16. Which of the following is the BEST procedure for removing a hot test tube from a hot water
bath?
of
А When the test tube appears cool enough to
handle, pick it up using the tips of the fingers.
B Use a test tube clamp around the body of the
tube.
CUse a wet towel or cloth.
D Use tongs to pick up the test tube by its rim.
17. Mark and Trey were beginning their lab
activity when the teacher, Miss Sansaveria,
noticed that they were not using any safety
equipment. The activity used a test tube rack
and test tubes, several graduated cylinders, and
assorted chemicals including small pieces of
metal and some corrosive liquids. What pieces
of safety equipment should Mark and Trey
have?
A safety glasses, latex gloves, biohazards
container, fire extinguisher
B safety glasses, asbestos gloves, lab apron
Clab apron, nitrile gloves, safety glasses, broken
glass container
Dasbestos gloves, fire extinguisher, biohazards
container, lab apron
18. Mr. Duncan's biology class is observing
bacterial growth on agar solutions over time.
For safety reasons, which of the following
should NOT be allowed in the laboratory?
A open flames
B beakers
C biohazards container
D snack foods

the answer is learned

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.

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.