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10.0g
22.1g
32.9g
5.6g
Answer:
22.1 g
Explanation:
The balanced reaction equation which serves as a guide in solving the problem is given as;
CaO(s) + 2NaCl(aq) ------> Na2O(s) + CaCl2(aq)
The question clearly specifies that sodium chloride is the reactant in excess. This means that calcium oxide should be used to calculate the theoretical yield of sodium oxide.
Number of moles of calcium oxide reacted = mass of calcium oxide / molar mass of calcium oxide
Molar mass of calcium oxide = 56.0774 g/mol
Mass of calcium oxide = 20.0g
Number of moles of calcium oxide = 20.0 g/ 56.0774 g/mol = 0.3566 moles
From the balanced reaction equation;
1 mole of calcium oxide produces 1 mole of sodium oxide
Therefore, 0.3566 moles of calcium oxide will produce 0.3566 moles of sodium oxide.
Mass of sodium oxide produced = number of moles × molar mass
Molar mass of sodium oxide= 61.9789 g/mol
Mass of sodium oxide = 0.3566 moles × 61.9789 g/mol
Mass of sodium oxide= 22.1 g
Answer:
22.1g
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
CaO + 2NaCl —> Na2O + CaCl2
Next, we shall determine the mass of CaO that reacted and the mass of Na2O produced from the balanced equation.
This is illustrated below:
Molar mass of CaO = 40 + 16 = 56g/mol
Mass of CaO from the balanced equation = 1 x 56 = 56g
Molar mass of Na2O = (23x2) + 16 = 62g/mol
Mass of Na2O from the balanced equation = 1 x 62 = 62g
From the balanced equation above,
56g of CaO reacted to produce 62g of Na2O.
Finally, we can determine the theoretical yield of Na2O as follow:
From the balanced equation above,
56g of CaO reacted to produce 62g of Na2O.
Therefore, 20g of CaO will react to produce = (20 x 62)/56 = 22.1g of Na2O.
Therefore, the theoretical yield of Na2O is 22.1g
Answer is: A compound is a pure substance because its molecule cannot be broken down into simpler particles by physical means.
Pure substance is made of only one type of atom (element) or only one type of molecule, it has definite and constant composition with distinct chemical properties. Pure substances can be separated chemically, not physically, that is difference between pure substances and mixtures.
Electrolysis of water (pure substance) is the chemical separation, because from one molecule (water) two molecules (hydrogen and oxygen) are produced. Water is separeted into two molecules:
Reaction of reduction at cathode: 2H⁺(aq) + 2e⁻ → H₂(g).
Reaction of oxidation at anode: 2H₂O(l) → O₂(g) + 4H⁺(aq) + 4e⁻.
Answer:
Answer:
group # = # valence electrons
group 2= 2 valence electrons
Explanation:
Mg is in group #2 and subsequently has 2 valence electrons (electrons on the outermost shell)
(2) 2 days (4) 4 days
Unstable heavy atoms will undergo radioactive decay to produce stable species. The half life time of the isotope which undergone a decay of 75 mg in 32 days is 18 days.
The half life time of a radioactive sample is the time taken to reduce it to half of the initial amount by decay.
The heavy unstable material have very short half life and they will easily undergoes radioactive decay by emitting certain radiation.
Radioactive decay is a firs order reaction and have the equation to find the radioactive constant as follows:
Where, t is the time of decay and Ni and Nt be the initial and final amount respectively.
It is given that 5 mg is remaining out of 80 mg after 32 days. Thus the radioactive constant is calculated as follows:
Now the half life time of the decay is calculated as below:
t(1/2) = 0.693 /decay constant
= 0.693/0.0376
= 18 days
Therefore, the half life time of the isotope which undergone a decay of 75 mg in 32 days is 18 days.
To find more about radioactive decay, refer the link below:
#SPJ5
What did Bohr’s model of the atom include that Rutherford’s model did not have?
The answer is energy levels