A student is working on a limiting reactant and percent yield problem, their work is shown below. They find out that the answer they wrote is incorrect, look over the work and find/highlight and explain the mistakes made; use a different colour for your notes. 13.5g H2SO4 reacts with 250mL of 0.76 M solution of NaOH, find the limiting reactant and percent yield of sodium sulfate if 10.5g is produced.

H2SO4 + 2 NaOH → 2 H2O + Na2SO4

13.5g H2SO4
98.09 mol H2SO4
1 mol Na2SO4

142.05 g Na2SO4

1 g H2SO4
1 mol H2SO4
1 mol Na2SO4

= 18,800 g Na2SO4
This is the limiting reactant

0.76 M = x / 250 = 190 mol

190 mol NaOH
1 mol Na2SO4
142.05 g Na2SO4

1 mol NaOH
1 mol Na2SO4

= 27, 000 g Na2SO4
This is the excess reactant

10.5 / 18800 * 100 = 0.056 %

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

1 a

2 d

3 a

4 c

explanation:

a polar bond is formed when electrons are shared unevenly between atoms