Liquid sodium is being considered as an engine coolant. how many grams of liquid sodium (minimum) are needed to absorb 8.60 mj of energy (in the form of heat) if the temperature of the sodium is not to increase by more than 10.0 °c? use cp= 30.8 j/(k·mol) for na(l) at 500 k.

of liquid sodium is required.

Explanation: To calculate the mass of liquid sodium, we use the formula:

where,

q = heat required,   (Conversion factor: 1MJ = 1000000J)

m = Mass of liquid sodium,

M = Molar mass of liquid sodium,

c = Specific heat capacity,

= change in temperature,      (Conversion factor: 0°C = 273K)

Putting values in above equation, we get:

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.

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.