Hydrogen peroxide can decompose to water and oxygen by the following reaction:

2h2o2 (l) 2h2o(l) + o2(g) enthalpy= -196kj

calculate the value of q when 5.00g of h20(l) decomposes at constant pressure.

The amount of heat released for the given amount of hydrogen peroxide is 14.7 kJ.

Explanation:

To calculate the number of moles, we use the equation:

Given mass of = 5.00 g

Molar mass of = 34 g/mol

Putting values in above equation, we get:

The chemical equation for the reaction of decomposition of hydrogen peroxide follows:

By Stoichiometry of the reaction:

For every 2 moles of hydrogen peroxide, the amount of heat released is 196 kJ.

So, for every 0.15 moles of hydrogen peroxide, the amount of heat released will be =

Hence, the amount of heat released for the given amount of hydrogen peroxide is 14.7 kJ.

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.

a electronegativity decreases beacuse the size of nucleus is bigger.