Burning a candle is a combustion reaction that uses wax and oxygen to produce carbon dioxide, water, and energy. when you burn a candle down in an open room, the limiting reactant is

The wax

Explanation:

The limiting reactant is the reactant in short supply in a particular reaction. This reactant determines the extent of the reaction. Oxygen in the reaction is the one in excess. As we know that oxygen is free in the atmosphere and it is in excess supply.

After the wax finishes burning the reaction stops and no more production of carbon dioxide, water and energy but oxygen still continues to abound all around.

In order to determine the amount of carbon dioxide and water that would be produce, we simply use the amount of wax to relate with them.

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 answer is c i believe