The percentage by mass of Na2CO3 in the sample is 48%.
The equation of the reaction of Na2CO3 with HCl;
Na2CO3(aq) + 2HCl(aq) ------> 2NaCl(aq) + H2O(l) + CO2(g)
Since the HCl is in excess, the excess is back titrated with NaOH as follows;
NaOH (aq) + HCl(aq) ---->NaCl(aq) + H2O(l)
Number of moles of HCl added = 0.100 M × 50/1000 L = 0.005 moles
Number of moles of NaOH added = 5.6/1000 × 0.100 M = 0.00056 moles
Since the reaction of NaOH and NaOH is 1:1, 0.00056 moles of HCl reacted with excess HCl.
Amount of HCl that reacted with Na2CO3 = 0.005 moles - 0.00056 moles = 0.0044 moles
Now;
1 mole of Na2CO3 reacts with 2 moles of HCl
x moles of Na2CO3 reacts with 0.0044 moles of HCl
x = 1 mole × 0.0044 moles / 2 moles
x = 0.0022 moles
Mass of Na2CO3 reacted = 0.0022 moles × 106 g/mol = 0.24 g
Percentage of Na2CO3 in the sample = 0.24 g/ 0.500-g × 100/1 = 48%
Learn more about back titration: brainly.com/question/25485091
Solid lead nitrate in water gives lead oxide and nitric acid
Pb(NO3)2 + H2O ---> PbO + 2 HNO3
A substance's molar mass is calculated by multiplying its relative atomic mass by the molar mass constant (1 g/mol). ... By multiplying a given mass by the molar mass, the amount of moles of the substance can be calculated.
Answer:
He blasted alpha rays at the gold foils. The Alpha rays are charged positive. When he blasted them the protons deflected and changed the course of them and the electrons surrounding the atom let them through. In the plum pudding model they were supposed to be sprinkled on which was clearly wrong according to that experiment.
Explanation:
The names of the alkanes are 2,2- dimethylbutane, 2,4- dimethylhexane, 2,2,3,3- tetramethylbutane and 4- ethyl, 3,6- dimethyl heptane.
Alkanes are saturated hydrocarbon in the organic chemistry. These are organic compounds that consists of single bonded carbon and hydrogen atoms. The common formula for writing an alkane is given by CₙH₂ₙ₊₂.
Alkanes are further divided into three more types which are:
1. Chain alkanes
2. Cycloalkanes
3. Branched alkanes
Hydrogenation method is used for preparation of alkanes from alkene and alkyne.
The names of the given compounds are:
Part A:
2,2- dimethyl butane
Part B:
2,4- dimethyl hexane
Part C:
2,2,3,3- tetramethyl butane
Part D:
4- ethyl, 3,6- dimethyl heptane
Learn more about alkanes from the link given below.
brainly.com/question/16837399
#SPJ1
