All categories

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.

You might be interested in

A 68-kg man whose average body temperature is 39°C drinks 1 L of cold water at 3°C in an effort to cool down. Taking the average

Dmitry [639]

Answer:

<h3>The man's average body temp. will fall by 0.6°C to 38.4°C</h3>

Explanation:

The enthalpy (heat content) of the water, using a datum of 0°C, is

Hw = Mw kg x Cp,w (specific heat capacity kJ/kg °C) x Tw °C

= 1 kg x 4.18 kJ/kg°C x 3°C = 12.5 kJ

Hman (pre drink) = 68 kg x 3.6 kJ/kg/°C x 39°C = 9547 kJ

So Hman (post drink) = H (pre drink) + Hw = 9547 + 12.5 = 9559.5 kJ because no heat is lost immediately.

But Hman (after drink) has mass 68 + 1 = 69 kg

Also his new Cp will be approx (3.6 x 68/69) + (4.18 x 1/69) = 3.608 kJ/kg°C

So Hman = 9559.5 kJ (from above) = 69 kg x 3.608 kJ/kg°C x Tnew

Therefore the man's new overall temp. = 38.4°C which is a drop of 0.6°C

8 0

3 years ago

If a small weather balloon with a volume of 40.0 L at a pressure of 1.00 atmosphere was deployed at the edge of Typhoon Odessa,

Feliz [49]

Answer: The volume of the balloon at the center of the typhoon is 41.7L.

Note: The complete question is given below;

If a small weather balloon with a volume of 40.0 L at a pressure of 1.00 atmosphere was deployed at the edge of Typhoon Odessa, what was the volume of the balloon when it reached the center?

The severity of a tropical storm is related to the depressed atmospheric pressure at its center. In August 1985, Typhoon Odessa in the Pacific Ocean featured maximum winds of about 90 mi/hr and pressure that was 40.0 mbar lower at the center than normal atmospheric pressure. In contrast, the central pressure of Hurricane Andrew (pictured) was 90.0 mbar lower than its surroundings when it hit south Florida with winds as high as 165 mi/hr.

Explanation:

Since no temperature changes were given, it is assumed to be constant. Therefore, Boyle's law which describes the relationship between pressure and volume is used to determine the new volume at the center of Typhoon Odessa. Mathematically, Boyle's law states that; P1V1 = P2V2

Assuming 1atm = 1 bar, 1mbar = 0.001atm, 40mbar = 0.040atm

P1 = 1.0atm, V1 = 40.0L, P2 = 1atm - 0.040atm = 0.960atm, V2 = ?

Using P1V1 = P2V2

V2 = P1V1/P2

V2 = 1.0 * 40.0 / 0.96

V2 = 41.67L

Therefore, the volume of the balloon at the center of the typhoon is 41.7L.

5 0

3 years ago

18. Suggest an explanation for the observations that ethanol, C2H5OH, is completely miscible with water and that ethanethiol, C2

nydimaria [60]

Answer:

Ethanol is completely miscible due to presence of Hydrogen bonding.

Ethanethiol is partially miscible due to absence of Hydrogen Bonding.

Explanation:

The miscibility of liquids depend upon the intermolecular interactions between the two liquids. The stronger the intermolecular interactions the more miscible will be the liquids.

Among the two given examples, Ethanol is more miscible in water because it exhibits hydrogen bonding which is considered the strongest intermolecular interaction. Hydrogen bonding occurs when the hydrogen atom is bonded to more electronegative atoms like Fluorine, Oxygen and Nitrogen. In this way the hydrogen atom gets partial positive charge and the electronegative atom gets partial negative charge. Hence, these partial charges results in attracting the opposite charges on other surrounding atoms.

While, in case of Ethanethiol the hydrogen atom is not bonded to any high electronegative atom hence, there will be no hydrogen bonding and therefore, there will be less interactions between the neighbour atoms.

6 0

4 years ago

How many total atoms are found in one molecule of alpo4?

Kruka [31]

There is 1 aluminium atom and 4 polonium atoms

5 0

4 years ago

Description of the outer core of the earth

notka56 [123]

It is made of liquidy molten iron that is very hot.

5 0

3 years ago