Chemistry, 14.01.2020 06:31 suiani8

How much energy is required to melt a 20.0lb bag of ice a 0°c? a pound (lb.) is equivalent to 0.4536. the hfusion of ice is +6.009kj/mol.

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To compute the energy, Q, needed to melt a certain amount of ice, n, in moles, we have

$Q = n \Delta H_{f}$

where the latent heat of fusion for ice is equal to 6.009 kJ/mol.

Now, since we have a 20.0 lb ice, we must first convert its mass to grams. Thus mass = (20.0)(1000)(0.4536) = 9072 g.

To find the number of moles present, we must recall that the molar mass of water (ice) is equal to 1.00794(2) + 15.9994 ≈ 18.01 g/mol. Hence, we have

$ice_{moles} = (\frac{9072 g}{1})(\frac{1 mol}{18.01 g}) =503.72 moles$

Now, to compute for the molar heat of fusion, Q,

Q = (503.72)(6.009) = 3026.9 kJ

Therefore, the amount of heat needed to melt the 20-lb bag of ice is equal to 3026.9 kJ.

3026.9 kJ

Answer from: Quest

a non redox reaction occurs when there is not a transfer of electrons. for redox reactions, which are reduction-oxidation reactions, a change in the oxidation number occurs. elements that are reduced gain electrons, and elements that are oxidized lose electrons.

explanation:

Answer from: Quest

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.

Write 15 uses of a mercury barometer along with its characterestics

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