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3 years ago

HELP me quickly PLEASE!!!!

Chemistry

1 answer:

Elina [12.6K]3 years ago

7 0

Answer:

Q1: 320 J.

Q2: The 150 g Al will reach a higher temperature.

Explanation:

Q1:

The amount of heat added to or released from a substance (Q) can be calculated from the relation:

Q = m.c.ΔT.

where, Q is the amount of heat added or released,

m is the mass of the substance (m = 40.0 g),

c is the specific heat of the substance (c = 0.5 J/g.°C, the value of c of the solid ethanol, ethanol be solid at the temperature change mentioned).

ΔT is the temperature difference (final T - initial T) (ΔT = − 136 °C − (− 120 °C) = − 16 °C.

∴ Q = m.c.ΔT = (40.0 g)(0.5 J/g.°C)(− 16 °C) = − 320 J.

The negative sign means that the heat is released.

∴ The amount of heat is released when 40.0 g of ethanol cools from (−120 °C to −136 °C) = 320 J.

Q2:

Explanation:

The amount of heat added to a substance (Q) can be calculated from the relation:

Q = m.c.ΔT.

where, Q is the amount of heat added,

m is the mass of the substance,

c is the specific heat of the substance,

ΔT is the temperature difference (final T - initial T).

Since, Q and c is constant, ΔT will depend only on the mass of the substance (m).

∵ ΔT is inversely proportional to the mass of the substance.

∴ The piece with the lowest mass (150.0 g) will reach a higher temperature than that of a higher mass (250.0 g).

So, the right choice is: The 150 g Al will reach a higher temperature.

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3 years ago

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Putting values in equation 1, we get:

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$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

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Putting values in above equation, we get:

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