). In a titration, a student obtained an average titre value of 3.9 cm3 of 0.3 M HCl. If the volume of Na2CO3 solution used is 10 cm3 and the indicator used is phenolphthalein, calculate; (i). the molarity of the Na2CO3 (4 marks) (ii). the mass concentration of the Na2 theCO3. (4 marks) Assume that themass concentration of Na2CO3.xH2O is 33g/dm3 and with the formula below

I) 0.0585 M

ii)6.2 g dm-3

Explanation:

The reaction equation is given as;

Na2CO3(aq) +2HCl(aq)> 2NaCl(aq) + CO2(g) +H2O(l)

Concentration of acid CA= 0.3 M

Volume of acid VA= 3.9 cm^3

Concentration of base CB= the unknown

Volume of base VB= 10 cm^3

Number of moles of acid NA= 2

Number of moles of base NB= 1

From;

CAVA/CBVB= NA/NB

CAVANB=CBVBNA

CB= CAVANB/VBNA

substituting values;

CB= 0.3 × 3.9 × 1/ 10.0 × 2

CB= 0.0585 M

ii) mass concentration= molar concentration × molar mass

Molar mass of Na2CO3= 106 gmol-1

Mass concentration= 0.0585 × 106 = 6.2 g dm-3

answer

fusion: the energy source of stars. the energy released from the collapse of the gas into a protostar causes the center of the protostar to become extremely hot. when the core is hot enough, nuclear fusion commences. fusion is the process where two hydrogen atoms combine to form a helium atom, releasing energy.

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gas

explanation:

smoke is the matter of a gas