Avolume of 24.72±0.06 ml of hno3 solution was required for complete reaction with 0.8359±0.0007 g of na2co3, (fm 105.988±0.001 g/mol ). find the molarity of the hno3 solution and its absolute uncertainty.

Molarity of HNO₃ = 0.6379 ± 0.0020 M

Explanation:

Hi!

The equation of the reaction is as follows:

Na₂CO₃ + 2HNO₃ → H₂CO₃ + 2NaNO₃

The number of moles of Na₂CO₃ present in the reaction is:

moles Na₂CO₃ = 0.8359 ± 0.0007 g /  105.988 ± 0.001 g/mol  

First, let´s convert the absolute uncertainties in relative ones.

0.8359 ± 0.0007 g = 0.8359 ± ( (0.0007 g/ 0.8359 g) * 100%)

=0.8359g ± 0.08%

105.988 ± 0.001 g = 105.988 ± ((0.001 g/mol / 105.988 g/mol) * 100%)

= 105.988 g/mol ± 9×10⁻⁴%

Then:

moles Na₂CO₃ = (0.8359g ± 0.08%) /  (105.988 g/mol ± 9×10⁻⁴%)

moles Na₂CO₃ = (0.8359 g  / 105.988 g/mol) ± (0.08% + 9×10⁻⁴%)

moles Na₂CO₃ = 7.887 × 10⁻³ mol ± 0.08%

From the equation, we know that 2 moles of HNO₃ react with 1 mol of Na₂CO₃. Then, the number of moles of HNO₃ present in the reaction is:

moles of HNO₃ = 2 * moles of Na₂CO₃ = 2 * 7.887 × 10⁻³ mol ± 0.08%

moles of HNO₃ = 0.01577 mol ± 0.08%

This number of moles was present in 24.72 ml ± 0.2%. Then, in 1 l there will be:

moles of HNO₃ in 1l = 0.01577 mol ± 0.08% * 1000 ml / 24.72 ml ± 0.2%

moles of HNO₃ in 1l = 0.6379 mol ± (0.08% + 0.2%)

moles of HNO₃ in 1l = 0.6379 mol ± 0.3%

Converting the relative uncertainty to absolute one:

0.3% *  0.6379 mol / 100% = 2 × 10⁻³ mol

Then, the molarity of HNO₃ will be:

Molarity of HNO₃ = 0.6379 ± 0.0020 M

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

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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.

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