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some thermodynamic properties of ethanol are listed in the table. thermodynamic properties property value c (solid) 0.5 j/g °c c (liquid) 1.0 j/g °c c (gas) 2.0 j/g °c melting point −114 °c boiling point 78 °c how much heat is released when 40.0 g of ethanol cools from −120 °c to −136 °c? 640 j 580 j 320 j 290 j question 5(multiple choice worth 3 points) (07.02 lc) if the same large amount of heat is added to a 250 g piece of aluminum and a 150 g piece of aluminum, what will happen? the 150 g al will reach a higher temperature. the 250 g al will reach a higher temperature. there will be no significant change in the temperature of either sample. both samples will reach the same final temperature.

Q1: 320 J.

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

Explanation:

Q1:

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:

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.

the leaf is an organ of a typical plant, and the main functions are to complete photosynthesis and allow the plant to exchange gas, just like how we have the respiratory system. leaves have the stomata, which collects maintains co2 and o2 levels. this is necessary for cell metabolism. the leaf also collects sunlight using chloroplasts. succinctly, leaves own a pivotal role in sustaining plant life.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.