As solid particles are dissolved in water their randomness increases so entropy increases

#System B

Gas is converted to liquid so entropy decreases as randomness decreases

3 0

2 years ago

We can prove a theory to be correct by performing the right experiment. False or true

eimsori [14]

Answer:

true

Explanation:

because if you find the right answer that proves the theory to be correct.

4 0

3 years ago

The alveoli have certain adaptation for efficient exchange of gases. Which of these is an adaptation?

Reptile [31]

Answer:

Alveoli are the numerous small air sacs attached to the bronchiole in the lungs and in close contact with blood vessels for gas exchange essential for the human respiratory system for the diffusion of oxygen and carbon dioxide.

Adaptations of the alveoli:

- Alveoli are folded in a shape that helps in increase their surface area to volume ratio that allows diffusion easily.

- Alveolar walls and blood-carrying vessels are one cell thick helps in providing gases exchange with a short diffusion distance.

- The lining of the alveoli walls are moist that helps in dissolving gases.

- The walls of alveoli are permeable walls - allow gases to pass through.

- closer to blood supply especially capillaries to allow easy movement or diffusion of gases to and from the blood cells.

4 0

3 years ago

Propanol has a normal boiling point of 97.8°C. At 400 torr, it has a boiling point of 82.0°C. What is the heat of vaporization?2

Sedbober [7]

Answer:

44.5 kJ/mol

Explanation:

Propanol has a normal boiling point of T₁ = 97.8°C = 371.0 K. "Normal" refers to a pressure P₁ = 1 atm = 760 torr. At 400 torr (P₂), it has a boiling point of T₂ = 82.0°C = 355.2 K. We can find the heat of vaporization (ΔHvap) using the two point form of the Clausius-Clapeyron equation.

$ln(\frac{P_{2}}{P_{1}} )=\frac{-\Delta H_{vap}}{R} .(\frac{1}{T_{2}}-\frac{1}{T_{1}})\\ln(\frac{400torr}{760torr})=\frac{-\Delta H_{vap}}{8.314J/K.mol} .(\frac{1}{355.2K}-\frac{1}{371.0K})\\\Delta H_{vap}=4.45 \times 10^{4} J/mol=44.5 kJ/mol$

5 0

3 years ago