Asample contains 6.73 g of na2co3 in water to make a total of 250.0 ml of solution. what is the molarity of sodium carbonate in this solution and its mass-% ? use 1.00 g/ml as the density of the solution.

Molarity of Na₂CO₃ = 0.25M

% mass = 2.69

Explanation:

Molarity means mole of solute in 1L of solution

Molar mass of solute (Na₂CO₃) = 105,98 g/m

Moles = mass / molar mass → 6.73 g / 105.98 g/m = 0.0635 m

Mol/L = [M]

0.0635 mol/0.250L = 0.25M

Density of solution = Solution mass / Solution volume

1 g/ml = Solution mass / 250 mL → Solution mass is 250g

% mass will be:

In 250 g of solution we have 6.73 g of solute

in 100 g of solution we have (100 . 6.73)/250 = 2.69

The molarity of Na2CO3 in the solution = 0.254 M

The mass % of Na2CO3 is 2.69 %

Explanation:

Step 1: Data given

Mass of Na2CO3 = 6.73 grams

Volume of the solution = 250.0 mL

Density = 1.00g/mL

Molar mass of Na2CO3 = 105.99 g/mol

Step 2: Calculate moles of Na2CO3

Moles Na2CO3 = 6.73 grams / 105.99 g/mol

Moles Na2CO3 = 0.0635 moles

Step 3: Calculate molarity of Na2CO3

Molarity = moles / volume

Molarity = 0.0635 moles / 0.250 L

Molarity = 0.254 M

Step 4: Calculate mass of the solution

Mass = volume * density

Mass = 250 mL * 1.00g/mL

Mass = 250 grams

Step 5: Calculate mass %

mass% = (6.73 g / 250 g)*100%

mass % =  2.69 %

The mass % of Na2CO3 is 2.69 %

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.

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72