Chromium has four naturally occuring isotopes. cr-50 (mass of 49.946 amu and 4.35% abundance); cr-52 (mass of 51.941 amu and 83.79% abundance); cr-53 (mass of 52.941 amu and 9.50% abundance); and cr-54 (mass of 53.939 amu and 2.36% adundance). calculate the average atomic mass of chromium.
51.996 amu
eliminate
b) 52.000 amu
c) 52.191 amu
d) 52.25 amu

B) 52.000 amu.

Explanation:

∴ Average atomic mass of Cr = (Cr-50 mass)(its abundance) + (Cr-52 mass)(its abundance) + (Cr-53 mass)(its abundance) + (Cr-54 mass)(its abundance)

Abundance of isotope = % of the isotope / 100.

∴ Average atomic mass of Cr = (49.946 amu)(0.0435) + (51.941 amu)(0.8379) + (52.941 amu)(0.095) + (53.939 amu)(0.0236) = 52.000 amu.

So, the right choice is: B) 52.000 amu.

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.

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.