Select the classification for the following reaction. 2na(s) + 2h2o(l) → 2naoh(aq) + h2(g) a. precipitation b. acid-base c. redox d. combination e. none of the above

The answer to your question: I think is letter c

Explanation:

                       2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)

a.- Precipitation: is incorrect because for this kind of reactions one of the products  must be a precipitate and in the reaction we see that NAOH is soluble in water (aq) and H2 is a gas, none of them precipitate.

b. acid - base: the reactants must be an acid and a base, and the reactants of this reaction has a base but it's in the products.

c. Redox: This reaction is a redox reaction because for this reaction the oxidation numbers of the reactants must change and this happen in this reaction (H changes from +1 to 0) and Na changes from 0 to +1.

d. Combination. In this reaction the reactants combine to form a new compound and this doesn't happen here.

e. None of the above. is false because letter C is correct.

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.

1. they vary with a higher number because boiling is way hotter than melting